Forgetting hippocampus-dependent memories by hypothalamic MCH neurons during REM sleep

Shuntaro Izawa

Max Planck Institute for Metabolism Research

The neural mechanisms underlying memory regulation during sleep are not yet fully understood.　We found that melanin-concentrating hormone-producing neurons （MCH neurons） in the hypothalamus contribute to forgetting during rapid eye movement （REM） sleep.　Hypothalamic MCH neurons densely innervated the dorsal hippocampus, and activation or inhibition of MCH neurons impaired or improved hippocampus-dependent memory, respectively.　REM sleep state-dependent inhibition of MCH neurons improved hippocampus-dependent memory without affecting sleep architecture or quality.　REM sleep active MCH neurons in the hypothalamus are thus involved in forgetting in the hippocampus.　In addition to our findings in mice, recent studies in humans also suggest that MCH neurons innervate and regulate hippocampal neurons and functions.

Address correspondence to Dr. Shuntaro Izawa, Max Planck Institute for Metabolism Research（Gleueler Str. 50, 50931, Cologne, Germany）