Global dissociation of the amygdala from the rest of the brain during REM sleep

Abstract

Rapid-eye-movement sleep (REMS) or paradoxical sleep is associated with intense neuronal activity, fluctuations in autonomic control, body paralysis and brain-wide hyperemia. The mechanisms and functions of these energy-demanding patterns remain elusive and a global picture of brain activation during REMS is currently missing. In the present work, we performed functional ultrasound (fUS) imaging at the whole-brain scale during hundreds of REMS episodes to provide the spatiotemporal dynamics of vascular activity in 259 brain regions spanning more than 2/3 of the total brain volume. We first demonstrate a dissociation between basal/midbrain and cortical structures, the first ones sustaining tonic activation during REMS while the others are activated in phasic bouts. Second, we isolated the vascular compartment in our recordings and identified arteries in the anterior part of the brain as strongly involved in the blood supply during REMS episodes. Finally, we report a peculiar activation pattern in the amygdala, which is strikingly disconnected from the rest of the brain during most but not all REMS episodes. This last finding shows that amygdala undergoes specific processing during REMS and may be linked to the regulation of emotions and the creation of dream content during this very state.

Decoding behavior from global cerebrovascular activity using neural networks

“…For REMS, these were the superior colliculus, which has been shown to play a role in wakefulness induction and is known to be involved in the visual processing of dream content 26 , the striatum and medial septum. These regions, as well as the retrosplenial cortex and the azygos anterior cerebral artery (azac), were also clearly highlighted for REMS on pixel-based maps, which are strongly activated during REMS 27 . For AW, regions clearly highlighted by both ROI-based and pixel-wise analysis were the Dentate Gyrus, which was found to be heavily involved in voluntary running 28 , and to a lesser extent the Limbic Cortex, Subiculum and residual Hippocampus and the Visual and Motor Cortex.…”