Confocal mapping of cortical inputs onto identified pyramidal neurons.
Using a confocal microscopy protocol, we carried out a microcircuitry investigation of cortical connections in monkey temporal cortex. Inputs were labeled by BDA injections in posterior area TE, and potential postsynaptic pyramidal neuron targets were labeled with EGFP, by injection of retrogradely transported adenovirus. We scored the number and distribution of putative contacts onto dendritic compartments of neurons in different layers. Initial results show that about 50 percent of apical dendrites of layer (L.) 6 neurons receive contacts, as they ascend through L.4 (n=1 brain), but only 30-35 percent of those from L.5 neurons (n=2). Basal dendrites of L.3 neurons also receive few contacts in L.4. This supports the role of layer 4 as an interlaminar relay in association cortex. In addition, our results indicate spatial heterogeneity in the occurrence and number of contacts, possibly due to subtype specificity in target preference. The maximum number of contacts, for a L.2 neuron projecting from anterior to posterior TE, was 29. This approach seems a useful alternative or complement to electron microscopic analyses of long distance connectivity.
Lab for Cortical Organization and Systematics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan.
Noritaka
N
Ichinohe
James
J
Hyde
Atsuko
A
Matsushita
Kazumi
K
Ohta
Kathleen S
KS
Rockland
D000818:Animals; D001921:Brain / Q000502:physiology; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D008253:Macaca mulatta; D008564:Membrane Potentials / Q000502:physiology; D018613:Microscopy, Confocal / Q000379:methods*; D009474:Neurons / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D017966:Pyramidal Cells / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology
C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins