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Publisher: Oxford University Press   (Total: 370 journals)

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Showing 1 - 200 of 370 Journals sorted alphabetically
Acta Biochimica et Biophysica Sinica     Hybrid Journal   (Followers: 6, SJR: 0.881, h-index: 38)
Adaptation     Hybrid Journal   (Followers: 8, SJR: 0.111, h-index: 4)
Aesthetic Surgery J.     Hybrid Journal   (Followers: 6, SJR: 1.538, h-index: 35)
African Affairs     Hybrid Journal   (Followers: 60, SJR: 1.512, h-index: 46)
Age and Ageing     Hybrid Journal   (Followers: 84, SJR: 1.611, h-index: 107)
Alcohol and Alcoholism     Hybrid Journal   (Followers: 15, SJR: 0.935, h-index: 80)
American Entomologist     Full-text available via subscription   (Followers: 6)
American Historical Review     Hybrid Journal   (Followers: 130, SJR: 0.652, h-index: 43)
American J. of Agricultural Economics     Hybrid Journal   (Followers: 41, SJR: 1.441, h-index: 77)
American J. of Epidemiology     Hybrid Journal   (Followers: 160, SJR: 3.047, h-index: 201)
American J. of Hypertension     Hybrid Journal   (Followers: 23, SJR: 1.397, h-index: 111)
American J. of Jurisprudence     Hybrid Journal   (Followers: 16)
American J. of Legal History     Full-text available via subscription   (Followers: 5, SJR: 0.151, h-index: 7)
American Law and Economics Review     Hybrid Journal   (Followers: 25, SJR: 0.824, h-index: 23)
American Literary History     Hybrid Journal   (Followers: 12, SJR: 0.185, h-index: 22)
Analysis     Hybrid Journal   (Followers: 24)
Annals of Botany     Hybrid Journal   (Followers: 35, SJR: 1.912, h-index: 124)
Annals of Occupational Hygiene     Hybrid Journal   (Followers: 26, SJR: 0.837, h-index: 57)
Annals of Oncology     Hybrid Journal   (Followers: 47, SJR: 4.362, h-index: 173)
Annals of the Entomological Society of America     Full-text available via subscription   (Followers: 8, SJR: 0.642, h-index: 53)
Annals of Work Exposures and Health     Hybrid Journal  
AoB Plants     Open Access   (Followers: 3, SJR: 0.78, h-index: 10)
Applied Economic Perspectives and Policy     Hybrid Journal   (Followers: 19, SJR: 0.884, h-index: 31)
Applied Linguistics     Hybrid Journal   (Followers: 51, SJR: 1.749, h-index: 63)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1, SJR: 0.779, h-index: 11)
Arbitration Intl.     Full-text available via subscription   (Followers: 20)
Arbitration Law Reports and Review     Hybrid Journal   (Followers: 13)
Archives of Clinical Neuropsychology     Hybrid Journal   (Followers: 26, SJR: 0.96, h-index: 71)
Aristotelian Society Supplementary Volume     Hybrid Journal   (Followers: 2, SJR: 0.102, h-index: 20)
Arthropod Management Tests     Hybrid Journal   (Followers: 2)
Astronomy & Geophysics     Hybrid Journal   (Followers: 47, SJR: 0.144, h-index: 15)
Behavioral Ecology     Hybrid Journal   (Followers: 48, SJR: 1.698, h-index: 92)
Bioinformatics     Hybrid Journal   (Followers: 247, SJR: 4.643, h-index: 271)
Biology Methods and Protocols     Hybrid Journal  
Biology of Reproduction     Full-text available via subscription   (Followers: 9, SJR: 1.646, h-index: 149)
Biometrika     Hybrid Journal   (Followers: 19, SJR: 2.801, h-index: 90)
BioScience     Hybrid Journal   (Followers: 28, SJR: 2.374, h-index: 154)
Bioscience Horizons : The National Undergraduate Research J.     Open Access   (Followers: 1, SJR: 0.213, h-index: 9)
Biostatistics     Hybrid Journal   (Followers: 16, SJR: 1.955, h-index: 55)
BJA : British J. of Anaesthesia     Hybrid Journal   (Followers: 143, SJR: 2.314, h-index: 133)
BJA Education     Hybrid Journal   (Followers: 66, SJR: 0.272, h-index: 20)
Brain     Hybrid Journal   (Followers: 60, SJR: 6.097, h-index: 264)
Briefings in Bioinformatics     Hybrid Journal   (Followers: 45, SJR: 4.086, h-index: 73)
Briefings in Functional Genomics     Hybrid Journal   (Followers: 4, SJR: 1.771, h-index: 50)
British J. for the Philosophy of Science     Hybrid Journal   (Followers: 34, SJR: 1.267, h-index: 38)
British J. of Aesthetics     Hybrid Journal   (Followers: 25, SJR: 0.217, h-index: 18)
British J. of Criminology     Hybrid Journal   (Followers: 526, SJR: 1.373, h-index: 62)
British J. of Social Work     Hybrid Journal   (Followers: 82, SJR: 0.771, h-index: 53)
British Medical Bulletin     Hybrid Journal   (Followers: 7, SJR: 1.391, h-index: 84)
British Yearbook of Intl. Law     Hybrid Journal   (Followers: 27)
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3, SJR: 1.474, h-index: 31)
Cambridge J. of Economics     Hybrid Journal   (Followers: 58, SJR: 0.957, h-index: 59)
Cambridge J. of Regions, Economy and Society     Hybrid Journal   (Followers: 11, SJR: 1.067, h-index: 22)
Cambridge Quarterly     Hybrid Journal   (Followers: 11, SJR: 0.1, h-index: 7)
Capital Markets Law J.     Hybrid Journal  
Carcinogenesis     Hybrid Journal   (Followers: 2, SJR: 2.439, h-index: 167)
Cardiovascular Research     Hybrid Journal   (Followers: 11, SJR: 2.897, h-index: 175)
Cerebral Cortex     Hybrid Journal   (Followers: 40, SJR: 4.827, h-index: 192)
CESifo Economic Studies     Hybrid Journal   (Followers: 16, SJR: 0.501, h-index: 19)
Chemical Senses     Hybrid Journal   (Followers: 1, SJR: 1.436, h-index: 76)
Children and Schools     Hybrid Journal   (Followers: 6, SJR: 0.211, h-index: 18)
Chinese J. of Comparative Law     Hybrid Journal   (Followers: 3)
Chinese J. of Intl. Law     Hybrid Journal   (Followers: 21, SJR: 0.737, h-index: 11)
Chinese J. of Intl. Politics     Hybrid Journal   (Followers: 8, SJR: 1.238, h-index: 15)
Christian Bioethics: Non-Ecumenical Studies in Medical Morality     Hybrid Journal   (Followers: 11, SJR: 0.191, h-index: 8)
Classical Receptions J.     Hybrid Journal   (Followers: 20, SJR: 0.1, h-index: 3)
Clinical Infectious Diseases     Hybrid Journal   (Followers: 58, SJR: 4.742, h-index: 261)
Clinical Kidney J.     Open Access   (Followers: 4, SJR: 0.338, h-index: 19)
Community Development J.     Hybrid Journal   (Followers: 24, SJR: 0.47, h-index: 28)
Computer J.     Hybrid Journal   (Followers: 7, SJR: 0.371, h-index: 47)
Conservation Physiology     Open Access   (Followers: 2)
Contemporary Women's Writing     Hybrid Journal   (Followers: 11, SJR: 0.111, h-index: 3)
Contributions to Political Economy     Hybrid Journal   (Followers: 6, SJR: 0.313, h-index: 10)
Critical Values     Full-text available via subscription  
Current Legal Problems     Hybrid Journal   (Followers: 26)
Current Zoology     Full-text available via subscription   (SJR: 0.999, h-index: 20)
Database : The J. of Biological Databases and Curation     Open Access   (Followers: 11, SJR: 1.068, h-index: 24)
Digital Scholarship in the Humanities     Hybrid Journal   (Followers: 12)
Diplomatic History     Hybrid Journal   (Followers: 18, SJR: 0.296, h-index: 22)
DNA Research     Open Access   (Followers: 4, SJR: 2.42, h-index: 77)
Dynamics and Statistics of the Climate System     Open Access   (Followers: 3)
Early Music     Hybrid Journal   (Followers: 14, SJR: 0.124, h-index: 11)
Economic Policy     Hybrid Journal   (Followers: 59, SJR: 2.052, h-index: 52)
ELT J.     Hybrid Journal   (Followers: 25, SJR: 1.26, h-index: 23)
English Historical Review     Hybrid Journal   (Followers: 48, SJR: 0.311, h-index: 10)
English: J. of the English Association     Hybrid Journal   (Followers: 13, SJR: 0.144, h-index: 3)
Environmental Entomology     Full-text available via subscription   (Followers: 11, SJR: 0.791, h-index: 66)
Environmental Epigenetics     Open Access   (Followers: 1)
Environmental History     Hybrid Journal   (Followers: 26, SJR: 0.197, h-index: 25)
EP-Europace     Hybrid Journal   (Followers: 2, SJR: 2.201, h-index: 71)
Epidemiologic Reviews     Hybrid Journal   (Followers: 10, SJR: 3.917, h-index: 81)
ESHRE Monographs     Hybrid Journal  
Essays in Criticism     Hybrid Journal   (Followers: 16, SJR: 0.1, h-index: 6)
European Heart J.     Hybrid Journal   (Followers: 49, SJR: 6.997, h-index: 227)
European Heart J. - Cardiovascular Imaging     Hybrid Journal   (Followers: 9, SJR: 2.044, h-index: 58)
European Heart J. - Cardiovascular Pharmacotherapy     Full-text available via subscription   (Followers: 1)
European Heart J. - Quality of Care and Clinical Outcomes     Hybrid Journal  
European Heart J. Supplements     Hybrid Journal   (Followers: 8, SJR: 0.152, h-index: 31)
European J. of Cardio-Thoracic Surgery     Hybrid Journal   (Followers: 8, SJR: 1.568, h-index: 104)
European J. of Intl. Law     Hybrid Journal   (Followers: 153, SJR: 0.722, h-index: 38)
European J. of Orthodontics     Hybrid Journal   (Followers: 4, SJR: 1.09, h-index: 60)
European J. of Public Health     Hybrid Journal   (Followers: 22, SJR: 1.284, h-index: 64)
European Review of Agricultural Economics     Hybrid Journal   (Followers: 12, SJR: 1.549, h-index: 42)
European Review of Economic History     Hybrid Journal   (Followers: 28, SJR: 0.628, h-index: 24)
European Sociological Review     Hybrid Journal   (Followers: 40, SJR: 2.061, h-index: 53)
Evolution, Medicine, and Public Health     Open Access   (Followers: 11)
Family Practice     Hybrid Journal   (Followers: 11, SJR: 1.048, h-index: 77)
Fems Microbiology Ecology     Hybrid Journal   (Followers: 8, SJR: 1.687, h-index: 115)
Fems Microbiology Letters     Hybrid Journal   (Followers: 20, SJR: 1.126, h-index: 118)
Fems Microbiology Reviews     Hybrid Journal   (Followers: 25, SJR: 7.587, h-index: 150)
Fems Yeast Research     Hybrid Journal   (Followers: 13, SJR: 1.213, h-index: 66)
Foreign Policy Analysis     Hybrid Journal   (Followers: 21, SJR: 0.859, h-index: 10)
Forestry: An Intl. J. of Forest Research     Hybrid Journal   (Followers: 16, SJR: 0.903, h-index: 44)
Forum for Modern Language Studies     Hybrid Journal   (Followers: 6, SJR: 0.108, h-index: 6)
French History     Hybrid Journal   (Followers: 31, SJR: 0.123, h-index: 10)
French Studies     Hybrid Journal   (Followers: 19, SJR: 0.119, h-index: 7)
French Studies Bulletin     Hybrid Journal   (Followers: 10, SJR: 0.102, h-index: 3)
Gastroenterology Report     Open Access   (Followers: 2)
Genome Biology and Evolution     Open Access   (Followers: 9, SJR: 3.22, h-index: 39)
Geophysical J. Intl.     Hybrid Journal   (Followers: 34, SJR: 1.839, h-index: 119)
German History     Hybrid Journal   (Followers: 25, SJR: 0.437, h-index: 13)
GigaScience     Open Access   (Followers: 3)
Global Summitry     Hybrid Journal  
Glycobiology     Hybrid Journal   (Followers: 14, SJR: 1.692, h-index: 101)
Health and Social Work     Hybrid Journal   (Followers: 48, SJR: 0.505, h-index: 40)
Health Education Research     Hybrid Journal   (Followers: 12, SJR: 0.814, h-index: 80)
Health Policy and Planning     Hybrid Journal   (Followers: 19, SJR: 1.628, h-index: 66)
Health Promotion Intl.     Hybrid Journal   (Followers: 21, SJR: 0.664, h-index: 60)
History Workshop J.     Hybrid Journal   (Followers: 26, SJR: 0.313, h-index: 20)
Holocaust and Genocide Studies     Hybrid Journal   (Followers: 23, SJR: 0.115, h-index: 13)
Human Molecular Genetics     Hybrid Journal   (Followers: 9, SJR: 4.288, h-index: 233)
Human Reproduction     Hybrid Journal   (Followers: 78, SJR: 2.271, h-index: 179)
Human Reproduction Update     Hybrid Journal   (Followers: 18, SJR: 4.678, h-index: 128)
Human Rights Law Review     Hybrid Journal   (Followers: 59, SJR: 0.7, h-index: 21)
ICES J. of Marine Science: J. du Conseil     Hybrid Journal   (Followers: 53, SJR: 1.233, h-index: 88)
ICSID Review     Hybrid Journal   (Followers: 9)
ILAR J.     Hybrid Journal   (Followers: 1, SJR: 1.099, h-index: 51)
IMA J. of Applied Mathematics     Hybrid Journal   (SJR: 0.329, h-index: 26)
IMA J. of Management Mathematics     Hybrid Journal   (Followers: 2, SJR: 0.351, h-index: 20)
IMA J. of Mathematical Control and Information     Hybrid Journal   (Followers: 2, SJR: 0.661, h-index: 28)
IMA J. of Numerical Analysis - advance access     Hybrid Journal   (SJR: 2.032, h-index: 44)
Industrial and Corporate Change     Hybrid Journal   (Followers: 8, SJR: 1.37, h-index: 81)
Industrial Law J.     Hybrid Journal   (Followers: 29, SJR: 0.184, h-index: 15)
Information and Inference     Free  
Integrative and Comparative Biology     Hybrid Journal   (Followers: 8, SJR: 1.911, h-index: 90)
Interacting with Computers     Hybrid Journal   (Followers: 10, SJR: 0.529, h-index: 59)
Interactive CardioVascular and Thoracic Surgery     Hybrid Journal   (Followers: 5, SJR: 0.743, h-index: 35)
Intl. Affairs     Hybrid Journal   (Followers: 51, SJR: 1.264, h-index: 53)
Intl. Data Privacy Law     Hybrid Journal   (Followers: 28)
Intl. Health     Hybrid Journal   (Followers: 5, SJR: 0.835, h-index: 15)
Intl. Immunology     Hybrid Journal   (Followers: 3, SJR: 1.613, h-index: 111)
Intl. J. for Quality in Health Care     Hybrid Journal   (Followers: 32, SJR: 1.593, h-index: 69)
Intl. J. of Constitutional Law     Hybrid Journal   (Followers: 59, SJR: 0.613, h-index: 19)
Intl. J. of Epidemiology     Hybrid Journal   (Followers: 134, SJR: 4.381, h-index: 145)
Intl. J. of Law and Information Technology     Hybrid Journal   (Followers: 4, SJR: 0.247, h-index: 8)
Intl. J. of Law, Policy and the Family     Hybrid Journal   (Followers: 29, SJR: 0.307, h-index: 15)
Intl. J. of Lexicography     Hybrid Journal   (Followers: 8, SJR: 0.404, h-index: 18)
Intl. J. of Low-Carbon Technologies     Open Access   (Followers: 1, SJR: 0.457, h-index: 12)
Intl. J. of Neuropsychopharmacology     Open Access   (Followers: 3, SJR: 1.69, h-index: 79)
Intl. J. of Public Opinion Research     Hybrid Journal   (Followers: 9, SJR: 0.906, h-index: 33)
Intl. J. of Refugee Law     Hybrid Journal   (Followers: 32, SJR: 0.231, h-index: 21)
Intl. J. of Transitional Justice     Hybrid Journal   (Followers: 13, SJR: 0.833, h-index: 12)
Intl. Mathematics Research Notices     Hybrid Journal   (Followers: 1, SJR: 2.052, h-index: 42)
Intl. Political Sociology     Hybrid Journal   (Followers: 31, SJR: 1.339, h-index: 19)
Intl. Relations of the Asia-Pacific     Hybrid Journal   (Followers: 17, SJR: 0.539, h-index: 17)
Intl. Studies Perspectives     Hybrid Journal   (Followers: 7, SJR: 0.998, h-index: 28)
Intl. Studies Quarterly     Hybrid Journal   (Followers: 38, SJR: 2.184, h-index: 68)
Intl. Studies Review     Hybrid Journal   (Followers: 18, SJR: 0.783, h-index: 38)
ISLE: Interdisciplinary Studies in Literature and Environment     Hybrid Journal   (Followers: 1, SJR: 0.155, h-index: 4)
ITNOW     Hybrid Journal   (Followers: 2, SJR: 0.102, h-index: 4)
J. of African Economies     Hybrid Journal   (Followers: 15, SJR: 0.647, h-index: 30)
J. of American History     Hybrid Journal   (Followers: 40, SJR: 0.286, h-index: 34)
J. of Analytical Toxicology     Hybrid Journal   (Followers: 13, SJR: 1.038, h-index: 60)
J. of Antimicrobial Chemotherapy     Hybrid Journal   (Followers: 12, SJR: 2.157, h-index: 149)
J. of Antitrust Enforcement     Hybrid Journal   (Followers: 1)
J. of Applied Poultry Research     Hybrid Journal   (Followers: 3, SJR: 0.563, h-index: 43)
J. of Biochemistry     Hybrid Journal   (Followers: 43, SJR: 1.341, h-index: 96)
J. of Chromatographic Science     Hybrid Journal   (Followers: 16, SJR: 0.448, h-index: 42)
J. of Church and State     Hybrid Journal   (Followers: 11, SJR: 0.167, h-index: 11)
J. of Competition Law and Economics     Hybrid Journal   (Followers: 34, SJR: 0.442, h-index: 16)
J. of Complex Networks     Hybrid Journal   (Followers: 1, SJR: 1.165, h-index: 5)
J. of Conflict and Security Law     Hybrid Journal   (Followers: 12, SJR: 0.196, h-index: 15)
J. of Consumer Research     Full-text available via subscription   (Followers: 41, SJR: 4.896, h-index: 121)
J. of Crohn's and Colitis     Hybrid Journal   (Followers: 10, SJR: 1.543, h-index: 37)
J. of Cybersecurity     Hybrid Journal   (Followers: 3)
J. of Deaf Studies and Deaf Education     Hybrid Journal   (Followers: 9, SJR: 0.69, h-index: 36)
J. of Design History     Hybrid Journal   (Followers: 15, SJR: 0.166, h-index: 14)
J. of Economic Entomology     Full-text available via subscription   (Followers: 6, SJR: 0.894, h-index: 76)
J. of Economic Geography     Hybrid Journal   (Followers: 39, SJR: 2.909, h-index: 69)
J. of Environmental Law     Hybrid Journal   (Followers: 23, SJR: 0.457, h-index: 20)
J. of European Competition Law & Practice     Hybrid Journal   (Followers: 18)
J. of Experimental Botany     Hybrid Journal   (Followers: 14, SJR: 2.798, h-index: 163)
J. of Financial Econometrics     Hybrid Journal   (Followers: 21, SJR: 1.314, h-index: 27)
J. of Global Security Studies     Hybrid Journal   (Followers: 3)
J. of Heredity     Hybrid Journal   (Followers: 4, SJR: 1.024, h-index: 76)
J. of Hindu Studies     Hybrid Journal   (Followers: 7, SJR: 0.186, h-index: 3)
J. of Hip Preservation Surgery     Open Access  
J. of Human Rights Practice     Hybrid Journal   (Followers: 20, SJR: 0.399, h-index: 10)
J. of Infectious Diseases     Hybrid Journal   (Followers: 40, SJR: 4, h-index: 209)
J. of Insect Science     Open Access   (Followers: 9, SJR: 0.388, h-index: 31)

