Different effect of chronic electrical stimulation of the region of the superior cerebellar peduncle and the nucleus ventralis intermedius of the thalamus in the treatment of movement disorders.

The stereotactic target for essential tremor is usually restricted to the nucleus ventralis intermedius of the thalamus, where total immediate suppression of tremor is obtained by continuous chronic electrical stimulation. According to authors' experience in cerebral palsy, chronic stimulation of the region of the superior cerebellar peduncle can diminish spasticity and dyskinesias. The effect of this stimulation is gradual and persists, so stimulation is applied 3-8 times daily for 15-20 min, and is accompanied by a feeling of pleasure. After interruption of chronic stimulation, the effects last for days or weeks. It is suggested that the changes in synaptic connections--reactive synaptogenesis--can also contribute.