Supramammillary regulation of locomotion and hippocampal activity
Jordan S. Farrell, Matthew Lovett-Barron, Peter Klein, Fraser T. Sparks, Tilo Gschwind, Anna L. Ortiz, Biafra Ahanonu, Susanna Bradbury, Satoshi Terada, Mikko Oijala, Ernie Hwaun, Barna Dudok, Gergely Szabó, Mark J. Schnitzer, Karl Deisseroth, Attila Losonczy, Iván Soltész
Abstract
Locomotion-related signals in the brain To calculate where we are in space, continuous knowledge of one’ s speed is necessary. How does the brain know how fast the body is traveling during locomotion? Using in vivo calcium imaging, electrophysiology, optogenetics, cell tracing, and histology, Farrell et al . identified neurons in the rodent supramammillary nucleus of the hypothalamus that encode future locomotor speed and potently drive locomotion when stimulated. Because these locomotor neurons have extensive axons in brain areas that support spatial navigation, this cell type distributes this information selectively to areas that require knowledge of speed. This nucleus is functionally positioned between input from a higher-order cognitive center and the downstream midbrain where locomotor nuclei reside. —PRS