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Journal Cover Cerebral Cortex
  [SJR: 4.827]   [H-I: 192]   [40 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1047-3211 - ISSN (Online) 1460-2199
   Published by Oxford University Press Homepage  [370 journals]
  • Neuronal Activity, TGFβ-Signaling and Unpredictable Chronic Stress
           Modulate Transcription of Gadd45 Family Members and DNA Methylation in the
           Hippocampus
    • Authors: Grassi D; Franz H, Vezzali R, et al.
      First page: 4166
      Abstract: AbstractNeuronal activity is altered in several neurological and psychiatric diseases. Upon depolarization not only neurotransmitters are released but also cytokines and other activators of signaling cascades. Unraveling their complex implication in transcriptional control in receiving cells will contribute to understand specific central nervous system (CNS) pathologies and will be of therapeutically interest. In this study we depolarized mature hippocampal neurons in vitro using KCl and revealed increased release not only of brain-derived neurotrophic factor (BDNF) but also of transforming growth factor beta (TGFB). Neuronal activity together with BDNF and TGFB controls transcription of DNA modifying enzymes specifically members of the DNA-damage-inducible (Gadd) family, Gadd45a, Gadd45b, and Gadd45g. MeDIP followed by massive parallel sequencing and transcriptome analyses revealed less DNA methylation upon KCl treatment. Psychiatric disorder-related genes, namely Tshz1, Foxn3, Jarid2, Per1, Map3k5, and Arc are transcriptionally activated and demethylated upon neuronal activation. To analyze whether misexpression of Gadd45 family members are associated with psychiatric diseases, we applied unpredictable chronic mild stress (UCMS) as established model for depression to mice. UCMS led to reduced expression of Gadd45 family members. Taken together, our data demonstrate that Gadd45 family members are new putative targets for UCMS treatments.
      PubDate: 2017-04-21
      DOI: 10.1093/cercor/bhx095
       
  • The Endogenous Stress Hormone CRH Modulates Excitatory Transmission and
           Network Physiology in Hippocampus
    • Authors: Gunn BG; Cox CD, Chen YY, et al.
      First page: 4182
      Abstract: AbstractMemory is strongly influenced by stress but underlying mechanisms are unknown. Here, we used electrophysiology, neuroanatomy, and network simulations to probe the role of the endogenous, stress-related neuropeptide corticotropin-releasing hormone (CRH) in modulating hippocampal function. We focused on neuronal excitability and the incidence of sharp waves (SPWs), a form of intrinsic network activity associated with memory consolidation. Specifically, we blocked endogenous CRH using 2 chemically distinct antagonists of the principal hippocampal CRH receptor, CRHR1. The antagonists caused a modest reduction of spontaneous excitatory transmission onto CA3 pyramidal cells, mediated, in part by effects on IAHP. This was accompanied by a decrease in the incidence but not amplitude of SPWs, indicating that the synaptic actions of CRH are sufficient to alter the output of a complex hippocampal network. A biophysical model of CA3 described how local actions of CRH produce macroscopic consequences including the observed changes in SPWs. Collectively, the results provide a first demonstration of the manner in which subtle synaptic effects of an endogenously released neuropeptide influence hippocampal network level operations and, in the case of CRH, may contribute to the effects of acute stress on memory.
      PubDate: 2017-04-28
      DOI: 10.1093/cercor/bhx103
       
