Neuroscience 2007, the 37th annual meeting of the Society for Neuroscience  2007.11.3-7

Program#/Poster#: 279.13/FF1

Title: Difference in electrophysiological properties of layer III pyramidal neurons between cortical areas V1 and TE of the macaque

Location: San Diego Convention Center: Halls B-H
Presentation Start/End Time: Sunday, Nov 04, 2007, 1:00 PM - 2:00 PM

Authors: A. ISHIKAWA1, A. MARUYAMA4, D. HOSOYAMA1, Y. YOSHIMURA5, H. TAMURA2,4, *H. SATO3, I. FUJITA2,4;
1Grad. Sch. Frontier Biosci., Osaka Univ., Osaka 560-0043, Japan; 2Grad. Sch. Frontier Biosci., Osaka Univ., Osaka 560-8531, Japan; 3Grad Sch. Med., Osaka Univ., Osaka 560-0043, Japan; 4CREST, JST, Toyonaka, Japan; 5Res. Ins.Environmental and Med., Nagoya, Japan

The primary visual cortex (V1) and the inferior temporal cortex (area TE) represent early and later stages of the ventral visual cortical pathway, respectively, in macaque monkeys. Neurons in the two areas differ in their dendritic and axonal morphology as well as various aspects of visual responses. It is not known whether neurons in the two areas differ in their biophysical membrane properties. Using brain slice preparation taken from adult Japanese monkeys (Macaca fuscata), we recorded from pyramidal neurons in layer 3 of V1 and TE by whole-cell patch-clamp techniques. Neurons in the two areas exhibited marked differences in a number of characteristics; (1) the membrane time constant was smaller in V1 than in TE, (2) the input resistance was higher in V1 than in TE, (3) inward rectification of responses to hyperpolarizing current injection (“depolarizing sag”) was larger in V1 than in TE, (4) the rate of spike firing evoked by a depolarizing current injection (500 ms) was more rapidly and strongly attenuated in V1 than in TE, (5) the maximum rate of spike firing induced by depolarizing current injection was higher in V1 than in TE, and (6) the width of individual action potentials was shorter in V1 than in TE. These differences point to greater sensitivity of V1 neurons to a temporal change in synaptic inputs as compared to TE neurons. The results suggest that electrophysiological properties of V1 neurons are suitable for processing time-varying stimuli with higher resolution. TE neurons may be more suited for integrating information over a longer time range.