Histological analysis of the location of effective thalamic stimulation for tremor. Case report

Chronic electrical stimulation of the thalamus is an effective treatment for essential and parkinsonian tremor. Although the preferred surgical target is generally accepted to lie within the ventral intermediate nucleus (Vim), the relationship between the surgically defined target and the true histologically defined target is addressed in only a few reports, due in large measure to the need for advanced cytoarchitectonic techniques to define the borders of the thalamic nuclei. The authors report on a patient who underwent effective thalamic deep brain stimulation (DBS) for tremor. By defining the boundaries of the thalamic nuclei, they were able to relate effective DBS to electrode location within the anterior region of the ventral posterior lateral nucleus--the proprioceptive shell of the sensory nucleus--and the posteroventral region of the ventral lateral nucleus, which are equivalent to the Vim defined by Hassler, et al.