Cortical Potentials and Parkinsonian Tremor

Alberts, W. Watson; Wright, Elwood W.; Feinstein, B.

doi:10.1038/221670a0

Cited by 80 publications

(53 citation statements)

References 5 publications

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“…There is little support for tremor-related activity in the striatum. Transmission through the corticosubthalamic pathway, however, is supported by the presence of oscillations in the subthalamic nucleus of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated monkeys (25) and in field potential recordings in the human motor cortex (26). Upon reaching the pallidum the activity could be desynchronized by populations of pallidal neurons, acting as independent nonlinear filters.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of tremor-related oscillations in the human globus pallidus: A single case study

Hurtado

Gray

Tamas

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

223

148

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Physiological evidence indicates that the resting tremor of Parkinson's disease originates in oscillatory neural activity in the forebrain, but it is unknown whether that activity is globally synchronized or consists of parallel, independently oscillating circuits. In the present study, we used dual microelectrodes to record tremor-related neuronal activity from eight sites in the internal segment of the globus pallidus (GPi) from an awake Parkinson's disease patient undergoing stereotaxic pallidotomy. We utilized spectral analysis to evaluate the temporal correlations between multiunit activity at spatially separated sites and between neural and limb electromyographic activity. We observed that some GPi neural pairs oscillated synchronously at the tremor frequency, whereas other neural pairs oscillated independently. Additionally, we found that GPi tremor-related activity at a given site could f luctuate between states of synchronization and independence with respect to upper limb tremor. Consistent with this finding, some paired recording sites within GPi showed periods of transient synchronization. These observations support the hypothesis of independent tremorgenerating circuits whose coupling can f luctuate over time.The motor disorders of Parkinson's disease (PD) and their relief by pallidotomy implicate the basal ganglia in the control of movement. However, neither the nature of the basal ganglia's role in movement control nor the neural mechanisms that underlie this role or the deficits in PD are understood. Most neurophysiological investigations of basal ganglia function and PD symptoms have focused on the mean firing rates of neurons as a descriptive parameter of neural activity. However, this approach limits the assessment of neuronal interactions and their temporal properties. A more thorough understanding of basal ganglia activity and the dynamic symptoms of PD, such as tremor and drug-induced dyskinesia, requires a finer analysis of the temporal structure of neuronal and neuromuscular interactions. This approach has recently been successfully applied to the study of pallidal activity in a primate model of PD (1). Here, we have applied spectral analysis to study the temporal properties of tremor-related activity in the globus pallidus in a single patient undergoing stereotactic pallidotomy.Parkinsonian tremor consists of a rhythmic (4-to 8-Hz) activation of muscles, more prominent in distal musculature, that is manifested under resting conditions and in some cases when maintaining posture. This symptom is one of the cardinal features of PD and occurs in about 75% of the cases (2, 3). ''Tremor-related activity'' is defined as rhythmic neural activity at a frequency in the range of parkinsonian tremor; it does not imply that the neural activity is phase-locked to the tremor. Although tremor-related activity in the basal ganglia and motor thalamus has been reported by many authors, in only a few cases has the temporal relationship between the neural and muscle activity been rigorously examined ...

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Section: Discussionmentioning

confidence: 99%

Dynamics of tremor-related oscillations in the human globus pallidus: A single case study

Hurtado

Gray

Tamas

et al. 1999

Proc. Natl. Acad. Sci. U.S.A.

223

148

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“…If neurons that do not work properly are in the circuits of the motor functions, this implies a dysfunction of the motor system, which results in conditions such as Parkinson's Disease (PD) [5,6]. In PD the neurons start firing themselves collectively in a periodic manner due to the loss of dopamine secretion [7], and this is the cause of the resting tremor (RT), being characteristic of PD in 70% of patients [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Resting tremor classification and detection in Parkinson's disease patients

Cámara

Isasi

Warwick

et al. 2015

Biomedical Signal Processing and Control

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Parkinson is a neurodegenerative disease, in which tremor is the main symptom. This paper investigates the use of different classification methods to identify tremors experienced by Parkinsonian patients. Some previous research has focussed tremor analysis on external body signals (e.g., electromyography, accelerometer signals, etc.). Our advantage is that we have access to sub-cortical data, which facilitates the applicability of the obtained results into real medical devices since we are dealing with brain signals directly.Local field potentials (LFP) were recorded in the subthalamic nucleus of 7 Parkinsonian patients through the implanted electrodes of a deep brain stimulation (DBS) device prior to its internalization. Measured LFP signals were preprocessed by means of splinting, down sampling, filtering, normalization and rectification. Then, feature extraction was conducted through a multi-level decomposition via a wavelet transform. Finally, artificial intelligence techniques were applied to feature selection, clustering of tremor types, and tremor detection.The key contribution of this paper is to present initial results which indicate, to a high degree of certainty, that there appear to be two distinct subgroups of patients within the group-1 of patients according to the Consensus Statement of the Movement Disorder Society on Tremor. Such results may well lead to different resultant treatments for the patients involved, depending on how their tremor has been classified.Moreover, we propose a new approach for demand driven stimulation, in which tremor detection is also based on the subtype of tremor the patient has. Applying this knowledge to the tremor detection problem, it can be concluded that the results improve when patient clustering is applied prior to detection.

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“…As one can see from (8), for K = 0, the optimal solution is stable, having two eigenvalues λ 0 = 0 and λ 1 = −C. The zero eigenvalue λ 0 is always a solution of the characteristic equation and corresponds to the shift of the phase (t) by a constant, to which solutions of (4) are insensitive.…”

Section: In Variables Of Amplitude R(t) and Phase (T) W(t) = R(t) Exmentioning

confidence: 99%

“…In contrast, pathologically strong synchronization processes may severely impair brain function. For instance, resting tremor in Parkinson's disease is caused by a synchronized population of oscillatory neurons, which collectively fire in a periodic manner [8,9]. In a magnetoencephalography (MEG) study, it has been shown that, in a patient with tremor-dominant Parkinson's disease, contralateral premotor and motor cortical activity in the range of twice the tremor frequency was phase synchronized with the electromyographic (EMG) tremor activity [10].…”

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confidence: 99%

Impact of Nonlinear Delayed Feedback on Synchronized Oscillators

2008

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We show that synchronization processes can effectively be controlled with nonlinear delayed feedback. We demonstrate that nonlinear delayed feedback can have a twofold impact on the collective dynamics of large ensembles of coupled oscillators: synchronizing and, mostly, desynchronizing effects. By means of a model equation for the mean field, we explore the existence and stability of the feedback-induced desynchronized states, their multistability and dynamical properties. We propose nonlinear delayed feedback stimulation for the therapy of neurological diseases characterized by abnormal synchrony.

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Cortical Potentials and Parkinsonian Tremor

Cited by 80 publications

References 5 publications

Dynamics of tremor-related oscillations in the human globus pallidus: A single case study

Dynamics of tremor-related oscillations in the human globus pallidus: A single case study

Resting tremor classification and detection in Parkinson's disease patients

Impact of Nonlinear Delayed Feedback on Synchronized Oscillators

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