Science Topics – 108

A Neural Circuit Mechanism of Perceptual Memory Consolidation during Sleep
Daisuke Miyamoto (Masanori Murayama)

Learned information is reactivated in the brain during post-learning sleep for memory consolidation. Memory consolidation can be separated into cellular consolidation in local circuitry and systems consolidation among brain regions. However, the systems consolidation mechanism remains unrevealed compared to cellular consolidation. In our previous report (Manita et al., Neuron, 2015), we identified that circuits between the secondary motor cortex (M2) and the primary somatosensory cortex (S1) are involved in tactile perception. Here, we examined the role of information flow between M2 and S1 in tactile memory consolidation in mice. M2 and S1 neurons are activated during tactile learning and reactivated during post-learning NREM sleep. During NREM sleep, slow oscillation flow was observed in M2→S1 direction (Fig. A). Silencing M2→S1 axons during NREM sleep impaired memory reactivation in S1 and memory consolidation. In reverse, synchronous stimulation to M2 and S1, for enhancing communication between M2 and S1, enhanced memory consolidation during NREM sleep (Fig. B). Furthermore, synchronous stimulation to M2 and S1 during sleep deprivation restored memory consolidation impairment caused by sleep deprivation. Because cerebral cortex can be stimulated noninvasively with transcranial magnetic stimulation etc., improving and sophisticating our stimulation protocols for clinical application might be beneficial for the treatment of the patients with memory deficits and sleep disorders.

Miyamoto D, Hirai D, Fung CCA, Inutsuka A, Odagawa M, Suzuki T, Boehringer R, Adaikkan C, Matsubara C, Matsuki N, Fukai T, McHugh TJ, Yamanaka A, Murayama M. Top-down cortical input during NREM sleep consolidates perceptual memory. Science 352: 1315-1318, 2016.

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(A) Slow oscillations (0.5-4 Hz) during NREM sleep flow from the secondary motor cortex (M2) to the primary somatosensory cortex (S1). (B) Synchronous stimulation at 250 ms interval (2 Hz) to M2 and S1.

Laboratory for Behavioral Neurophysiology, Brain Science Institure, RIKEN, Saitama, Japan