Heterogenous electrophysiological responses of functionally distinct striatal subregions to circadian and sleep-related homeostatic processes.

Abstract

Basal ganglia (BG) are a set of subcortical nuclei that are involved in the control of a wide variety of motor, cognitive, and affective behaviors. Although many behavioral abnormalities associated with BG dysfunction overlap with the clinical picture precipitated by the lack of sleep, the impact of sleep alterations on neuronal activity in BG is unknown. Using wild-type C57BI mice, we investigated the circadian and sleep-related homeostatic modulation of neuronal activity in the three functional subdivisions of the striatum (i.e. sensorimotor, associative, and limbic striatum). We found no circadian modulation of activity in both ventral and dorsomedial striatum while the dorsolateral striatum displayed a significant circadian rhythm with increased firing rates during the subjective dark, active phase. By combining neuronal activity recordings with electroencephalogram (EEG) recordings, we found a strong modulation of neuronal activity by the nature of vigilance states with increased activity during wakefulness and rapid eye movement sleep relative to nonrapid eye movement sleep in all striatal subregions. Depriving animals of sleep for 6 h induced significant, but heterogenous alterations in the neuronal activity across striatal subregions. Notably, these alterations lasted for up to 48 h in the sensorimotor striatum and persisted even after the normalization of cortical EEG power densities. Our results show that vigilance and sleep states as well as their disturbances significantly affect neuronal activity within the striatum. We propose that these changes in neuronal activity underlie both the well-established links between sleep alterations and several disorders involving BG dysfunction as well as the maladaptive changes in behavior induced in healthy participants following sleep loss.