Modeling the Effects of Dopamine on the Antisaccade Reaction Times (aSRT) of Schizophrenia Patients

In the antisaccade task, subjects are instructed to look in the opposite direction of a visually presented stimulus. Controls can perform this task successfully with very few errors, whereas schizophrenia patients make more errors and their responses are slower and more variable. It has been proposed the fundamental cognitive dysfunction in schizophrenia involves prefrontal dopaminergic hypoactivity. We examine via computer simulations the effects of dopamine on the variability of aSRTs in a neural cortico-collicular accumulator model with stochastic climbing activity.We report the simulated aSRTs for the hypo-DA level havehigher standard deviation andmean values than in the normal and hyper DA level. The simulated higher mean and standard deviation for the hypo-DA group resemble the performance differences in the antisaccade task observed in patients with schizophrenia and are in accordance with the theory of a hypo-DA state in the frontal cortical areas of patients with schizophrenia.