Аннотация:During long-term space missions irradiation with Galactic Cosmic Rays may resultin acute damage to human central nervous system (CNS) and, possibly, lead to disturbances ofoperator activity. Three monkeys (Macacamulatta) were trained to perform a visuomotor taskconsisting of saccade and manual responses to visual stimuli, thus constituting a model ofoperator activity. Upon training completion two animals (M1 and M2) were exposed to cranialirradiation with high-energy protons (170 MeV, 3 Gy), while the third (M3) underwentselective irradiation of parietal lobe in Bragg peak (155 MeV, 3 Gy). We noticed no change ininstrumental task performance in course of three months after irradiation (a.i.). Both craniallyirradiated animals demonstrated a highly correlated increase in both saccade and manualresponse latencies one month a.i. M3 experienced earlier and stronger increase in theseparameters starting on the 20th day a.i. Our results suggest that systemic behaviouralmechanisms are resistant to proton irradiation while visual motor integration and executivecontrol systems might be affected, resulting in reaction time increase.