  • Mapping Domain-Selective and Counterpointed Domain-General Higher
           Cognitive Functions in the Lateral Parietal Cortex: Evidence from fMRI
           Comparisons of Difficulty-Varying Semantic Versus Visuo-Spatial Tasks, and
           Functional Connectivity Analyses
    • Authors: Humphreys GF; Lambon Ralph MA.
      First page: 4199
      Abstract: AbstractNumerous cognitive domains have been associated with the lateral parietal cortex, yet how these disparate functions are packed into this region remains unclear. Whilst areas within the dorsal and the ventral parietal cortex (DPC and VPC) show differential function, there is considerable disagreement as to what these functions might be. Studies focussed on individual domains have plotted out variations of function across the region. Direct cross-domain comparisons are rare yet, when they have been undertaken, at least some regions (particularly the intraparietal sulcus [IPS] and core angular gyrus [AG]) appear to have contrastive domain-general qualities. In order to pursue this parietal puzzle, this study utilized both functional and resting-state magnetic resonance imaging to investigate a potential unifying neurocomputational framework—in which both domain general as well as domain-selective regions arise from differential patterns of connectivity into subregions of the lateral parietal cortex. Specifically we found that, consistent with their contrastive patterns of functional connectivity, subregions of DPC (anterior IPS) and VPC (AG) exhibit counterpointed functions sensitive to task/item-difficulty irrespective of cognitive domain. We propose that these regions serve as top-down executively penetrated and automatic bottom-up domain-general buffers of active information, respectively. In contrast, other parietal and nonparietal regions are tuned toward specific domains.
      PubDate: 2017-05-02
      DOI: 10.1093/cercor/bhx107
       
  • Changes in the Proliferative Program Limit Astrocyte Homeostasis in the
           Aged Post-Traumatic Murine Cerebral Cortex
    • Authors: Heimann G; Canhos LL, Frik J, et al.
      First page: 4213
      Abstract: AbstractAging leads to adverse outcomes after traumatic brain injury. The mechanisms underlying these defects, however, are not yet clear. In this study, we found that astrocytes in the aged post-traumatic cerebral cortex develop a significantly reduced proliferative response, resulting in reduced astrocyte numbers in the penumbra. Moreover, experiments of reactive astrocytes in vitro reveal that their diminished proliferation is due to an age-related switch in the division mode with reduced cell-cycle re-entry rather than changes in cell-cycle length. Notably, reactive astrocytes in vivo and in vitro become refractory to stimuli increasing their proliferation during aging, such as Sonic hedgehog signaling. These data demonstrate for the first time that age-dependent, most likely intrinsic changes in the proliferative program of reactive astrocytes result in their severely hampered proliferative response to traumatic injury thereby affecting astrocyte homeostasis.
      PubDate: 2017-05-04
      DOI: 10.1093/cercor/bhx112
       
  • Decomposing Tool-Action Observation: A Stereo-EEG Study
    • Authors: Caruana FF; Avanzini PP, Mai RR, et al.
      First page: 4229
      Abstract: AbstractA description of the spatiotemporal dynamics of human cortical activity during cognitive tasks is a fundamental goal of neuroscience. In the present study, we employed stereo-EEG in order to assess the neural activity during tool-action observation. We recorded from 49 epileptic patients (5502 leads) implanted with intracerebral electrodes, while they observed tool and hand actions. We deconstructed actions into 3 events—video onset, action onset, and tool-object contact—and assessed how different brain regions respond to these events. Video onset, with actions not yet visible, recruited only visual areas. Aligning the responses at action onset, yielded activity in the parietal-frontal manipulation circuit and, selectively for tool actions, in the left anterior supramarginal gyrus (aSMG). Finally, by aligning to the tool-object contact that signals the achievement of the main goal of the observed action, activations were found in SII and dorsal premotor cortex. In conclusion, our data show that during tool-action observation, in addition to the general action observation network there is a selective activation of aSMG, which exhibits internally different patterns of responsiveness. In addition, neural responses selective for the contact between the tool and the object were also observed.
      PubDate: 2017-05-19
      DOI: 10.1093/cercor/bhx124
       
  • Relationship Between Synaptic AMPAR and Spine Dynamics: Impairments in the
           FXS Mouse
    • Authors: Suresh A; Dunaevsky A.
      First page: 4244
      Abstract: AbstractStructural dynamics of dendritic spines are important for memory and learning and are impaired in neurodevelopmental disorders such as fragile X syndrome. Spine dynamics are regulated by activity-dependent mechanisms that involve modulation of AMPA receptors (AMPAR); however, the relationship between AMPAR and spine dynamics in vivo and how these are altered in FXS mouse model is not known. Here, we tracked AMPAR and spines over multiple days in vivo in the cortex and found that dendritic spines in the fmr1 KO mouse were denser, smaller, had higher turnover rates and contained less sGluA2 compared to littermate controls. Although, KO spines maintained the relationship between AMPAR and spine stability, AMPAR levels in the KO were more dynamic with larger proportion of spines showing multiple dynamic events of AMPAR. Directional changes in sGluA2 were also observed in newly formed and eliminated spines, with KO spines displaying greater loss of AMPAR before elimination. Thus, we demonstrate that AMPAR levels within spines not are only continuously dynamic, but are also predictive of spine behavior, with impairments observed in the fmr1 KO mice.
      PubDate: 2017-05-24
      DOI: 10.1093/cercor/bhx128
       
  • Dissociable Roles of Cerebral μ-Opioid and Type 2 Dopamine Receptors in
           Vicarious Pain: A Combined PET–fMRI Study
    • Authors: Karjalainen T; Karlsson HK, Lahnakoski JM, et al.
      First page: 4257
      Abstract: AbstractNeuroimaging studies have shown that seeing others in pain activates brain regions that are involved in first-hand pain, suggesting that shared neuromolecular pathways support processing of first-hand and vicarious pain. We tested whether the dopamine and opioid neurotransmitter systems involved in nociceptive processing also contribute to vicarious pain experience. We used in vivo positron emission tomography to quantify type 2 dopamine and μ-opioid receptor (D2R and MOR, respectively) availabilities in brains of 35 subjects. During functional magnetic resonance imaging, the subjects watched short movie clips depicting persons in painful and painless situations. Painful scenes activated pain-responsive brain regions including anterior insulae, thalamus and secondary somatosensory cortices, as well as posterior superior temporal sulci. MOR availability correlated negatively with the haemodynamic responses during painful scenes in anterior and posterior insulae, thalamus, secondary and primary somatosensory cortices, primary motor cortex, and superior temporal sulci. MOR availability correlated positively with orbitofrontal haemodynamic responses during painful scenes. D2R availability was not correlated with the haemodynamic responses in any brain region. These results suggest that the opioid system contributes to neural processing of vicarious pain, and that interindividual differences in opioidergic system could explain why some individuals react more strongly than others to seeing pain.
      PubDate: 2017-05-24
      DOI: 10.1093/cercor/bhx129
       
  • Structural Covariance Networks in Children with Autism or ADHD
    • Authors: Bethlehem RI; Romero-Garcia RR, Mak EE, et al.
      First page: 4267
      Abstract: AbstractBackgroundWhile autism and attention-deficit/hyperactivity disorder (ADHD) are considered distinct conditions from a diagnostic perspective, clinically they share some phenotypic features and have high comorbidity. Regardless, most studies have focused on only one condition, with considerable heterogeneity in their results. Taking a dual-condition approach might help elucidate shared and distinct neural characteristics.MethodGraph theory was used to analyse topological properties of structural covariance networks across both conditions and relative to a neurotypical (NT; n = 87) group using data from the ABIDE (autism; n = 62) and ADHD-200 datasets (ADHD; n = 69). Regional cortical thickness was used to construct the structural covariance networks. This was analysed in a theoretical framework examining potential differences in long and short-range connectivity, with a specific focus on relation between central graph measures and cortical thickness.ResultsWe found convergence between autism and ADHD, where both conditions show an overall decrease in CT covariance with increased Euclidean distance between centroids compared with a NT population. The 2 conditions also show divergence. Namely, there is less modular overlap between the 2 conditions than there is between each condition and the NT group. The ADHD group also showed reduced cortical thickness and lower degree in hub regions than the autism group. Lastly, the ADHD group also showed reduced wiring costs compared with the autism groups.ConclusionsOur results indicate a need for taking an integrated approach when considering highly comorbid conditions such as autism and ADHD. Furthermore, autism and ADHD both showed alterations in the relation between inter-regional covariance and centroid distance, where both groups show a steeper decline in covariance as a function of distance. The 2 groups also diverge on modular organization, cortical thickness of hub regions and wiring cost of the covariance network. Thus, on some network features the groups are distinct, yet on others there is convergence.
      PubDate: 2017-06-13
      DOI: 10.1093/cercor/bhx135
       
