Lack of suppression of the short-latency vestibulocollic reflex during active head movements in cats.
It is a general belief that the vestibulocollic reflex (VCR) is suppressed when subjects make voluntary head movements, although clear evidence is still lacking. Experiments were performed to examine whether the short-latency VCR evoked by electrical stimulation of the labyrinth is suppressed during active head turns in alert cats that were trained to make rapid horizontal head turns between the two milk feeders positioned 30 degrees left and right in front of the cats. They were also trained to hold the head near the midline to wait for milk, and the VCRs recorded from splenius muscles in these behavioral situations were compared. The short-latency VCR remained during active head turns, and its amplitude was not consistently modulated by the direction of head turns, indicating that it was not suppressed by active head turns.
D000818:Animals; D002415:Cats; D004558:Electric Stimulation; D006257:Head; D009068:Movement; D009132:Muscles / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D014722:Vestibule, Labyrinth / Q000502:physiology*