To elucidate how the flattening of sensory tuning due to a deficit in tonic inhibition slows motor responses, we simulated a neural network model in which a sensory cortical network (NS) and a motor cortical network (NM) are reciprocally connected, and the NM projects to spinal motoneurons (Mns). The NS was presented with a feature stimulus and the reaction time of Mns was measured. The flattening of sensory tuning in NS caused by decreasing the centration of GABA in extracellular space resulted in a decrease in the stimulus-sensitive NM pyramidal cell activity while increasing the stimulus-insensitive NM pyramidal cell activity, thereby prolonging the reaction time of Mns to the applied feature stimulus. We suggest that a reduction in extracellular GABA concentration in sensory cortex may interfere with selective activation in motor cortex, leading to slowing the activation of spinal motoneurons and therefore to slowing motor responses.
Model Type: Spiking neural network
Region(s) or Organism(s): Neocortex; Spinal motoneuron
Cell Type(s): Abstract integrate-and-fire leaky neuron
Model Concept(s): Action Potentials
Simulation Environment: C or C++ program
Hoshino O, Zheng M, Fukuoka Y. (2022). Effect of cortical extracellular GABA on motor response Journal of computational neuroscience 50 [PubMed]