During long-duration space flights outside the Earth’s magnetosphere, exposure to galactic cosmic rays and solar energetic particles may lead to early damage to human central nervous system, causing operator activity impairments in astronauts. A conditioned instrumental performance involving saccadic eye movements and manual reactions was studied in two nonhuman primates (Macaca mulatta). One monkey was exposed to a single cranial proton irradiation (170 MeV, 3 Gy). For the other control animal irradiation was simulated. Proton irradiation had no negative effects on instrumental performance during three months after irradiation. However, irradiated monkey showed an increase in saccadic and manual response latencies started at the one month after irradiation and observed next two months. No such effects were found in control monkey. Thus system processes, crucial for conditioned instrumental behaviour, turned out to be widely resistant to proton irradiation, although increase in saccadic and manual response latencies suggests its early negative effects on integrative and executive brain mechanisms.

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L.V. Tereshchenko, I.D. Shamsiev, I.V. Bondar, E.A. Krasavin, A.V. Latanov, "Disturbances in visuomotor behaviour of nonhuman primates after cranial irradiation with high-energy protons," RAD Conf. Proc, vol. 4, 2020, pp. 121–125, http://doi.org/10.21175/RadProc.2020.26