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Background: There is a growing body of evidence suggesting that botulinum toxin can alter proprioceptive feedback and modulate the muscle‐spindle output for the treatment of dystonia. However, the mechanism for this modulation remains unclear. Methods: We conducted a study involving 17 patients with cervical dystonia (CD), seven of whom had prominent CD and 10 with generalized dystonia (GD) along with CD. We investigated the effects of neck vibration, a form of proprioceptive modulation, on spontaneous single‐neuron responses and local field potentials (LFPs) recorded from the globus pallidum externus (GPe) and internus (GPi). Results: Our findings demonstrated that neck vibration notably increased the regularity of neck‐sensitive GPi neurons in focal CD patients. Additionally, in patients with GD and CD, the vibration enhanced the firing regularity of non‐neck‐sensitive neurons. These effects on single‐unit activity were also mirrored in ensemble responses measured through LFPs. Notably, the LFP modulation was particularly pronounced in areas populated with burst neurons compared to pause or tonic cells. Conclusion: The results from our study emphasize the significance of burst neurons in the pathogenesis of dystonia and in the efficacy of proprioceptive modulation for its treatment. Moreover, we observed that the effects of vibration on focal CD were prominent in the α band LFP, indicating modulation of pallido‐cerebellar connectivity. Moreover, the pallidal effects of vibration in GD with CD involved modulation of cerebro‐pallidal θ band connectivity. Our analysis provides insight into how vibration‐induced changes in pallidal activity are integrated into the downstream motor circuit. © 2023 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Background: β Oscillations in the subthalamic nucleus (STN) have been proven to contribute to Parkinson's disease (PD), but the exact borders of β subbands vary substantially across the studies, and information regarding heterogeneity of β rhythmic activity is still limited. Recently, α oscillations in the basal ganglia have also become the focus of PD research. Objectives: The aim was to study rhythmic oscillations in the STN in PD patients to identify different subbands with stable oscillatory peaks within a broad α‐β range and to establish their associations with motor symptoms. Methods: Local field potentials inside the STN were recorded during deep brain stimulation (DBS) surgeries. After calculating power spectra and extracting an aperiodic component, oscillatory peaks in the 8‐ to 35‐Hz range with amplitude exceeding 90th percentile were clustered into three bands. Peak parameters were estimated for two lower subbands. Clinical features were compared in patients with and without oscillation peaks in the lowest α‐β subband. Results: We isolated α‐β (8–15 Hz), β (15–25 Hz), and β‐γ (25–35 Hz) subbands within the 8‐ to 35‐Hz spectral range using oscillatory parameters and Ward's hierarchical clustering. Additional α‐β oscillatory peaks were found in about half of patients with β peaks; they were located more ventrally compared to β. We have found a significant increase in disease duration, bradykinesia, and rigidity scores in the group with additional α‐β peaks. Conclusions: Increased α‐β oscillations may emerge as additional phenomena complementing β oscillations; they may mark disease progression in PD and affect DBS stimulation setup. © 2023 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Beta oscillations in basal ganglia are considered to contribute to motor dysfunction in Parkinson's disease (PD). However, there is a high variety in frequency borders for beta oscillations between studies, which complicates the comparison and interpretation of results. Here we aimed to study the homogeneity of oscillations in the broad "beta" range (8–30 Hz) and their implication to motor functioning in PD. For this purpose, we recorded local field potentials (LFP) in the subthalamic nucleus (STN) during 34 deep brain stimulation surgeries. We identified spectral features of LFP recordings in the range 8–30 Hz to search for candidate sub‐regions of stable oscillations and assessed their association with clinical scores on the contralateral side of the body and sensitivity to motor tests. Lower frequency oscillations (8–16 Hz) had a significant positive association with bradykinesia score. During voluntary movements, we observed a significant increase in LFP power in the 12–16 Hz range and a decrease in the 18–26 Hz range. We may conclude that the 8–30 Hz oscillation range includes oscillations with different functional features—sensitivity and responsiveness to movement, and clinical symptoms, which should be taken into account in further studies of beta oscillations association with PD pathophysiology. These data assume the coexistence of several frequency domains within beta range that are modulated in different ways under dopaminergic regulation and motor processing in human STN. [ABSTRACT FROM AUTHOR]

Periodic features of local field potentials (LFP) are extensively studied to establish the pathophysiological features contributing to Parkinson's disease (PD). Pathological LFP synchronization in the subthalamic nucleus (STN) was assumed to link with motor signs of PD. Commonly, the association between oscillations and clinical signs is studied while the patients are at rest. However, changes in LFPs during movement may reflect particular traits of motor processing in the basal ganglia under PD. Recently, the aperiodic 1/f broadband component of LFP spectra has attracted the attention of researchers because it may provide meaningful information about the neural activity in the brain. Here, we compared LFP signals in the STN of parkinsonian patients at rest and during hand movements occasionally followed by leg movements using two approaches, one of which accounts for the aperiodic features of LFP spectra. Using both methods, a significant increase was observed in synchronization in the low beta range during sequent leg but not hand movements. For either movement, there was a significant increase in gamma range synchronization using uncorrected power spectra and a significant decrease in the slope of the aperiodic component for the 1/f‐corrected method. These findings may support the claim that the 1/f slope possibly reflects the excitatory/inhibitory projections ratio in the recording site. Only the difference in the slope correlated significantly with motor signs of PD. These data show that the slope of aperiodic component may be a useful measure that is sensitive to the specific state and its changes in the brain. [ABSTRACT FROM AUTHOR]