  • Attention Selectively Reshapes the Geometry of Distributed Semantic
           Representation
    • Authors: Nastase SA; Connolly AC, Oosterhof NN, et al.
      First page: 4277
      Abstract: AbstractHumans prioritize different semantic qualities of a complex stimulus depending on their behavioral goals. These semantic features are encoded in distributed neural populations, yet it is unclear how attention might operate across these distributed representations. To address this, we presented participants with naturalistic video clips of animals behaving in their natural environments while the participants attended to either behavior or taxonomy. We used models of representational geometry to investigate how attentional allocation affects the distributed neural representation of animal behavior and taxonomy. Attending to animal behavior transiently increased the discriminability of distributed population codes for observed actions in anterior intraparietal, pericentral, and ventral temporal cortices. Attending to animal taxonomy while viewing the same stimuli increased the discriminability of distributed animal category representations in ventral temporal cortex. For both tasks, attention selectively enhanced the discriminability of response patterns along behaviorally relevant dimensions. These findings suggest that behavioral goals alter how the brain extracts semantic features from the visual world. Attention effectively disentangles population responses for downstream read-out by sculpting representational geometry in late-stage perceptual areas.
      PubDate: 2017-06-07
      DOI: 10.1093/cercor/bhx138
       
  • Longitudinal Study of White Matter Development and Outcomes in Children
           Born Very Preterm
    • Authors: Young JM; Morgan BR, Whyte HA, et al.
      Abstract: AbstractIdentifying trajectories of early white matter development is important for understanding atypical brain development and impaired functional outcomes in children born very preterm (<32 weeks gestational age [GA]). In this study, 161 diffusion images were acquired in children born very preterm (median GA: 29 weeks) shortly following birth (75), term-equivalent (39), 2 years (18), and 4 years of age (29). Diffusion tensors were computed to obtain measures of fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD), which were aligned and averaged. A paediatric atlas was applied to obtain diffusion metrics within 12 white matter tracts. Developmental trajectories across time points demonstrated age-related changes which plateaued between term-equivalent and 2 years of age in the majority of posterior tracts and between 2 and 4 years of age in anterior tracts. Between preterm and term-equivalent scans, FA rates of change were slower in anterior than posterior tracts. Partial least squares analyses revealed associations between slower MD and RD rates of change within the external and internal capsule with lower intelligence quotients and language scores at 4 years of age. These results uniquely demonstrate early white matter development and its linkage to cognitive functions.
      PubDate: 2016-09-03
       
  • Variant BDNF-Val66Met Polymorphism is Associated with Layer-Specific
           Alterations in GABAergic Innervation of Pyramidal Neurons, Elevated
           Anxiety and Reduced Vulnerability of Adolescent Male Mice to
           Activity-Based Anorexia
    • Authors: Chen Y; Surgent O, Rana BS, et al.
      Abstract: AbstractPreviously, we determined that rodents’ vulnerability to food restriction (FR)-evoked wheel running during adolescence (activity-based anorexia, ABA) is associated with failures to increase GABAergic innervation of hippocampal and medial prefrontal pyramidal neurons. Since brain-derived neurotrophic factor (BDNF) promotes GABAergic synaptogenesis, we hypothesized that individual differences in this vulnerability may arise from differences in the link between BDNF bioavailability and FR-evoked wheel running. We tested this hypothesis in male BDNF-Val66Met knock-in mice (BDNFMet/Met), known for reduction in the activity-dependent BDNF secretion and elevated anxiety-like behaviors. We found that 1) in the absence of FR or a wheel (i.e., control), BDNFMet/Met mice are more anxious than wild-type (WT) littermates, 2) electron microscopically verified GABAergic innervations of pyramidal neurons of BDNFMet/Met mice are reduced at distal dendrites in hippocampal CA1 and medial prefrontal cortex, 3) following ABA, WT mice exhibit anxiety equal to those of the BDNFMet/Met mice and have lost GABAergic innervation along distal dendrites, 4) BDNFMet/Met mice show blunted ABA vulnerability, and 5) unexpectedly, GABAergic innervation is higher at somata of BDNFMet/Met mice than of WT. We conclude that lamina-specific GABAergic inhibition is important for regulating anxiety, whether arising from environmental stress, such as food deprivation, or genetically, such as BDNFMet/Met single nucleotide polymorphism.
      PubDate: 2016-08-29
       
  • At a Single Glance: Fast Periodic Visual Stimulation Uncovers the
           Spatio-Temporal Dynamics of Brief Facial Expression Changes in the Human
           Brain
    • Authors: Dzhelyova M; Jacques C, Rossion B.
      Abstract: AbstractDetecting brief changes of facial expression is vital for social communication. Yet, how reliably, how fast these changes are detected and how long they are processed in the human brain remain unknown. High-density electroencephalogram (EEG) was recorded in 18 participants presented with a neutral-expression face at a rate of 5.88 Hz (F) for 80 s. Every five faces, the face changed expression to fear, disgust or happiness (different stimulation sequences). The resulting 1.18 Hz (F/5) EEG response and its harmonics objectively indexed detection of a brief change of facial expression. This response was recorded in every participant in a few minutes but was largely reduced for inverted faces, indicating that it reflects high-level processes. Although this response focused on occipito-temporal sites, different expression changes evoked reliably distinct topographical maps, pointing to partly distinct neural generators. These effects were also observed at a faster 12 Hz frequency rate and a lower ratio of expression change (1/9). Time-domain analysis showed that a brief change of expression inserted in a dynamic stimulation sequence elicits specific occipito-temporal responses between 100 and 310 ms, indicating a rapid change detection process followed by a long integration period of facial expression information in the human brain.
      PubDate: 2016-08-29
       
  • Prefrontal Cortical GABAergic Dysfunction Contributes to Aberrant UP-State
           Duration in APP Knockout Mice
    • Authors: Huo Q; Chen M, He Q, et al.
      Abstract: AbstractGenetic and biochemical studies have focused on the role of amyloid β protein in the pathogenesis of Alzheimer's disease. In comparison, the physiological roles of its precursor protein, amyloid precursor protein (APP), in synaptic and network activity is less well studied. Using an APP knockout (APP−/−) mouse model, we show that the duration of UP state, which is a key feature of cortical synaptic integration occurring predominantly during slow-wave sleep, is significantly increased in the prefrontal cortex (PFC) in the absence of APP. This was accompanied by a specific reduction in the glutamine synthetase and tissue GABA content and sequential upregulation in the levels of GABABR expression. Pharmacological reinforcement of GABA signaling by application of either a GABA uptake inhibitor or an agonist of GABABR rescued the abnormality of UP-state duration and the former rescues altered GABABR expression as well. In addition to revealing an essential role of APP in the regulation of PFC network function, this study evidences the viability of GABA signaling pathway and its receptors, especially GABABRs, as a target for the treatment of aberrant neural network activity and thus information processing.
      PubDate: 2016-08-23
       
