Clinical Neurophysiology
September 21, 2011
Aviva Berkovich-Ohana, Joseph Glicksohn, Abraham Goldstein
309 citations
Mindfulness meditation practitioners show lower frontal gamma brain activity, indicating reduced default mode network (DMN) engagement and less self-referential thinking, both as a lasting trait and during a time production task. They also produce longer time estimates, which correlate with lower frontal gamma. Additionally, they exhibit increased posterior gamma power, suggesting heightened attention and sensory awareness. These effects appear regardless of meditation proficiency, suggesting neuroplastic changes in self-referential and attentional networks from early practice stages. The findings demonstrate that EEG can non-invasively measure DMN activity.
Clinical Neurophysiology
June 15, 2010
Yun Qin, Peng Xu, Dezhong Yao
207 citations
Choosing the reference electrode for EEG recordings substantially affects measures of brain activity, including the default mode network (DMN). Simulated data showed that the infinity reference obtained by the reference electrode standardisation technique (REST) exactly recovered the true network configuration. In real EEG data from 15 participants, different references—REST, average reference, linked mastoids, and left mastoid—produced significant differences in power spectra, coherence, and DMN connectivity. Compared with REST, the average reference strengthened long-distance connections between anterior and posterior brain areas, while linked mastoids and left mastoid references disrupted posterior connectivity. The effects depended on EEG frequency band. REST is a valid reference technique for objective comparisons across studies and clinical practice.
Clinical Neurophysiology
March 14, 2021
Torsten M. Meyer, Martin Brunovský, Jiřı́ Horáček et al.
25 citations
In patients with major depressive disorder, heart rate and heart rate variability measured before and during ketamine infusion can predict who will respond to treatment. Among 51 patients, those who responded to ketamine had a higher heart rate throughout the study, including at baseline, compared to non-responders. Ketamine infusion increased both heart rate and heart rate variability power during and after infusion. Heart rate and heart rate variability power, but not normalized frequency bands, discriminated between responders and non-responders. These findings suggest that autonomic nervous system markers may help optimize treatment selection for major depressive disorder.
Clinical Neurophysiology
October 1, 2021
Shubham Chamadia, Jacob Gitlin, Jennifer Mekonnen et al.
Ketamine anesthesia produces structured changes in brain electrical activity that track anesthetic state but not dissociation. In an open-label study of 15 participants given 2 mg/kg ketamine, unresponsiveness was linked to increased frontal brainwave power across several frequency bands, while a responsive but dissociated state showed decreased power across broad ranges. The benzodiazepine midazolam reduced dissociation scores and altered power in specific bands. A mixed-effects model found that only midazolam, not any electroencephalogram feature, predicted dissociation scores. The authors conclude that electroencephalogram signatures may enable principled monitoring of anesthetic state but not dissociation.
Clinical Neurophysiology
November 27, 2019
O. Gosseries, M. Fecchio, Audrey Wolff et al.
A single highly trained expert in cognitive trance—a self-induced, focused state of consciousness—underwent transcranial magnetic stimulation combined with electroencephalography during normal wakefulness and during trance. The trance state was induced using a standardized protocol of body movements and vocalizations. Compared to resting wakefulness, the electrical reactivity of cortical circuits to magnetic pulses changed during trance, with differences measured across frontal and parietal brain areas. The findings suggest that cognitive trance alters the brain's electrical responses to external perturbations, offering insight into the neurophysiology of this state.