Year: 2014
Type: article
Abstract: Simple cells in layer 4 of the primary visual cortex of the cat show contrast invariant orientation tuning in which the amplitude of the peak response is proportional to the stimulus but the width of the tuning curve hardly changes with contrast.1 Contrast invariance is thought to be the result from inhibitory inputs and synaptic depression that function to offset excitation for stimuli away from the preferred orientation.Other studies suggest that noise is another contributor to contrast invariance in orientation tuning. 2 The extent to which these 3 mechanisms (inhibition, synaptic depression and noise) individually contribute to contrast invariance is not known.In this study, a computer simulation is used to reconstruct the visual network in the cat except for inhibition and synaptic depression so that the role of noise in contrast invariance can be examined.Noise is mostly due to random synaptic inputs 3 so this study tested the effects of different levels of synaptic noise.The results show that noise has very little effect on contrast-invariance of orientation selectivity.
Author: Ozan Gurcan
Language: English
Subfield: Cognitive Neuroscience
Field: Neuroscience
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W2288879566