TY - JOUR
T1 - The Emergence of Contrast-Invariant Orientation Tuning in Simple Cells of Cat Visual Cortex
AU - Finn, Ian M.
AU - Priebe, Nicholas J.
AU - Ferster, David
N1 - Funding Information:
We thank Kenneth. D. Miller for helpful discussions and Matteo Carandini, Stephen G. Lisberger, Larry Abbott, and Wilson S. Geisler for comments on the manuscript. Supported by grants from the National Eye Institute (R01 EY04726) and National Institute of Mental Health (P20 MH066239).
PY - 2007/4/5
Y1 - 2007/4/5
N2 - Simple cells in primary visual cortex exhibit contrast-invariant orientation tuning, in seeming contradiction to feed-forward models that rely on lateral geniculate nucleus (LGN) input alone. Contrast invariance has therefore been thought to depend on the presence of intracortical lateral inhibition. In vivo intracellular recordings instead suggest that contrast invariance can be explained by three properties of the excitatory pathway. (1) Depolarizations evoked by orthogonal stimuli are determined by the amount of excitation a cell receives from the LGN, relative to the excitation it receives from other cortical cells. (2) Depolarizations evoked by preferred stimuli saturate at lower contrasts than the spike output of LGN relay cells. (3) Visual stimuli evoke contrast-dependent changes in trial-to-trial variability, which lead to contrast-dependent changes in the relationship between membrane potential and spike rate. Thus, high-contrast, orthogonally oriented stimuli that evoke significant depolarizations evoke few spikes. Together these mechanisms, without lateral inhibition, can account for contrast-invariant stimulus selectivity.
AB - Simple cells in primary visual cortex exhibit contrast-invariant orientation tuning, in seeming contradiction to feed-forward models that rely on lateral geniculate nucleus (LGN) input alone. Contrast invariance has therefore been thought to depend on the presence of intracortical lateral inhibition. In vivo intracellular recordings instead suggest that contrast invariance can be explained by three properties of the excitatory pathway. (1) Depolarizations evoked by orthogonal stimuli are determined by the amount of excitation a cell receives from the LGN, relative to the excitation it receives from other cortical cells. (2) Depolarizations evoked by preferred stimuli saturate at lower contrasts than the spike output of LGN relay cells. (3) Visual stimuli evoke contrast-dependent changes in trial-to-trial variability, which lead to contrast-dependent changes in the relationship between membrane potential and spike rate. Thus, high-contrast, orthogonally oriented stimuli that evoke significant depolarizations evoke few spikes. Together these mechanisms, without lateral inhibition, can account for contrast-invariant stimulus selectivity.
KW - SYSNEURO
UR - http://www.scopus.com/inward/record.url?scp=33947631976&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33947631976&partnerID=8YFLogxK
U2 - 10.1016/j.neuron.2007.02.029
DO - 10.1016/j.neuron.2007.02.029
M3 - Article
C2 - 17408583
AN - SCOPUS:33947631976
SN - 0896-6273
VL - 54
SP - 137
EP - 152
JO - Neuron
JF - Neuron
IS - 1
ER -