SPINOCEREBELLAR PURKINJE-CELLS AND RAT FORELIMB POSTURES - A DIRECTION-DEPENDENT ACTIVITY

On anesthetized adult rats, we examined the possibility that the disch arges of spinocerebellar Purkinje cells (PCs) are modulated by passive limb positioning. The rat forelimb was passively placed in four diffe rent sagittal positions while the simple spike spontaneous activity of single PCs was recorded; recordings started 5 s after the reaching of the posture and the forelimb remained at each position for at least 3 0 s. Although the activity of the PCs did not reflect the forelimb pos ition, it showed hysteresis that depended in a cosine fashion on the d irection of the preceding movement. This implies that the directional sensitivity of spinocerebellar PCs is persistent, since the activity l evels were almost constant throughout the recording time. (C) 1998 Els evier Science Ireland Ltd.