GABAAInhibition Controls Response Gain in Visual Cortex
Open Access
- 20 April 2011
- journal article
- Published by Society for Neuroscience in Journal of Neuroscience
- Vol. 31 (16), 5931-5941
- https://doi.org/10.1523/jneurosci.5753-10.2011
Abstract
GABAAinhibition is thought to play multiple roles in sensory cortex, such as controlling responsiveness and sensitivity, sharpening selectivity, and mediating competitive interactions. To test these proposals, we recorded in cat primary visual cortex (V1) after local iontophoresis of gabazine, the selective GABAAantagonist. Gabazine increased responsiveness by as much as 300%. It slightly decreased selectivity for stimulus orientation and direction, often by raising responses to all orientations. Strikingly, gabazine affected neither contrast sensitivity nor cross-orientation suppression, the competition seen when stimuli of different orientation are superimposed. These results were captured by a simple model in which GABAAinhibition has the same selectivity as excitation and keeps responses to unwanted stimuli below threshold. We conclude that GABAAinhibition in V1 helps enhance stimulus selectivity but is not responsible for competition among superimposed stimuli. It controls the sensitivity of V1 neurons by adjusting their response gain, without affecting their input gain.Keywords
This publication has 64 references indexed in Scilit:
- The Effect of Attention on Neuronal Responses to High and Low Contrast StimuliJournal of Neurophysiology, 2010
- Lateral competition for cortical space by layer-specific horizontal circuitsNature, 2010
- Synaptic and Network Mechanisms of Sparse and Reliable Visual Cortical Activity during Nonclassical Receptive Field StimulationNeuron, 2010
- Representation of Concurrent Stimuli by Population Activity in Visual CortexNeuron, 2009
- Odor Representations in Olfactory Cortex: “Sparse” Coding, Global Inhibition, and OscillationsNeuron, 2009
- Inhibitory Stabilization of the Cortical Network Underlies Visual Surround SuppressionNeuron, 2009
- Petilla terminology: nomenclature of features of GABAergic interneurons of the cerebral cortexNature Reviews Neuroscience, 2008
- Instantaneous correlation of excitation and inhibition during ongoing and sensory-evoked activitiesNature Neuroscience, 2008
- The Emergence of Contrast-Invariant Orientation Tuning in Simple Cells of Cat Visual CortexNeuron, 2007
- Amplification of Trial-to-Trial Response Variability by Neurons in Visual CortexPLoS Biology, 2004