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Updated: May 12, 2026

Assessment of Sensorimotor Function in Mouse Models of Parkinson's Disease
Published on: June 17, 2013
Serotonergic loss in motor circuitries correlates with severity of action-postural tremor in PD
Clare Loane1, Kit Wu, Peter Bain
1Department of Medicine, Division of Brain Sciences, Hammersmith Hospital, Imperial College London, UK.
Objective:
The underlying pathophysiology of tremor in Parkinson disease (PD) is unclear; however, it is known that tremor does not appear to be as responsive to dopaminergic medication as bradykinesia or rigidity. It is suggested that serotonergic dysfunction could have a role in tremor development.
Methods:
Using (11)C-DASB PET, a marker of serotonin transporter binding, and clinical observations, we have investigated function of serotonergic terminals in 12 patients with tremor-predominant and 12 with akinetic-rigid PD. Findings were compared with those of 12 healthy controls.
Results:
Reductions of (11)C-DASB in caudate, putamen, and raphe nuclei significantly correlated with tremor severity on posture and action, but not with resting tremor. The tremor-predominant group also showed reductions of (11)C-DASB in other regions involved in motor circuitry, including the thalamus and Brodmann areas 4 and 10.
Conclusions:
Our findings support a role for serotonergic dysfunction in motor circuitries in the generation of postural tremor in PD.
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