Altered Activation in Cerebellum Contralateral to Unilateral Thalamotomy May Mediate Tremor Suppression in Parkinson's Disease: A Short-Term Regional Homogeneity fMRI Study.
BACKGROUND
Ventral intermediate nucleus thalamotomy is an effective treatment for Parkinson's disease tremor. However, its mechanism is still unclear.


OBJECTIVE
We used resting-state fMRI to investigate short-term ReHo changes after unilateral thalamotomy in tremor-dominant PD, and to speculate about its possible mechanism on tremor suppression.


METHODS
26 patients and 31 healthy subjects (HS) were recruited. Patients were divided into two groups according to right- (rPD) and left-side (lPD) thalamotomy. Tremor was assessed using the 7-item scale from the Unified Parkinson's disease rating scale motor score (mUPDRS). Patients were scanned using resting state fMRI after 12h withdrawal of medication, both preoperatively (PDpre) and 7- day postoperatively (PDpost), whereas healthy subjects were scanned once. The regions associated with tremor and altered ReHo due to thalamic ablation were examined.


RESULTS
The impact of unilateral VIM thalamotomy was characterized in the frontal, parietal, temporal regions, basal ganglia, thalamus, and cerebellum. Compared with PDpre, significantly reduced ReHo was found in the left cerebellum in patients with rPDpost, and slightly decreased ReHo in the cerebellum vermis in patients with lPDpost, which was significantly higher than HS. We demonstrated a positive correlation between the ReHo values in the cerebellum (in rPD, peak coordinate [-12, -54, -21], R = 0.64, P = 0.0025, and peak coordinate [-9, -54, -18], R = 0.71, P = 0.0025; in lPD, peak coordinate [3, -45, -15], R = 0.71, P = 0.004) in the pre-surgical condition, changes of ReHo induced by thalamotomy (in rPD, R = 0.63, P = 0.021, R = 0.6, P = 0.009; in lPD, R = 0.58, P = 0.028) and tremor scores contralateral to the surgical side, respectively.


CONCLUSIONS
The specific area that may be associated with PD tremor and altered ReHo due to thalamic ablation is the cerebellum. The neural basis underlying thalamotomy is complex; cerebellum involvement is far beyond cerebello-thalamic tract breakage.
Department of Magnetic Resonance Imaging, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
Zhi
Z
Wen
Department of Neurosurgery, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
Jie
J
Zhang
Department of Magnetic Resonance Imaging, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
Jielan
J
Li
National Center for Magnetic Resonance, Key State Laboratory of Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Hubei, China.|University of Chinese Academy of Sciences, Beijing, China.
Jiankun
J
Dai
National Center for Magnetic Resonance, Key State Laboratory of Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Hubei, China.
Fuchun
F
Lin
Department of Magnetic Resonance Imaging, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China.
Guangyao
G
Wu
D000368:Aged; D001479:Basal Ganglia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D016022:Case-Control Studies; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010296:Parietal Lobe / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D010300:Parkinson Disease / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D011597:Psychomotor Performance; D012107:Research Design; D013702:Temporal Lobe / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D014202:Tremor / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery; D020651:Ventral Thalamic Nuclei / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology* / Q000601:surgery