Behavioral relations of medullary reticular formation cells.

The movement correlates of unit activity in medullary reticular formation cells were observed in unrestrained cats. Fifty-four percent of these cells had “laterally asymmetrical” movement relations and 38% had “laterally symmetrical” movement relations. All cells that discharged in relation to active lateral movement of the spinal column discharged preferentially in relation to ipsilateral movements, while all cells responding to passive lateral movement discharged preferentially in relation to contralateral movement. Cells related to movements of the vertebral column in the vertical plane and a small number of units related to facial, laryngeal, paw, and other movements were also found. The specific motor relations of reticular formation cells may explain the findings of previous lesion, stimulation, and recording studies.