Neural Correlates of Sleep, and Game-Playing in Bonnet Macaques

Abstract

In visual neuroscience, the traditional system of recording neural activity (a highly constrained and artificial environment) often falls short due to its limited capacity to capture natural behaviours. One of these natural behaviours (and an extremely prominent one) is sleep. Sleep is an essential behavioural state that is known to be crucial for the proper functioning of the brain and the body. Despite its importance, the neural correlates of sleep are not well understood, especially in nonhuman primates. In this thesis, we investigate the neural correlates of sleep in bonnet macaques, a species of nonhuman primates. We recorded neural activity from the inferotemporal (IT) region, the ventro-lateral prefrontal cortex (vlPFC), and the ventral premotor area (PMv) of the brain, while the monkeys slept naturally. We find that the firing rates of the neurons in the PMv region are significantly lower during sleep compared to wakefulness, while the firing rates in the IT region have a marked increase in their variance. We also find that the power in the delta band of the local field potentials (LFPs) is significantly higher during sleep compared to wakefulness, in all the regions. These results suggest that there are clear neural correlates of sleep that can be distinguished from those during wakefulness, and that these have similarities to those observed in humans and rhesus macaques. In the second part of the thesis, we present our training of the macaques towards a new task paradigm - that of using four direction buttons on the touchscreen to move a character around the screen, with the goal of obtaining “reward” objects. Overall, this thesis provides new insights into the neural correlates of sleep in bonnet macaques as well as showcases a paradigm for the training for playing games, and highlights the importance of studying natural behaviours in nonhuman primates.