Document Detail


Differential connectivity of short- vs. long-range extrinsic and intrinsic cortical inputs to perirhinal neurons.
MedLine Citation:
PMID:  23296922     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The perirhinal cortex plays a critical role in recognition and associative memory. However, the network properties that support perirhinal contributions to memory are unclear. To shed light on this question, we compared the synaptic articulation of short- and long-range inputs from the perirhinal cortex or temporal neocortex with perirhinal neurons in rats. Iontophoretic injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHAL) were performed at different rostrocaudal levels of the ventral temporal neocortex or perirhinal cortex, and electron microscopic observations of anterogradely labeled (PHAL(+)) axon terminals found at perirhinal sites adjacent to or rostrocaudally distant from the injection sites were performed. After neocortical injections, the density of PHAL(+) axons in the perirhinal cortex decreased steeply with rostrocaudal distance from the injection sites, much more so than following perirhinal injections. Otherwise, similar results were obtained with neocortical and perirhinal injections. In both cases, most (76-86%) PHAL(+) axon terminals formed asymmetric synapses, typically with spines (type A, 83-89%) and less frequently with dendritic profiles (type B, 11-17%). The remaining terminals formed symmetric synapses with dendritic profiles (type C, 14-23%). Type B and C synapses were 2.4-2.6 times more frequent in short- than long-range connections. The postsynaptic elements in type A-C synapses were identified with immunocytochemistry for CAMKIIα, a marker of glutamatergic cortical neurons. Type A and C terminals contacted CAMKIIα-positive principal cells, whereas type B synapses contacted presumed inhibitory neurons. Overall, these results suggest that principal perirhinal neurons are subjected to significantly more inhibition from short- than from long-range cortical inputs, an organization that likely impacts perirhinal contributions to memory.
Authors:
Gunes Unal; Jean-Francois Pare; Yoland Smith; Denis Pare
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural    
Journal Detail:
Title:  The Journal of comparative neurology     Volume:  521     ISSN:  1096-9861     ISO Abbreviation:  J. Comp. Neurol.     Publication Date:  2013 Aug 
Date Detail:
Created Date:  2013-06-05     Completed Date:  2014-01-13     Revised Date:  2014-08-05    
Medline Journal Info:
Nlm Unique ID:  0406041     Medline TA:  J Comp Neurol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2538-50     Citation Subset:  IM    
Copyright Information:
Copyright © 2013 Wiley Periodicals, Inc.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Axons / physiology
Calcium-Calmodulin-Dependent Protein Kinase Type 2 / metabolism
Cerebral Cortex / cytology,  physiology*
Data Interpretation, Statistical
Immunohistochemistry
Male
Microscopy, Electron
Neural Pathways / cytology,  physiology*
Neurons / physiology*
Phytohemagglutinins
Rats
Rats, Sprague-Dawley
Recruitment, Neurophysiological / physiology
Synapses / physiology
Temporal Lobe / cytology,  physiology
Grant Support
ID/Acronym/Agency:
R01 MH-073610/MH/NIMH NIH HHS; R01 MH073610/MH/NIMH NIH HHS; RR-00165/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Phytohemagglutinins; 0/leukoagglutinins, plants; EC 2.7.11.17/Calcium-Calmodulin-Dependent Protein Kinase Type 2
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Structure-based whole genome realignment reveals many novel non-coding RNAs.
Next Document:  Kinetic Resolution of Tertiary Alcohols: Highly Enantioselective Access to 3-Hydroxy-3-Substituted O...