Cause of Tremor

[rayilynlee <rayilynlee@xxxxxxx>]

1st May 2008 - New research
the cause of tremor
Journal of Neurology Neurosurgery and Psychiatry [2008] 79 (5) : 514-521 
(Plaha P, Filipovic S, Gill SS.) Complete abstract

Precisely what happens in the brain when tremor occurs wass not clearly 
known. Researchers hypothesized that tremor in Parkinson's Disease occurs 
when two parts of the brain : the caudal zona incerta and the subthalamic 
nucleus are deprived of dopamine, and that they consequently become 
increasingly responsive to alpha and beta frequency oscillations. 
Oscillations are basically increases and decreases in stimulation. They 
tested their idea by stimulating the part of the brain they claimed to be 
responsible (the caudal zona incerta) with alpha and beta oscillations using 
deep brain stimulation (DBS) in people with Parkinson's Disease who did not 
have any tremor. DBS leads were also implanted in other sites within the 
brain. Tremor was produced by stimulating two parts of the brain (the caudal 
zona incerta and the ventrolateral thalamocortical neurons). Tremor was also 
seen following stimulation of the subthalamic nucleus, but only after very 
high levels of stimulation. No tremor was found after stimulating any other 
areas of the brain. The researchers consequently claim that tremor 
originates primarily via the caudal zona incerta and the ventrolateral 
thalamocortical neurons, instead of other areas in the brain in which it was 
previously assumed that tremor originated in Parkinson's Disease (in the 
cortico-ZI-VL-thalamocortical loop rather than in the 
cortico-basal-ganglia-thalamocortical loop).

Rayilyn Brown
Board Member AZNPF
Arizona Chapter National Parkinson's Foundation
rbrown@xxxxxxxxx 

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