PT  - JOURNAL ARTICLE
AU  - Tatsuya Umeda
AU  - Tadashi Isa
AU  - Yukio Nishimura
TI  - The primary motor cortex prospectively computes the spinal reflex
AID  - 10.1101/2020.06.29.170928
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.06.29.170928
4099  - http://biorxiv.org/content/early/2020/06/29/2020.06.29.170928.short
4100  - http://biorxiv.org/content/early/2020/06/29/2020.06.29.170928.full
AB  - The spinal reflex transforms sensory signals to generate muscle activity. However, it is unknown how the motor cortex (MCx) takes the spinal reflex into account when performing voluntary limb movements. We simultaneously recorded the activity of the MCx, afferent neurons, and forelimb muscles in behaving monkeys. We decomposed muscle activity into subcomponents explained by the MCx or afferent activity using linear models. Long preceding activity in the MCx, which is responsible for subsequent afferent activity, had the same spatiotemporal contribution to muscle activity as afferent activity, indicating that the MCx drives muscle activity not only by direct descending activation but also by trans-afferent descending activation. Therefore, the MCx implements internal models that prospectively estimate muscle activation via the spinal reflex for precise movement control.Competing Interest StatementThe authors have declared no competing interest.