Mu rhythm, also known as the mu wave, occurs on sensorimotor cortex activity at rest, and the frequency range is defined as 8–13Hz, the same frequency as the alpha band. Mu rhythm is a cortical oscillation that can be recorded from the scalp over the primary sensorimotor cortex by electroencephalogram (EEG) and magnetoencephalography (MEG). The subjects of previous mu/beta rhythm studies ranged widely from infants to young and older adults. Furthermore, these subjects were not only healthy people but also patients with various neurological and psychiatric diseases. However, very few studies have referred to the effect of mu/beta rhythm with aging, and there was no literature review about this theme. It is important to review the details of the characteristics of mu/beta rhythm activity in older adults compared with young adults, focusing on age-related mu rhythm changes. By comprehensive review, we found that, compared with young adults, older adults showed mu/beta activity change in four characteristics during voluntary movement, increased event-related desynchronization (ERD), earlier beginning and later end, symmetric pattern of ERD and increased recruitment of cortical areas, and substantially reduced beta event-related desynchronization (ERS). It was also found that mu/beta rhythm patterns of action observation were changing with aging. Future work is needed in order to investigate not only the localization but also the network of mu/beta rhythm in older adults.

To investigate the neurophysiological effects of minimal social co-presence on the Heartbeat Evoked Potential (HEP) and EEG dynamics, providing a normative baseline for altered interoception in clinical disorders. Thirty healthy adults performed a repetitive crafting task in "alone" and "parallel social presence" conditions. EEG and ECG were recorded, and HEPs plus time-frequency dynamics were compared using permutation testing. Changes in cardiac vagal activity and subjective stress were also assessed. Parallel co-presence significantly altered HEP morphology (reduced frontal negativity, central-parietal positivity) and EEG power (beta, theta, alpha bands). Only under parallel condition, frontal HEP amplitude correlated with increased cardiac vagal activity (r = 0.39) and reduced subjective stress (rS = -0.55). Minimal social context alters the brain's processing of cardiac signals and its autonomic relationship in healthy young adults, establishing a neurophysiological benchmark for brain-body-society interactions. As this study used a non-clinical sample, the findings are not direct evidence of HEP's clinical utility. This work provides a foundational baseline for future comparative studies needed to determine its potential as a clinical biomarker. This study is the first to demonstrate normative neurophysiological effects of minimal social presence on HEP, providing critical evidence and guidance for future clinical research.

Background: Patients' “pain attributions,” or their beliefs about chronic pain causes, critically affect pain experience and recovery, potentially modulating responses to analgesics and psychotropics. Since many pain‐mitigating drugs also impact psychological processes and brain functions underlying these attributions, such processes are relevant targets. The Chronic Pain Attribution Scale (CPAS) by Ashar et al. (2023) quantifies these beliefs. A Japanese version (CPAS‐J) is needed to assess this psychologically relevant construct in Japanese populations. This study aimed to develop and linguistically validate the CPAS‐J. Methods: The CPAS‐J was developed following International Society for Pharmacoeconomics and Outcomes Research guidelines, with permission from the original author. The process included forward translation by eight bilingual medical experts, reconciliation by a pain research team, back‐translation by an independent translator, review by the original author, and a final consensus discussion to establish the definitive CPAS‐J. Results: The linguistic validation identified challenges in distinguishing “cause” from “trigger” in Japanese. To enhance comprehensibility, the team combined “kikkake” (initiating factor) and “gen'in” (broader cause/origin). The finalized CPAS‐J assesses perceived causes of pain. Conclusions: The CPAS‐J was successfully developed through a rigorous process. This tool supports research on pain attributions in Japanese‐speaking populations and may improve our understanding of treatment responses by assessing a key psychological dimension of chronic pain that is linked to brain‐based processes.