Timing of knee-related spinal neurons during fictive rostral scratching in the turtle.
Knee-flexor motor activity rhythmically alternated with knee-extensor motor activity during fictive rostral scratching in the spinal turtle. A critical transition from knee-flexor motor activity to knee-extensor motor activity occurred during hip-flexor motor activity. A key feature of this transition was that the end-phases of knee-flexor motor activity were positively correlated with the start-phases of knee-extensor motor activity. We studied spinal interneurons with activities related to this transition. We previously used single-unit recording techniques to characterize a data set of descending propriospinal interneurons during rostral scratching. We focused here on a group of interneurons from this data set with start-phases (on-units) or with end-phases (off-units) near the start of knee-extensor motor activity. We showed that, for a subset of these units, the start-phases of on-units and the end-phases of off-units were positively correlated with the start-phases of knee-extensor motor activity. We present the hypothesis that some of these knee-related on- and off-units may play a role in timing knee motor activity during rostral scratching.
Stein
Paul S G
PS
Department of Biology, Washington University, St. Louis, Missouri 63130, USA. stein@biology.wustl.edu
Daniels-McQueen
Susan
S
D000818:Animals; D004576:Electromyography; D004594:Electrophysiology; D006614:Hindlimb / Q000294:innervation / Q000502:physiology; D007395:Interneurons / Q000502:physiology*; D007596:Joints / Q000294:innervation*; D009068:Movement / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology* / Q000502:physiology*; D014426:Turtles / Q000502:physiology*