Serotonin affects movement gain control in the spinal cord

Kunlin Wei*, Joshua I. Glaser, Linna Deng, Christopher K. Thompson, Ian H. Stevenson, Qining Wang, Thomas George Hornby, Charles J. Heckman, Konrad P. Kording

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations


A fundamental challenge for the nervous system is to encode signals spanning many orders of magnitude with neurons of limited bandwidth. To meet this challenge, perceptual systems use gain control. However, whether the motor system uses an analogous mechanism is essentially unknown. Neuromodulators, such as serotonin, are prime candidates for gain control signals during force production. Serotonergic neurons project diffusely to motor pools, and, therefore, force production by one muscle should change the gain of others. Here we present behavioral and pharmaceutical evidence that serotonin modulates the inputoutput gain of motoneurons in humans. By selectively changing the efficacy of serotonin with drugs, we systematically modulated the amplitude of spinal reflexes. More importantly, force production in different limbs interacts systematically, as predicted by a spinal gain control mechanism. Psychophysics and pharmacology suggest that the motor system adopts gain control mechanisms, and serotonin is a primary driver for their implementation in force production.

Original languageEnglish (US)
Pages (from-to)12690-12700
Number of pages11
JournalJournal of Neuroscience
Issue number38
StatePublished - Sep 17 2014


  • Efficient control
  • Gain control
  • Neuromodulation
  • Pharmacology
  • Serotonin
  • Spinal cord

ASJC Scopus subject areas

  • Neuroscience(all)

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