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It is well established that providing visual guidance within demonstration models positively influences the quality of kinesthetic motor imagery (kMI) for complex motor skills. Given that action execution and kMI share several underlying mechanisms, we hypothesize that color-coded visual cues indicating muscle activation in demonstration models can enhance the quality of kMI in the acquisition of complex motor skills. To test this hypothesis. We employed AnyBody Modeling System to develop demonstration model videos of complex motor skills. Thirty participants (mean age = 20.3 ± 0.6 years; 7 men and 8 women per group) were assigned to an experimental group, which engaged in kMI after viewing demonstration videos supplemented with simulated muscle activation color cues, or to a control group, which performed kMI following videos without such cues. All participants scored above 5 on the Motor Imagery Questionnaire-2 (MIQ-2). The vividness of kMI was assessed using the Vividness of Motor Imagery Questionnaire-2 (VMIQ-2). A 64-channel EEG cap was utilized for data acquisition. Changes in alpha and beta range oscillations during kMI were examined, and region of interest (ROI) analysis was conducted to extract the correlation coefficient matrix among kMI-related subcortical nuclei. Our results demonstrated that the vividness of kMI in the experimental group was significantly higher than that in the control group by 19.9 % (P < 0.05). Conversely, alpha event-related synchronization (ERS) in the parietal and occipital regions, as well as ERS in the frontal, central, and temporal regions, were significantly lower in the experimental group compared to the control group. The source-functional connectivity results revealed that the primary differences between the experimental and control groups were concentrated between the left V1 and right V1, as well as among the posterior parietal cortex (PPC), dorsolateral prefrontal cortex (DLPFC), and primary motor cortex (M1). In conclusion, the demonstration model, which incorporates simulated muscle activation and color visualization, enhances the vividness of kMI in complex motor skills. This enhancement is associated with the selective inhibition of the frontal, central, and temporal brain regions, the activation of the occipital and parietal regions within brain rhythmic activity, and increased information flow between the occipital-parietal and frontal-parietal brain regions.

Working Memory (WM) requires maintenance of task-relevant information and suppression of task-irrelevant/distracting information. Alpha and theta oscillations have been extensively investigated in relation to WM. However, studies that examine both theta and alpha bands in relation to distractors, encompassing not only power modulation but also connectivity modulation, remain scarce. Here, we depicted, at the EEG-source level, the increase in power and connectivity in theta and alpha bands induced by strong relative to weak distractors during a visual Sternberg-like WM task involving the encoding of verbal items. During retention, a strong or weak distractor was presented, predictable in time and nature. Analysis focused on the encoding and retention phases before distractor presentation. Theta and alpha power were computed in cortical regions of interest, and connectivity networks estimated via spectral Granger causality and synthetized using in/out degree indices. The following modulations were observed for strong vs. weak distractors. In theta band during encoding, the power in frontal regions increased, together with frontal-to-frontal and bottom-up occipital-to-temporal-to-frontal connectivity; even during retention, bottom-up theta connectivity increased. In alpha band during retention, but not during encoding, the power in temporal-occipital regions increased, together with top-down frontal-to-occipital and temporal-to-occipital connectivity. From our results, we postulate a proactive cooperation between theta and alpha mechanisms: the first would mediate enhancement of target representation both during encoding and retention, and the second would mediate increased inhibition of sensory areas during retention only, to suppress the processing of imminent distractor without interfering with the processing of ongoing target stimulus during encoding.

Background: Fluctuating neuronal network states influence brain responses to transcranial magnetic stimulation (TMS). Our previous studies revealed that transient spontaneous bihemispheric brain states in the EEG, driven by oscillatory power, information flow and regional domination, modify cortical EEG responses to TMS. However, the impact of ongoing fluctuations of large-scale brain network states on TMS-EEG responses has not been explored. Objectives: To determine the effects of large-scale brain network states on TMS-EEG responses. Methods: Resting-state EEG and structural MRI from 24 healthy subjects were recorded to infer large-scale brain states. TMS-EEG was acquired with TMS at state-related targets, identified by the spatial distribution of state activation power from resting-state EEG. TMS-induced oscillations were measured by event-related spectral perturbations (ERSPs), and classified with respect to the brain states preceding the TMS pulses. State-locked ERSPs with TMS at specific state-related targets and during state activation were compared with state-unlocked ERSPs. Results: Intra-individual comparison of ERSPs by threshold free cluster enhancement (TFCE) revealed that posterior and visual state-locked TMS, respectively, increased beta and alpha responses to TMS of parietal and occipital cortex compared to state-unlocked TMS. Also, the peak frequencies of ERSPs were increased with state-locked TMS. In addition, inter-individual correlation analyses revealed that posterior and visual state-locked TMS-induced oscillation power (ERSP clusters identified by TFCE) positively correlated with state-dependent oscillation power preceding TMS. Conclusions: Spontaneous transient large-scale brain network states modify TMS-induced natural oscillations in specific brain regions. This significantly extends our knowledge on the critical importance of instantaneous state on explaining the brain's varying responsiveness to external perturbation.