  • Spatial Mechanisms within the Dorsal Visual Pathway Contribute to the
           Configural Processing of Faces
    • Authors: Zachariou V; Nikas CV, Safiullah ZN, et al.
      Abstract: AbstractHuman face recognition is often attributed to configural processing; namely, processing the spatial relationships among the features of a face. If configural processing depends on fine-grained spatial information, do visuospatial mechanisms within the dorsal visual pathway contribute to this process' We explored this question in human adults using functional magnetic resonance imaging and transcranial magnetic stimulation (TMS) in a same-different face detection task. Within localized, spatial-processing regions of the posterior parietal cortex, configural face differences led to significantly stronger activation compared to featural face differences, and the magnitude of this activation correlated with behavioral performance. In addition, detection of configural relative to featural face differences led to significantly stronger functional connectivity between the right FFA and the spatial processing regions of the dorsal stream, whereas detection of featural relative to configural face differences led to stronger functional connectivity between the right FFA and left FFA. Critically, TMS centered on these parietal regions impaired performance on configural but not featural face difference detections. We conclude that spatial mechanisms within the dorsal visual pathway contribute to the configural processing of facial features and, more broadly, that the dorsal stream may contribute to the veridical perception of faces.
      PubDate: 2016-08-13
       
  • Temporal Evolution of Brain Functional Connectivity Metrics: Could 7 Min
           of Rest be Enough'
    • Authors: Tomasi DG; Shokri-Kojori E, Volkow ND.
      Abstract: AbstractUnaccounted temporal dynamics of resting-state functional connectivity (FC) metrics challenges their potential as biomarkers for clinical applications in neuroscience. Here we studied the scan time required to reach stable values for various FC metrics including seed-voxel correlations and spatial independent component analyses (sICA), and for the local functional connectivity density (lFCD), a graph theory metric. By increasing the number of time points included in the analysis, we assessed the effects of scan time on convergence of accuracy, sensitivity, specificity, reproducibility, and reliability of these FC metrics. The necessary scan time to attenuate the effects of the temporal dynamics by 80% varied across connectivity metrics and was shorter for lFCD (7 min) than for FC (11 min) or for sICA (10 min). Findings suggest that the scan time required to achieve stable FC is metric-dependent, with lFCD being the most resilient metric to the effects of temporal dynamics. Thus, the lFCD metric could be particularly useful for pediatric and patient populations who may not tolerate long scans.
      PubDate: 2016-08-11
       
  • Componential Network for the Recognition of Tool-Associated Actions:
           
    • Authors: Martin M; Dressing A, Bormann T, et al.
      Abstract: AbstractThe study aimed to elucidate areas involved in recognizing tool-associated actions, and to characterize the relationship between recognition and active performance of tool use.We performed voxel-based lesion-symptom mapping in a prospective cohort of 98 acute left-hemisphere ischemic stroke patients (68 male, age mean ± standard deviation, 65 ± 13 years; examination 4.4 ± 2 days post-stroke). In a video-based test, patients distinguished correct tool-related actions from actions with spatio-temporal (incorrect grip, kinematics, or tool orientation) or conceptual errors (incorrect tool–recipient matching, e.g., spreading jam on toast with a paintbrush). Moreover, spatio-temporal and conceptual errors were determined during actual tool use.Deficient spatio-temporal error discrimination followed lesions within a dorsal network in which the inferior parietal lobule (IPL) and the lateral temporal cortex (sLTC) were specifically relevant for assessing functional hand postures and kinematics, respectively. Conversely, impaired recognition of conceptual errors resulted from damage to ventral stream regions including anterior temporal lobe. Furthermore, LTC and IPL lesions impacted differently on action recognition and active tool use, respectively.In summary, recognition of tool-associated actions relies on a componential network. Our study particularly highlights the dissociable roles of LTC and IPL for the recognition of action kinematics and functional hand postures, respectively.
      PubDate: 2016-08-04
       
  • fMRI-based Multivariate Pattern Analyses Reveal Imagery Modality and
           Imagery Content Specific Representations in Primary Somatosensory, Motor
           and Auditory Cortices
    • Authors: de Borst AW; de Gelder B.
      Abstract: AbstractPrevious studies have shown that the early visual cortex contains content-specific representations of stimuli during visual imagery, and that these representational patterns of imagery content have a perceptual basis. To date, there is little evidence for the presence of a similar organization in the auditory and tactile domains. Using fMRI-based multivariate pattern analyses we showed that primary somatosensory, auditory, motor, and visual cortices are discriminative for imagery of touch versus sound. In the somatosensory, motor and visual cortices the imagery modality discriminative patterns were similar to perception modality discriminative patterns, suggesting that top-down modulations in these regions rely on similar neural representations as bottom-up perceptual processes. Moreover, we found evidence for content-specific representations of the stimuli during auditory imagery in the primary somatosensory and primary motor cortices. Both the imagined emotions and the imagined identities of the auditory stimuli could be successfully classified in these regions.
      PubDate: 2016-07-29
       
  • Modulating Reward Induces Differential Neurocognitive Approaches to
           Sustained Attention
    • Authors: Esterman M; Poole V, Liu G, et al.
      Abstract: AbstractReward and motivation have powerful effects on cognition and brain activity, yet it remains unclear how they affect sustained cognitive performance. We have recently shown that a variety of motivators improve accuracy and reduce variability during sustained attention. In the current study, we investigate how neural activity in task-positive networks supports these sustained attention improvements. Participants performed the gradual-onset continuous performance task with alternating motivated (rewarded) and unmotivated (unrewarded) blocks. During motivated blocks, we observed increased sustained neural recruitment of task-positive regions, which interacted with fluctuations in task performance. Specifically, during motivated blocks, participants recruited these regions in preparation for upcoming targets, and this activation predicted accuracy. In contrast, during unmotivated blocks, no such advanced preparation was observed. Furthermore, during motivated blocks, participants had similar activation levels during both optimal (in-the-zone) and suboptimal (out-of-the-zone) epochs of performance. In contrast, during unmotivated blocks, task-positive regions were only engaged to a similar degree as motivated blocks during suboptimal (out-of-the-zone) periods. These data support a framework in which motivated individuals act as “cognitive investors,” engaging task-positive resources proactively and consistently during sustaining attention. When unmotivated, however, the same individuals act as “cognitive misers,” engaging maximal task-positive resources only during periods of struggle.
      PubDate: 2016-07-29
       
  • Synaptic Adhesion Molecules Regulate the Integration of New Granule
           Neurons in the Postnatal Mouse Hippocampus and their Impact on Spatial
           Memory
    • Authors: Krzisch M; Fülling C, Jabinet L, et al.
      Abstract: AbstractPostnatal hippocampal neurogenesis induces network remodeling and may participate to mechanisms of learning. In turn, the maturation and survival of newborn neurons is regulated by their activity. Here, we tested the effect of a cell-autonomous overexpression of synaptic adhesion molecules on the maturation and survival of neurons born postnatally and on hippocampal-dependent memory performances. Families of adhesion molecules are known to induce pre- and post-synaptic assembly. Using viral targeting, we overexpressed three different synaptic adhesion molecules, SynCAM1, Neuroligin-1B and Neuroligin-2A in newborn neurons in the dentate gyrus of 7- to 9-week-old mice. We found that SynCAM1 increased the morphological maturation of dendritic spines and mossy fiber terminals while Neuroligin-1B increased spine density. In contrast, Neuroligin-2A increased both spine density and size as well as GABAergic innervation and resulted in a drastic increase of neuronal survival. Surprisingly, despite increased neurogenesis, mice overexpressing Neuroligin-2A in new neurons showed decreased memory performances in a Morris water maze task. These results indicate that the cell-autonomous overexpression of synaptic adhesion molecules can enhance different aspects of synapse formation on new neurons and increase their survival. Furthermore, they suggest that the mechanisms by which new neurons integrate in the postnatal hippocampus conditions their functional implication in learning and memory.
      PubDate: 2016-07-29
       
