"The sleeping brain: from norepinephrine modulation to memory and neurodegeneration."

Abstract:

Sleep involves disconnection from the external environment, supports memory consolidation, and its disruption is associated with neurodegeneration. In the first part of the talk, I will present a series of studies in humans and rodents where we investigate the role of locus coeruleus norepinephrine (LC-NE) dynamics during sleep in mediating disconnection from the external environment versus awakening by sensory stimuli. We further study how disruptions to such modulation and excessive LC–NE signaling intruding into sleep may represent a common mechanism linking disrupted sleep with stress-related disorders and neurodegeneration through a viscous cycle. Pupillometry during sleep in closed eye conditions is being developed to further explore this in future human studies.  In the second part of the talk, I will share a novel method we developed to study episodic-like memory that is linked with medial temporal lobe activity in humans, without verbal reports. Using the MEGA (Memory Episode Gaze Anticipation) paradigm, anticipatory gaze observed in eye tracking can quantify memory retrieval without verbal report.  In the third and final part of the talk, I will present how sleep can serve as a window into neurodegeneration. Specifically, subclinical interictal epileptiform activity has been suggested to play a role in memory deficits in early Alzheimer's. We developed a method to identify such activity non-invasively, and its occurrence during sleep and anesthesia may mark a fragile cognitive status that is associated with future memory decline. 

Prof. Nir is an investigator at the Tel Aviv University (Israel) and the director of the Sagol Brain Institute at the Tel Aviv Sourasky Medical Center (Ichilov) http://yuvalnirlab.com. Research in the Nir lab focuses on the neuroscience of sleep and cognition by combining rodent and human research.