Revealing the dynamic causal interdependence between neural and muscular signals in Parkinsonian tremor. (In special issue: Medical Applications of Signal Processing, Part I)
Wang, S., Chen, Y., Ding, M., Feng, J., Stein, J.F., Aziz, T.Z. and Liu, X. (2007) Revealing the dynamic causal interdependence between neural and muscular signals in Parkinsonian tremor. (In special issue: Medical Applications of Signal Processing, Part I). Journal of the Franklin Institute, 344, (3-4), 180-195. (doi:10.1016/j.jfranklin.2006.06.003).
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Functional correlation between oscillatory neural and muscular signals during tremor can be revealed by coherence estimation. The coherence value in a defined frequency range reveals the interaction strength between the two signals. However, coherence estimation does not provide directional information, preventing the further dissection of the relationship between the two interacting signals. We have therefore investigated causal correlations between the subthalamic nucleus (STN) and muscle in Parkinsonian tremor using adaptive Granger autoregressive (AR) modeling. During resting tremor we analyzed the inter-dependence of local field potentials (LFPs) recorded from the STN and surface electromyograms (EMGs) recorded from the contralateral forearm muscles using an adaptive Granger causality based on AR modeling with a running window to reveal the time-dependent causal influences between the LFP and EMG signals in comparison with coherence estimation. Our results showed that during persistent tremor, there was a directional causality predominantly from EMGs to LFPs corresponding to the significant coherence between LFPs and EMGs at the tremor frequency; and over episodes of transient resting tremor, the inter-dependence between EMGs and LFPs was bi-directional and alternatively varied with time. Further time–frequency analysis showed a significant suppression in the beta band (10–30 Hz) power of the STN LFPs preceded the onset of resting tremor which was presented as the increases in the power at the tremor frequency (3.0–4.5 Hz) in both STN LFPs and surface EMGs. We conclude that the functional correlation between the STN and muscle is dynamic, bi-directional, and dependent on the tremor status. The Granger causality and time–frequency analysis are effective to characterize the dynamic correlation of the transient or intermittent events between simultaneously recorded neural and muscular signals at the same and across different frequencies.
|Keywords:||causality, coherence, autoregressive model, time–frequency, local field potential, electromyogram|
|Subjects:||R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
T Technology > TA Engineering (General). Civil engineering (General)
|Divisions:||University Structure - Pre August 2011 > Institute of Sound and Vibration Research > Human Sciences
|Date Deposited:||12 Jul 2007|
|Last Modified:||02 Mar 2012 13:08|
|Contributors:||Wang, S. (Author)
Chen, Y. (Author)
Ding, M. (Author)
Feng, J. (Author)
Stein, J.F. (Author)
Aziz, T.Z. (Author)
Liu, X. (Author)
|Contact Email Address:||email@example.com|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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