A parallel neural circuit model for bimodal distribution of reaction time in a predictive saccade task

In predictive saccade tasks within precise time intervals, the reaction time of macaque exhibits a bimodal distribution． To investigate this phenomenon further, a parallel neural circuit model that includes the lateral intraparietal area (LIP), supplementary eye fields (SEF) in the cerebral cortex, the basal ganglia (BG) and superior colliculus (SC) is proposed in this study． Model simulations successfully reproduced a bimodal distribution． Competitive interaction among neuronal populations in SEF and LIP regions was found to give rise to two peaks． SEF region primarily was found to handle predictive saccades and dominated the first peak, while LIP region was found to be responsible for visually evoked reactive saccades and dominated the second peak． Key parameters that influence morphology of bimodal distribution are discussed． The process of time expectation from the perspective of computational neuroscience is explored．