Contrast's effect on spatial summation by macaque V1 neurons.
Stimulation outside the receptive field of a primary visual cortical (V1) neuron reveals intracortical neural interactions. However, previous investigators implicitly or explicitly considered the extent of cortical spatial summation and, therefore, the size of the classical receptive field to be fixed and independent of stimulus characteristics or of surrounding context. On the contrary, we found that the extent of spatial summation in macaque V1 neurons depended on contrast, and was on average 2.3-fold greater at low contrast. This adaptive increase in spatial summation at low contrast was seen in cells throughout V1 and was independent of surround inhibition.
Center for Neural Science, New York University, 4 Washington Pl., New York, New York 10003, USA. sceniak@cns.nyu.edu
M P
MP
Sceniak
D L
DL
Ringach
M J
MJ
Hawken
R
R
Shapley
D000222:Adaptation, Physiological; D000818:Animals; D015350:Contrast Sensitivity; D016014:Linear Models; D008252:Macaca fascicularis; D009474:Neurons / Q000502:physiology; D016011:Normal Distribution; D010775:Photic Stimulation; D013028:Space Perception / Q000502:physiology*; D014793:Visual Cortex / Q000166:cytology / Q000502:physiology*