Perceptual judgments via sensory-motor interaction assisted by cortical GABA

AbstractRecurrent input to sensory cortex, via long-range reciprocal projections between motor and sensory cortices, is essential for accurate perceptual judgments. GABA levels in sensory cortices correlate with perceptual performance. We simulated a neuron-astrocyte network model to investigate how top-down, feedback signaling from a motor network (Nmot) to a sensory network (Nsen) affects perceptual judgments in association with ambient (extracellular) GABA levels. In the Nsen, astrocytic transporters modulated ambient GABA levels around pyramidal cells. A simple perceptual task was implemented: detection of a feature stimulus presented to the Nsen. The Nmot showed distinct perceptual behaviors: hit, fault, and miss. A hit is a correct response to the stimulus, a fault is a wrong response to the stimulus, and a miss is no response to the stimulus. In hits, the feedback signaling increased the gain of Nsen pyramidal cells and accelerated the reaction speed of Nmot pyramidal cells to the stimulus. Without feedback signaling, the Nsen but not Nmot responded to the stimulus, resulting in a miss. With too strong feedback signaling, the Nmot resulted in a fault, namely, stimulus-insensitive but not stimulus-sensitive pyramidal cells wrongly responded. Balancing the feedforward and feedback signaling formed a coherent, ongoing-spontaneous neuronal state, by which the highest hit rate was achieved. A transient reduction in local ambient GABA levels, triggered by the stimulus, contr...
Source: Journal of Computational Neuroscience - Category: Neuroscience Source Type: research