  • Dissociable Fronto-Operculum-Insula Control Signals for Anticipation and
           Detection of Inhibitory Sensory Cue
    • Authors: Cai W; Chen T, Ide JS, et al.
      Abstract: AbstractThe ability to anticipate and detect behaviorally salient stimuli is important for virtually all adaptive behaviors, including inhibitory control that requires the withholding of prepotent responses when instructed by external cues. Although right fronto-operculum-insula (FOI), encompassing the anterior insular cortex (rAI) and inferior frontal cortex (rIFC), involvement in inhibitory control is well established, little is known about signaling mechanisms underlying their differential roles in detection and anticipation of salient inhibitory cues. Here we use 2 independent functional magnetic resonance imaging data sets to investigate dynamic causal interactions of the rAI and rIFC, with sensory cortex during detection and anticipation of inhibitory cues. Across 2 different experiments involving auditory and visual inhibitory cues, we demonstrate that primary sensory cortex has a stronger causal influence on rAI than on rIFC, suggesting a greater role for the rAI in detection of salient inhibitory cues. Crucially, a Bayesian prediction model of subjective trial-by-trial changes in inhibitory cue anticipation revealed that the strength of causal influences from rIFC to rAI increased significantly on trials in which participants had higher anticipation of inhibitory cues. Together, these results demonstrate the dissociable bottom-up and top-down roles of distinct FOI regions in detection and anticipation of behaviorally salient cues across multiple sensory modalities.
      PubDate: 2016-07-29
       
  • Brain Activity and Functional Connectivity Associated with Hypnosis
    • Authors: Jiang H; White MP, Greicius MD, et al.
      Abstract: AbstractHypnosis has proven clinical utility, yet changes in brain activity underlying the hypnotic state have not yet been fully identified. Previous research suggests that hypnosis is associated with decreased default mode network (DMN) activity and that high hypnotizability is associated with greater functional connectivity between the executive control network (ECN) and the salience network (SN). We used functional magnetic resonance imaging to investigate activity and functional connectivity among these three networks in hypnosis. We selected 57 of 545 healthy subjects with very high or low hypnotizability using two hypnotizability scales. All subjects underwent four conditions in the scanner: rest, memory retrieval, and two different hypnosis experiences guided by standard pre-recorded instructions in counterbalanced order. Seeds for the ECN, SN, and DMN were left and right dorsolateral prefrontal cortex, dorsal anterior cingulate cortex (dACC), and posterior cingulate cortex (PCC), respectively. During hypnosis there was reduced activity in the dACC, increased functional connectivity between the dorsolateral prefrontal cortex (DLPFC;ECN) and the insula in the SN, and reduced connectivity between the ECN (DLPFC) and the DMN (PCC). These changes in neural activity underlie the focused attention, enhanced somatic and emotional control, and lack of self-consciousness that characterizes hypnosis.
      PubDate: 2016-07-27
       
  • The Left, The Better: White-Matter Brain Integrity Predicts Foreign
           Language Imitation Ability
    • Authors: Vaquero L; Rodríguez-Fornells A, Reiterer SM.
      Abstract: AbstractSpeech imitation is crucial for language acquisition and second-language learning. Interestingly, large individual differences regarding the ability in imitating foreign-language sounds have been observed. The origin of this interindividual diversity remains unknown, although it might be partially explained by structural predispositions. Here we correlated white-matter structural properties of the arcuate fasciculus (AF) with the performance of 52 German-speakers in a Hindi sentence- and word-imitation task. First, a manual reconstruction was performed, permitting us to extract the mean values along the three branches of the AF. We found that a larger lateralization of the AF volume toward the left hemisphere predicted the performance of our participants in the imitation task. Second, an automatic reconstruction was carried out, allowing us to localize the specific region within the AF that exhibited the largest correlation with foreign language imitation. Results of this reconstruction also showed a left lateralization trend: greater fractional anisotropy values in the anterior half of the left AF correlated with the performance in the Hindi-imitation task. From the best of our knowledge, this is the first time that foreign language imitation aptitude is tested using a more ecological imitation task and correlated with DTI tractography, using both a manual and an automatic method.
      PubDate: 2016-07-26
       
  • Rostro-caudal Architecture of the Frontal Lobes in Humans
    • Authors: Thiebaut de Schotten M; Urbanski M, Batrancourt B, et al.
      Abstract: AbstractThe nature of the inputs and outputs of a brain region defines its functional specialization. The frontal portion of the brain is essential for goal-directed behaviors, however, the biological basis for its functional organization is unknown. Here, exploring structural connectomic properties, we delineated 12 frontal areas, defined by the pattern of their white matter connections. This result was highly reproducible across neuroimaging centers, acquisition parameters, and participants. These areas corresponded to regions functionally engaged in specific tasks, organized along a rostro-caudal axis from the most complex high-order association areas to the simplest idiotopic areas. The rostro-caudal axis along which the 12 regions were organized also reflected a gradient of cortical thickness, myelination, and cell body density. Importantly, across the identified regions, this gradient of microstructural features was strongly associated with the varying degree of information processing complexity. These new anatomical signatures shed light onto the structural organization of the frontal lobes and could help strengthen the prediction or diagnosis of neurodevelopmental and neurodegenerative disorders.
      PubDate: 2016-07-26
       
  • Network Structure among Brain Systems in Adult ADHD is Uniquely Modified
           by Stimulant Administration
    • Authors: Cary RP; Ray S, Grayson DS, et al.
      Abstract: AbstractCurrent research in connectomics highlights that self-organized functional networks or “communities” of cortical areas can be detected in the adult brain. This perspective may provide clues to mechanisms of treatment response in psychiatric conditions. Here we examine functional brain community topology based on resting-state fMRI in adult Attention-Deficit/Hyperactivity Disorder (ADHD; n = 22) and controls (n = 31). We sought to evaluate ADHD patterns in adulthood and their modification by short term stimulants administration. Participants with ADHD were scanned one or two weeks apart, once with medication and once without; comparison participants were scanned at one time-point. Functional connectivity was estimated from these scans and community detection applied to determine cortical network topology. Measures of change in connectivity profile were calculated via a graph measure, termed the Node Dissociation Index (NDI). Compared to controls, several cortical networks had atypical connectivity in adults with ADHD when withholding stimulants, as measured by NDI. In most networks stimulants significantly reduced, but did not eliminate, differences in the distribution of connections between key brain systems relative to the control sample. These findings provide an enriched model of connectivity in ADHD and demonstrate how stimulants may exert functional effects by altering connectivity profiles in the brain.
      PubDate: 2016-07-14
       
  • Differential Regulation of Human Paired Associative Stimulation-Induced
           and Theta-Burst Stimulation-Induced Plasticity by L-type and T-type Ca 2+
           Channels
    • Authors: Weise D; Mann J, Rumpf J, et al.
      Abstract: AbstractActivity-dependent changes of postsynaptic Ca2+-concentration are influenced by a variety of different Ca2+-channels and play an important role in synaptic plasticity. Paired associative stimulation (PAS) and theta-burst stimulation (TBS) are noninvasive magnetic stimulation protocols used in human subjects to induce lasting corticospinal excitability changes that have been likened to synaptic long-term potentiation and long-term depression. To better characterize the Ca2+-related physiological mechanisms underlying PAS- and TBS-induced plasticity, we examined the impact of different Ca2+-sources. PAS-induced facilitation of corticospinal excitability was blocked by NMDA-receptor blocker dextromethorphan (DXM) and L-type voltage gated Ca2+ channels (VGCC) blocker nimodipine (NDP), but turned into depression by T-type VGCC blocker ethosuximide (ESM). Although, surprisingly, static corticospinal excitability was increased by the combination of DXM and NDP, PAS-induced facilitation was blocked. TBS-induced facilitation of corticospinal excitability, which has previously been shown to be turned into depression by L-type VGCC blocker NDP (Wankerl K, Weise D, Gentner R, Rumpf J, Classen J. 2010. L-type voltage-gated Ca2+ channels: a single molecular switch for long-term potentiation/long-term depression-like plasticity and activity-dependent metaplasticity in humans. J Neurosci. 30(18):6197–6204.), was blocked, but not reverted, by T-type VGCC blocker ESM. The different patterns of Ca2+-channel modulation of PAS- and TBS-induced plasticity may point to an important role of backpropagating action potentials in PAS-induced plasticity, similar as in spike-timing dependent synaptic plasticity, and to a requirement of dendritic Ca2+-dependent spikes in TBS-induced plasticity.
      PubDate: 2016-07-11
       
