2024-03-29T05:56:41Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1036582022-11-03T12:23:25Zcom_10261_31565com_10261_4com_10261_54com_10261_1col_10261_31566col_10261_307
00925njm 22002777a 4500
dc
Gallego, Juan Álvaro
author
Dideriksen, Jakob L.
author
Holobar, Ales
author
Ibáñez Pereda, Jaime
author
Pons Rovira, José Luis
author
Louis, Elan D.
author
Rocón, Eduardo
author
Farina, Dario
author
2014-10-01
Tremor in essential tremor (ET) is generated by pathological oscillations at 4 to 12 Hz, likely originating at cerebello-thalamo-cortical pathways. However, the way in which tremor is represented in the output of the spinal cord circuitries is largely unknown because of the difficulties in identifying the behavior of individual motor units from tremulous muscles. By using novel methods for the decomposition of multichannel surface EMG, we provide a systematic analysis of the discharge properties of motor units in 9 ET patients, with concurrent recordings of EEG activity. This analysis allowed inferring the contribution of common synaptic inputs to motor neurons in ET. Motor unit short-term synchronization was significantly greater in ET patients than in healthy subjects. Further, the strong association between the degree of synchronization and the peak in coherence between motor unit spike trains at the tremor frequency indicated that the high synchronization levels were generated mainly by common synaptic inputs specifically at the tremor frequency. The coherence between EEG and motor unit spike trains demonstrated the presence of common cortical input to the motor neurons at the tremor frequency. Nonetheless, the strength of this input was uncorrelated to the net common synaptic input at the tremor frequency, suggesting a contribution of spinal afferents or secondary supraspinal pathways in projecting common input at the tremor frequency. These results provide the first systematic analysis of the neural drive to the muscle in ET and elucidate some of its characteristics that determine the pathological tremulous muscle activity.
Journal of Neurophysiology 113 (1): 182-191 (2015)
http://hdl.handle.net/10261/103658
10.1152/jn.00531.2014
http://dx.doi.org/10.13039/501100000780
Influence of common synaptic input to motor neurons on the neural drive to muscle in essential tremor