The functional neuroanatomy of dystonia

Abstract

Dystonia is a neurological disorder characterized by involuntary twisting movements and postures. There are many different clinical manifestations, and many different causes. The neuroanatomical substrates for dystonia are only partly understood. Although the traditional view localizes dystonia to basal ganglia circuits, there is increasing recognition that this view is inadequate for accommodating a substantial portion of available clinical and experimental evidence. A model in which several brain regions play a role in a network better accommodates the evidence. This network model accommodates neuropathological and neuroimaging evidence that dystonia may be associated with abnormalities in multiple different brain regions. It also accommodates animal studies showing that dystonic movements arise with manipulations of different brain regions. It is consistent with neurophysiological evidence suggesting defects in neural inhibitory processes, sensorimotor integration, and maladaptive plasticity. Finally, it may explain neurosurgical experience showing that targeting the basal ganglia is effective only for certain subpopulations of dystonia. Most importantly, the network model provides many new and testable hypotheses with direct relevance for new treatment strategies that go beyond the basal ganglia.

Dissecting the Links Between Cerebellum and Dystonia

“…Much of this understanding is based on the findings of overt basal ganglia lesions in neuroimaging and autopsy studies [1]. This localization of dystonia to the basal ganglia does not accommodate a growing body of clinical and experimental evidence of the involvement of other structures, and the concept of dystonia as a network disorder involving multiple brain regions has been proposed [2,3]. The role of the cerebellum in the pathophysiology of dystonia was first noted by Fletcher et al [4] and there is strong evidence of abnormal cerebellar function from pathological, neuroimaging, and neurophysiological studies [2,3,5], particularly in forms of primary dystonia [6][7][8].…”

“…Neychev et al [3] discuss the concept that irritative lesions to the cerebellum, which do not involve loss of cerebellar tissue but rather distort cerebellar output, can lead to dystonia. These lesions are likely to be focal hemorrhages or space-occupying lesions that compress and distort cerebellar functions, leading to an increase rather than a decrease in blood flow to the cerebellum [3,9]. The hypothesis is consistent with the relationship between dystonia and tremor because tremor is also viewed as a distortion of cerebellar functioning [2].…”

Dynamic head-neck stabilization in cervical dystonia

“…Although the pathophysiology of the disorder is not fully understood, dysfunction in the basal ganglia is thought to be the primary origin (Berardelli et al,1998;Breakefield et al,2008;Hallett,2006). Recent studies however have described the disorder as a network problem, involving other brain regions including the cerebellum, thalamus, midbrain and cerebral cortex (Neychev et al,2011). The involvement of abnormal sensory system features has led several researchers to suggest that CD is a sensorimotor disorder (Abbruzzese and Berardelli,2003;Breakefield et al,2008;Kanovsky et al,2003).…”

Non-invasive cerebellar stimulation in dystonia

“…Effects of non-invasive brain stimulation (NBS) to suppress M1 activity, either directly [13][14][15] or via premotor-M1 connections [16,17] have had mixed results to date. However, evidence of a wide network of brain dysfunction in the pathophysiology of dystonia that include the cerebellum [18][19][20][21][22], opens up the prospect of applying NBS to these novel targets. Furthermore, emerging evidence that the cerebellum is highly involved in moderating certain aspects of cognition [23,24] suggest that stimulating both motor …”