Friday Lunch Seminar (English)

December 24, 2021
12:15 〜 13:00
(On-line)
Apply for participation from here by noon, December 23.
You will be notified of participation details by e-mail on December 23.

Talk Title: Contribution of NREM and REM sleep to visual perceptual learning

Masako Tamaki
Team leader
Center for Brain Science, RIKEN

Host: Okito Yamashita

Abstract:
The role of sleep in facilitating learning has remained unclear. In visual perceptual learning (VPL), on the one hand, it has been demonstrated that NREM sleep plays a role in improvements beyond posttraining performance (offline performance gains), while REM sleep makes learning more resilient to interference (stabilization). These suggest that plasticity of the visual system increases during NREM sleep, while it decreases during REM sleep for VPL facilitation. On the other hand, use-dependent models have assumed that sleep processing leading to performance gains occurs based on general cortical usage during wakefulness, not specific to learning. In the present study, we first tested how the plasticity of the visual system is associated with offline gains and stabilization in VPL during sleep, by using magnetic resonance spectroscopy in asleep human subjects. We measured the concentrations of neurotransmitters in the early visual areas during sleep and obtained the excitation/inhibition (E/I) ratio which represents the amount of plasticity of the visual areas during sleep. We found that the E/I ratio significantly increased during NREM sleep while it decreased during REM sleep. The E/I ratio during NREM sleep was correlated with offline performance gains, while the E/I ratio during REM sleep was correlated with stabilization. Furthermore, we found that sleep processing leading to performance gains is learning-dependent, not use-dependent in VPL and involves occipital sigma during NREM sleep and theta activity during REM sleep. These results show that NREM sleep increases plasticity, while REM sleep decreases it to stabilize once enhanced VPL. NREM and REM sleep may play complementary roles for learning, which are reflected by significantly different neurochemical processing.