Conflict Resolution as Near-Threshold Decision-Making: A Spiking Neural Circuit Model with Two-Stage Competition for Antisaccadic Task
Fig 2
The detailed model circuits for antisaccade task.
A. The action-selection module. The two excitatory populations of saccade neurons (SacL & SacR) receive sensory input and modulation from the remapping module. The two populations compete with each other through the inhibitory interneuron population (I0) and also form mutual inhibitions with the fixation neuron populations FNL or FNR through inhibitory interneuron populations I1-I4. FNL and FNR are driven by the fixation signal and the top-down gaze-holding control which depends on the rule signal. B. The remapping module. The visual layer in the remapping module consists of neural populations that represent all possible sensorimotor maps including the direct map (the strongest by default) and the inverted map, which can be facilitated after training. The signals from the direct and inverted maps compete with each other in the decision layer and the outcome drives the downstream action-selection module. C. Schematics of anti- and prosaccade responses. In a prosaccade trial, the left visual signal directly triggers a left saccade by activating SacL. The signal from the direct map in the remapping module may also contribute to the generation of saccades. During an antisaccade, the saccade neurons in SacL and SacR are temporally suppressed by the top-down gaze-holding control. In the mean time the top-down control facilitates the visual response of the inverted map, which strongly activates the decision population DecR. As a result, DecR wins the competition and activates SacR. Note that we neglect the decussation of the nervous systems in order to avoid complexity in the graphical representation.