Dataset Information

Pallidal low β-low γ phase-amplitude coupling inversely correlates with Parkinson disease symptoms.

ABSTRACT:

Objective

Recent discoveries suggest that it is most likely the coupling of β oscillations (13-30Hz) and not merely their power that relates to Parkinson disease (PD) pathophysiology.

Methods

We analyzed power and phase amplitude coupling (PAC) in local field potentials (LFP) recorded from Pallidum after placement of deep brain stimulation (DBS) leads in nineteen PD patients and three patients with dystonia.

Results

Within GPi, we identified PAC between phase of β and amplitude of high frequency oscillations (200-300Hz) and distinct β-low γ (40-80Hz) PAC both modulated by contralateral movement. Resting β-low γ PAC, also present in dystonia patients, inversely correlated with severity of rigidity and bradykinesia (R=-0.44, P=0.028). These findings were specific to the low β band, suggesting a differential role for the two β sub-bands.

Conclusions

PAC is present across distinct frequency bands within the GPi. Given the presence of low β-low γ PAC in dystonia and the inverse correlation with symptom severity, we propose that this PAC may be a normal pallidal signal.

Significance

This study provides new evidence on the pathophysiological contribution of local pallidal coupling and suggests similar and distinct patterns of coupling within GPi and STN in PD.

SUBMITTER: Tsiokos C

PROVIDER: S-EPMC5675765 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature

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Publications

Pallidal low β-low γ phase-amplitude coupling inversely correlates with Parkinson disease symptoms.

Tsiokos Christos C Malekmohammadi Mahsa M AuYong Nicholas N Pouratian Nader N

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology 20170905 11

<h4>Objective</h4>Recent discoveries suggest that it is most likely the coupling of β oscillations (13-30Hz) and not merely their power that relates to Parkinson disease (PD) pathophysiology.<h4>Methods</h4>We analyzed power and phase amplitude coupling (PAC) in local field potentials (LFP) recorded from Pallidum after placement of deep brain stimulation (DBS) leads in nineteen PD patients and three patients with dystonia.<h4>Results</h4>Within GPi, we identified PAC between phase of β and ampli ...[more]

PMID: 28942154

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Project description:Postictal generalized EEG suppression is the state of suppression of electrical activity at the end of a seizure. Prolongation of this state has been associated with increased risk of sudden unexpected death in epilepsy, making characterization of underlying electrical rhythmic activity during postictal suppression an important step in improving epilepsy treatment. Phase-amplitude coupling in EEG reflects cognitive coding within brain networks and some of those codes highlight epileptic activity; therefore, we hypothesized that there are distinct phase-amplitude coupling features in the postictal suppression state that can provide an improved estimate of this state in the context of patient risk for sudden unexpected death in epilepsy. We used both intracranial and scalp EEG data from eleven patients (six male, five female; age range 21-41 years) containing 25 seizures, to identify frequency dynamics, both in the ictal and postictal EEG suppression states. Cross-frequency coupling analysis identified that during seizures there was a gradual decrease of phase frequency in the coupling between delta (0.5-4 Hz) and gamma (30+ Hz), which was followed by an increased coupling between the phase of 0.5-1.5 Hz signal and amplitude of 30-50 Hz signal in the postictal state as compared to the pre-seizure baseline. This marker was consistent across patients. Then, using these postictal-specific features, an unsupervised state classifier-a hidden Markov model-was able to reliably classify four distinct states of seizure episodes, including a postictal suppression state. Furthermore, a connectome analysis of the postictal suppression states showed increased information flow within the network during postictal suppression states as compared to the pre-seizure baseline, suggesting enhanced network communication. When the same tools were applied to the EEG of an epilepsy patient who died unexpectedly, ictal coupling dynamics disappeared and postictal phase-amplitude coupling remained constant throughout. Overall, our findings suggest that there are active postictal networks, as defined through coupling dynamics that can be used to objectively classify the postictal suppression state; furthermore, in a case study of sudden unexpected death in epilepsy, the network does not show ictal-like phase-amplitude coupling features despite the presence of convulsive seizures, and instead demonstrates activity similar to postictal. The postictal suppression state is a period of elevated network activity as compared to the baseline activity which can provide key insights into the epileptic pathology.

Dataset Information

Pallidal low β-low γ phase-amplitude coupling inversely correlates with Parkinson disease symptoms.

Objective

Methods

Results

Conclusions

Significance

Publications

Pallidal low β-low γ phase-amplitude coupling inversely correlates with Parkinson disease symptoms.

Similar Datasets

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