Different cortical regions respond with distinct rhythmic patterns of neural oscillations to Transcranial Magnetic Stimulation (TMS). We investigated natural frequencies induced by TMS in left and right homologous dorsolateral prefrontal cortices (DLPFC) and related hemispheric differences. In 12 healthy young adults, single-pulse TMS was delivered in different blocks close to F3 and F4 channels to target left and right DLPFC. An occipital site near PO3 was stimulated as control. TMS-related spectral perturbation analyses were performed on recorded EEG data. A widespread unspecific increase in theta power was observed for all stimulation sites. However, occipital TMS induced greater alpha activity and a 10.58 Hz natural frequency, while TMS over the left and right DLPFC resulted in similar beta band modulations and a natural frequency of 18.77 and 18.5 Hz, respectively. In particular, TMS-related specific increase in beta activity was stronger for the right than the left DLPFC. The right DLPFC is more specifically tuned to its natural beta frequency when it is directly stimulated by TMS than with TMS over the left counterpart (or a posterior region), while the left DLPFC increases its beta activity more similarly irrespective of whether it is directly stimulated or through right homologous stimulation. These results yield important implications for both basic neuroscience research on inter-hemispheric prefrontal interactions and clinical applications.

Objectives: Idiopathic REM sleep behavior disorder (iRBD) patients are susceptible to cognitive deficits, especially attention dysfunction. The objective of this study is to elucidate the neural mechanism of the dysfunction in attention known as 'inhibition of return' (IOR) in iRBD patients based on an analysis of oscillatory cortical activity during a selective attention task., Methods: Event-related potentials (ERPs) were recorded from iRBD patients and normal control subjects while performing a Posner task. The differences in N1 ERP and theta- and beta-bands event-related spectral perturbations (ERSPs) between valid and invalid stimuli were compared between groups., Results: The N1 amplitude was significantly higher for the invalid stimuli in controls, while the valid-invalid difference was not significant in iRBD patients. The valid-invalid differences in ERSPs were prominent in controls at ∼100-400 ms for the theta-band and ∼200-400 ms for the beta-band, and the valid-invalid differences in ERSPs were not significant in the iRBD patients., Conclusion: The results demonstrated that valid-invalid differences in neural activity were absent in iRBD patients, and these neural findings were in accord with the behavioral results., Significance: Our findings imply impairment in sensory-perceptual processing mediated by attentional control and response inhibition in early-stage iRBD before clinical neurodegeneration., (Copyright © 2019 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: To identify possible electroencephalographic (EEG) markers of donepezil's effect on cortical activity in young, healthy adult volunteers at the group level., Methods: Thirty subjects were administered a daily dose of either 5mg donepezil or placebo for 15days in a double-blind, randomized, cross-over trial. The electroencephalogram during an auditory oddball paradigm was recorded from 58 scalp electrodes. Current source density (CSD) transformations were applied to EEG epochs. The event-related potential (ERP), inter-trial coherence (ITC: the phase consistency of the EEG spectrum) and event-related spectral perturbation (ERSP: the EEG power spectrum relative to the baseline) were calculated for the target (oddball) stimuli., Results: The donepezil and placebo conditions differed in terms of the changes in delta/theta/alpha/beta ITC and ERSP in various regions of the scalp (especially the frontal electrodes) but not in terms of latency and amplitude of the P300-ERP component., Conclusion: Our results suggest that ITC and ERSP analyses can provide EEG markers of donepezil's effects in young, healthy, adult volunteers at a group level., Significance: Novel EEG markers could be useful to assess the therapeutic potential of drug candidates in Alzheimer's disease in healthy volunteers prior to the initiation of Phase II/III clinical studies in patients., (Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)

Objective: We investigated neuronal correlates of faces versus non-faces processing in a cortically blind patient (TN) and a group of healthy age-matched controls in order to test electrophysiological correlates of the processing of pertinent stimuli in this patient., Methods: An EEG paradigm was used, in which intact and scrambled faces were displayed on a screen. First, time-frequency transforms were conducted on the patients' data alone. These oscillations were then compared to the frontal activity of six control participants., Results: Post stimulus oscillatory modulations (synchronisation in theta and alpha frequency bands) of both intact and scrambled faces at frontal scalp sites were observed in TN. These modulations were different for correct and incorrect responses. A more important increase in the theta band for incorrect responses was observed. The oscillatory rhythms highlighted in blindsight and in frontal regions differ from the ones observed in control participants., Conclusion: Despite the destruction of the visual cortex, oscillatory rhythms are not cancelled out but are shifted to anterior regions, revealing the activity of an alternate pathway for residual visual function., Significance: The results provide evidence for a top-down cognitive control process in blindsight., (Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.)