  • Frontoparietal Functional Connectivity in the Common Marmoset
    • Authors: Ghahremani M; Hutchison R, Menon RS, et al.
      Abstract: AbstractIn contrast to the well established macaque monkey, little is known about functional connectivity patterns of common marmoset monkey (Callithrix jacchus) that is poised to become the leading transgenic primate model. Here, we used resting-state ultra-high-field fMRI data collected from anesthetized marmosets and macaques along with awake human subjects, to examine and compare the brain's functional organization, with emphasis on the saccade system. Exploratory independent component analysis revealed eight resting-state networks in marmosets that greatly overlapped with corresponding macaque and human networks including a distributed frontoparietal network. Seed-region analyses of the superior colliculus (SC) showed homolog areas in macaques and marmosets. The marmoset SC displayed the strongest frontal functional connectivity with area 8aD at the border to area 6DR. Functional connectivity of this frontal region revealed a similar functional connectivity pattern as the frontal eye fields in macaques and humans. Furthermore, areas 8aD, 8aV, PG,TPO, TE2, and TE3 were identified as major hubs based on region-wise evaluation of betweeness centrality, suggesting that these cortical regions make up the functional core of the marmoset brain. The results support an evolutionarily preserved frontoparietal system and provide a starting point for invasive neurophysiological studies in the marmoset saccade and visual systems.
      PubDate: 2016-07-08
       
  • Inhibition of Information Flow to the Default Mode Network During
           Self-Reference Versus Reference to Others
    • Authors: Soch J; Deserno L, Assmann A, et al.
      Abstract: AbstractThe default mode network (DMN), a network centered around the cortical midline, shows deactivation during most cognitive tasks and pronounced resting-state connectivity, but is actively engaged in self-reference and social cognition. It is, however, yet unclear how information reaches the DMN during social cognitive processing. Here, we addressed this question using dynamic causal modeling (DCM) of functional magnetic resonance imaging (fMRI) data acquired during self-reference (SR) and reference to others (OR). Both conditions engaged the left inferior frontal gyrus (LIFG), most likely reflecting semantic processing. Within the DMN, self-reference preferentially elicited rostral anterior cingulate and ventromedial prefrontal cortex (rACC/vmPFC) activity, whereas OR engaged posterior cingulate and precuneus (PCC/PreCun). DCM revealed that the regulation of information flow to the DMN was primarily inhibitory. Most prominently, SR elicited inhibited information flow from the LIFG to the PCC/PreCun, while OR was associated with suppression of the connectivity from the LIFG to the rACC/vmPFC. These results suggest that task-related DMN activation is enabled by inhibitory down-regulation of task-irrelevant information flow when switching from rest to stimulus-specific processing.
      PubDate: 2016-07-08
       
  • Pleiotropic Hes-1 Concomitant with its Differential Activation Mediates
           Neural Stem Cell Maintenance and Radial Glial Propensity in Developing
           Neocortex
    • Authors: Dhanesh S; Subashini C, Riya P, et al.
      Abstract: AbstractNotch signaling pathway and its downstream effector Hes-1 are well known for their role in cortical neurogenesis. Despite the canonical activation of Hes-1 in developing neocortex, recent advances have laid considerable emphasis on Notch/CBF1-independent Hes-1 (NIHes-1) expression with poor understanding of its existence and functional significance. Here, using reporter systems and in utero electroporation, we could qualitatively unravel the existence of NIHes-1 expressing neural stem cells from the cohort of dependent progenitors throughout the mouse neocortical development. Though Hes-1 expression is maintained in neural progenitor territory at all times, a simple shift from Notch-independent to -dependent state makes it pleiotropic as the former maintains the neural stem cells in a non-dividing/slow-dividing state, whereas the latter is very much required for maintenance and proliferation of radial glial cells. Therefore, our results provide an additional complexity in neural progenitor heterogeneity regarding differential Hes-1 expression in the germinal zone during neo-cortical development.
      PubDate: 2016-07-08
       
  • Cognitive Reserve and Brain Maintenance: Orthogonal Concepts in Theory and
           Practice
    • Authors: Habeck CC; Razlighi QQ, Gazes YY, et al.
      Abstract: AbstractCognitive Reserve and Brain Maintenance have traditionally been understood as complementary concepts: Brain Maintenance captures the processes underlying the structural preservation of the brain with age, and might be assessed relative to age-matched peers. Cognitive Reserve, on the other hand, refers to how cognitive processing can be performed regardless of how well brain structure has been maintained. Thus, Brain Maintenance concerns the “hardware,” whereas Cognitive Reserve concerns “software,” that is, brain functioning explained by factors beyond mere brain structure. We used structural brain data from 368 community-dwelling adults, age 20–80, to derive measures of Brain Maintenance and Cognitive Reserve. We found that Brain Maintenance and Cognitive were uncorrelated such that values on one measure did not imply anything about the other measure. Further, both measures were positively correlated with verbal intelligence and education, hinting at formative influences of the latter to both measures. We performed extensive split-half simulations to check our derived measures’ statistical robustness. Our approach enables the out-of-sample quantification of Brain Maintenance and Cognitive Reserve for single subjects on the basis of chronological age, neuropsychological performance and structural brain measures. Future work will investigate the prognostic power of these measures with regard to future cognitive status.
      PubDate: 2016-07-08
       
  • Volume Loss of the Nucleus Basalis of Meynert is Associated with Atrophy
           of Innervated Regions in Mild Cognitive Impairment
    • Authors: Cantero JL; Zaborszky L, Atienza M.
      Abstract: AbstractExtensive research suggests that basal forebrain (BF) cholinergic neurons are selectively vulnerable to Alzheimer's disease (AD). However, it remains unknown whether volume loss of BF cholinergic compartments parallels structural changes of their innervated regions in prodromal AD. To this aim, we have correlated volume of each BF compartment with cortical thickness and hippocampus/amygdala volume in 106 healthy older (HO) adults and 106 amnestic mild cognitive impairment (aMCI) patients. Correlations were limited to regions affected by atrophy in aMCI. The volume of the nucleus basalis of Meynert (NBM/Ch4) was positively correlated with thickness of the temporal cortex in aMCI, and with volume of amygdala in HO and aMCI, separately. Volume of the medial septum/diagonal band of Broca (Ch1–Ch3) was also positively correlated with volume of the hippocampus within the 2 groups. Only correlations between the NBM and their innervated regions showed diagnostic value. Unlike men, aMCI women showed a stronger association between volume of the NBM and thickness of the temporal lobe when compared with HO women. Altogether, these results reveal, for the first time in humans, that atrophy of NBM is associated with structural changes of their innervated regions in prodromal AD, being this relationship more evident in women.
      PubDate: 2016-07-01
       
  • Developmental Alcohol Exposure Impairs Activity-Dependent S- Nitrosylation
           of NDEL1 for Neuronal Maturation
    • Authors: Saito A; Taniguchi Y, Kim S, et al.
      Abstract: AbstractNeuronal nitric oxide synthase is involved in diverse signaling cascades that regulate neuronal development and functions via S-Nitrosylation-mediated mechanism or the soluble guanylate cyclase (sGC)/cyclic guanosine monophosphate (cGMP) pathway activated by nitric oxide. Although it has been studied extensively in vitro and in invertebrate animals, effects on mammalian brain development and underlying mechanisms remain poorly understood. Here we report that genetic deletion of “Nos1” disrupts dendritic development, whereas pharmacological inhibition of the sGC/cGMP pathway does not alter dendritic growth during cerebral cortex development. Instead, nuclear distribution element-like (NDEL1), a protein that regulates dendritic development, is specifically S-nitrosylated at cysteine 203, thereby accelerating dendritic arborization. This post-translational modification is enhanced by N-methyl-D-aspartate receptor-mediated neuronal activity, the main regulator of dendritic formation. Notably, we found that disruption of S-Nitrosylation of NDEL1 mediates impaired dendritic maturation caused by developmental alcohol exposure, a model of developmental brain abnormalities resulting from maternal alcohol use. These results highlight S-Nitrosylation as a key activity-dependent mechanism underlying neonatal brain maturation and suggest that reduction of S-Nitrosylation of NDEL1 acts as a pathological factor mediating neurodevelopmental abnormalities caused by maternal alcohol exposure.
      PubDate: 2016-07-01
       
 
 
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