CBBM Lecture - Sleep: sensory disconnection and memory consolidation

by Yuval Nir, Sagol School of Neuroscience, Department of Physiology and Pharmacology, Tel Aviv University, Israel

Yuval Nir

will take place on Tuesday, February 8th, 2022, Time: 3 pm German time (15:00 hours)

Host: Jonas Obleser
Department of Psychology

Abstract: A fundamental feature of sleep is that a sensory stimulus does not reliably affect behavior or subjective experience. What mediates such “sensory disconnection”? Do similar processes occur during anesthesia, cognitive lapses, and some neuropsychiatric disorders?  In a series of studies in humans and rodents, we compared neuronal responses to identical auditory stimuli across wakefulness and sleep. In A1, early single-neuron spiking responses are largely comparable across wakefulness, natural sleep, and light anesthesia. However, robust differences emerge in downstream high-level regions and late-responding neurons, and in signatures of feedback processing, suggesting that sleep impairs effective cortical connectivity. Next, we show that reduced locus coeruleus-noradrenaline (LC-NE) activity during sleep mediates sensory disconnection. In rodents, the level of ongoing tonic LC activity during sleep anticipates sound-evoked awakenings, while minimal optogenetic LC activation or silencing increases and decreases such awakenings, respectively. In humans, pharmacological manipulation of NE levels modulates sensory perception and late sensory responses, suggesting that NE links sensory awareness to external world events. We are exploring novel methods such as transcutaneous vagal nerve stimulation to modulate LC-NE non-invasively in humans.  Finally, I will present recent results on sleep and memory consolidation. In epilepsy patients implanted with depth electrodes we investigate the effects of intracranial electrical closed loop stimulation during sleep on memory and hippocampal-neocortical dialogue at single-neuron resolution.

Biosketch: Prof. Nir is an investigator at Tel Aviv University (Israel). Prof. Nir studied Computer Science and Neuroscience at Tel Aviv University, proceeded to a PhD in neurobiology  at the Weizmann Institute (with Rafi Malach), and then to a postdoctoral fellowship focusing on sleep with Chiara Cirelli and Giulio Tononi at UW-Madison. In 2012, Prof. Nir set up his own lab at Tel Aviv: http://yuvalnirlab.com. Research in the lab focuses on sleep and its relation to cognition by combining rodent and human research.