Cross-frequency phase-amplitude coupling in repetitive movements in patients with Parkinson’s disease

Abstract

Bradykinesia is a cardinal motor symptom in Parkinson's disease (PD), the pathophysiology of which is not fully understood. We analyzed the role of cross-frequency coupling of oscillatory cortical activity in motor impairment in PD patients and healthy controls. High-density EEG signals were recorded during various motor activities and at rest. Patients performed a repetitive finger pressing task normally, but were slower than controls during tapping. Phase-amplitude coupling (PAC) between β (13-30Hz) and broadband γ (50-150Hz) was computed from individual EEG source signals in the premotor, primary motor, and primary somatosensory cortices, and the primary somatosensory complex. In all four regions, averaging the entire movement period resulted in higher PAC in patients than in controls for the resting condition and the pressing task (similar performance between groups). However, this was not the case for the tapping tasks where patients performed slower. This suggests the strength of state-related β-γ PAC does not determine Parkinsonian bradykinesia. Examination of the dynamics of oscillatory EEG signals during motor transitions revealed a distinctive motif of PAC rise and decay around press onset. This pattern was also present at press offset and slow tapping onset, linking such idiosyncratic PAC changes to transitions between different movement states. The transition-related PAC modulation in patients was similar to controls in the pressing task but flattened during slow tapping, which related to normal and abnormal performance, respectively. These findings suggest that the dysfunctional evolution of neuronal population dynamics during movement execution is an important component of the pathophysiology of Parkinsonian bradykinesia.

Temporal Ablation of the Ciliary Protein IFT88 Alters Normal Brainwave Patterns

“…It was found that phase-amplitude coupling (PAC) between the theta and high-gamma frequencies was impaired in awake and in non-REM sleep of inducible IFT88 KO mice. PAC, specifically between the theta-gamma bandwidths, has a well-established role in memory formation and is known to be disrupted in humans afflicted with mild cognitive impairment, Alzheimer’s, and Parkinson’s [25], [44][45]. Based off these data we can postulate that inducible IFT88 KO mice will have impaired memory formation, which has been recorded in preliminary behavioral experiments [46].…”

Predicting Motor Vigor from EEG Phase Amplitude Coupling (PAC) in Parkinson’s Disease: Effects of Dopaminergic Medication and Non-invasive Modulation

“…Prior works on PAC in PD have focused on rest, but a recent study demonstrated that beta-gamma PAC was altered during transitions between different movement states (Gong et al, 2022). Our results show that PAC, at multiple frequency combinations, is directly related to MV, even in a single, overlearned task which would not necessarily involve switching between movement states.…”

“…The complete pipeline of analysis carried out is shown in Figure 2. Initially, the PAC value (See supplementary Material section 2) for each pair of the five standard EEG subbands-Delta (0.5-4 Hz), Theta (4-8 Hz), Alpha (8-16 Hz), Beta (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32), and Gamma (32-45 Hz)-was calculated to create a 2-dimensional representation of PAC values using TensorPAC [36], an open-source Python library for PAC investigation of neurophysiological data. Subsequently, we used the VGG-16 architecture [37] for transfer learning (called PACNET) to train a model to predict MV.…”

“…While most studies examining altered PAC in PD have focused on rest, a recent study demonstrated that beta-gamma PAC was altered during transitions between different movement states, with the speculation that this was related to bradykinesia in PD (Gong et al, 2022). Here, we explore an alternate hypothesis, namely that PAC, and not just beta-gamma PAC, is directly associated with MV, as opposed to movement transitions.…”

Assess stimulation-induced dyskinesia and its potential physiological mechanism using phase-amplitude coupling

“…To be noted, a number of theoretical theories and laboratory results has shown the significance of interactions between activities occurring at various frequencies, especially in processing and transmissing information. However, to find the exact relationship between different frequency bandwidth require methods different from the traditional way of processing information such as wavelet convolution or STFT, which always focus on the independent oscillatory activity and therefore very hard to show the relationship between different frequency bands and even across different neural nucleus, as shown in the figure2 [8]. The coupling between theta and gamma in the hippocampus of rodents is one of the most well-studied examples of cross-frequency coupling (CFC).…”