Аннотация:The relationship between two common movement disorders, dystonia and tremor, is controversial. Recent study showed biological differences in the basal ganglia network behavior in pure cervical dystonia or cervical dystonia combined with irregular head oscillationscompared with cervical dystonia with sinusoidal oscillations. We tested the hypothesis thatsinusoidal tremor has a different nature than jerky movements.We analized single unit activity of 1629 pallidal (GPi and GPe) cells, registered by microelectrode during DBS surgeries in 27 dystonic patients. We divided neurons into 3 groups– burst, pause, and tonic by means of an unsupervised clusterization. Then we calculated the firing rate, spike regularity, oscillation scores, burst and pause indexes, and otherparameters of pallidal cells. We also performed spectral analysis of local field potentials(LFP) recorded by means of externalized LEADs on the second day after DBS surgeries in5 dystonia patients. We compared parameters of pallidal activity between 3 groups: puredystonia (Dys) without tremor, dystonia with oscillatory tremor (OST) and dystonia withjerky movements (Jerky).We found robust differences in both firing rate and firing pattern of pallidal cells betweenOST and Jerky groups as well as between OST and Dys group and no differences betweenDys and Jerky group. We found significant increase of pause cells percentage in both GPi(11% in Dys, 9% in Jerky and 38% in OST) and GPe (16% in Dys, 14% in Jerky and 35% inOST) nuclei (fig 1 A). Burst and pause cells in OST group were also characterized by lowerfiring rate, higher irregularity and more bursty pattern compared to the other two groups(fig 1, B). The differences were observed in GPi in cervical dystonia and in GPe in generalized dystonia. Spectral analysis of LFP showed significantly higher theta and alpha oscillations in the OST group and higher low beta activity in the Dys group. We found significantincrease of theta activity in Jerky group, increase of alpha activity in Jerky and OST groupand no changes in Dyt group during voluntary head movement.Our results prove hypothesis that pure dystonia and dystonia with jerky movement havesimilar neurophysiological mechanisms while oscillatory tremor could be an additionalsymptom, having a different origin. On the other hand, our data showed that theta-alphaactivity, which has been considered as a biomarker for dystonia, appears to be a biomarkerfor dystonic tremor.The study was funded by the Russian Science Foundation (23-15-00487).