TY - JOUR
T1 - Efficacy of thalamocortical and intracortical synaptic connections
T2 - Quanta, innervation, and reliability
AU - Ziv, Gil
AU - Connors, Barry W.
AU - Amitai, Yael
N1 - Funding Information:
We thank Michael Beierlein, Gerald Finnerty, Jay Gibson, Carole Landisman, David Pinto, and Clay Reid for comments on the manuscript. This work was supported by a grant from the Israel Science Foundation (Y. A.), a Fogarty International Collaboration Research Award (TW00743 from NIH) (Y. A. and B. W. C.), and grant NS25983 (NIH) (B. W. C.). Z. G. is a Fellow of the Kreitman School of Advanced Studies.
PY - 1999/1/1
Y1 - 1999/1/1
N2 - Thalamocortical (TC) synapses carry information into the neocortex, but they are far outnumbered by excitatory intracortical (IC) synapses. We measured the synaptic properties that determine the efficacy of TC and IC axons converging onto spiny neurons of layer 4 in the mouse somatosensory cortex. Quantal events from TC and IC synapses were indistinguishable. However, TC axons had, on average, about 3 times more release sites than IC axons, and the mean release probability at TC synapses was about 1.5 times higher than that at IC synapses. Differences of innervation ratio and release probability make the average TC connection several times more effective than the average IC connection, and may allow small numbers of TC axons to dominate the activity of cortical layer 4 cells during sensory inflow.
AB - Thalamocortical (TC) synapses carry information into the neocortex, but they are far outnumbered by excitatory intracortical (IC) synapses. We measured the synaptic properties that determine the efficacy of TC and IC axons converging onto spiny neurons of layer 4 in the mouse somatosensory cortex. Quantal events from TC and IC synapses were indistinguishable. However, TC axons had, on average, about 3 times more release sites than IC axons, and the mean release probability at TC synapses was about 1.5 times higher than that at IC synapses. Differences of innervation ratio and release probability make the average TC connection several times more effective than the average IC connection, and may allow small numbers of TC axons to dominate the activity of cortical layer 4 cells during sensory inflow.
UR - http://www.scopus.com/inward/record.url?scp=0033151713&partnerID=8YFLogxK
U2 - 10.1016/S0896-6273(00)80788-6
DO - 10.1016/S0896-6273(00)80788-6
M3 - Article
AN - SCOPUS:0033151713
SN - 0896-6273
VL - 23
SP - 385
EP - 397
JO - Neuron
JF - Neuron
IS - 2
ER -