Science
September 29, 2005
Marcello Massimini, Fabio Ferrarelli, Reto Huber et al.
1,603 citations
During non-rapid eye movement sleep, the brain's response to a direct cortical stimulus is stronger but fails to propagate beyond the stimulation site, unlike during quiet wakefulness when the activation spreads to distant connected areas. This breakdown in cortical effective connectivity may explain why consciousness fades during certain sleep stages despite ongoing brain activity.
The International Journal of Neuropsychopharmacology
June 7, 2012
Wallace C. Duncan, Simone Sarasso, Fabio Ferrarelli et al.
253 citations
A single infusion of the NMDA receptor antagonist ketamine rapidly reduces depressive symptoms in patients with treatment-resistant major depressive disorder. In 30 patients, ketamine increased electroencephalogram slow wave activity during early non-REM sleep and raised plasma levels of brain-derived neurotrophic factor. The occurrence of high amplitude slow waves and their slope also increased, indicating enhanced synaptic strength. Changes in BDNF levels correlated with changes in EEG parameters, but only in patients who responded to ketamine. This suggests that enhanced synaptic plasticity, reflected by increased slow wave activity and BDNF, is part of the mechanism behind ketamine's rapid antidepressant effects.
Cognitive Neuroscience
July 1, 2010
Marcello Massimini, Fabio Ferrarelli, Michael J. Murphy et al.
205 citations
During the first REM sleep episode of the night, transcranial magnetic stimulation (TMS) triggered widespread and differentiated patterns of cortical activation on electroencephalography (EEG), similar to those observed during wakefulness. In contrast, during NREM sleep, cortical activations became more local and stereotypical, indicating impaired intracortical dialogue. These findings suggest that TMS combined with high-density EEG can probe the internal dialogue of the thalamocortical system, potentially offering a method to assess brain function in patients who are unable to move or communicate.
PLoS ONE
August 28, 2013
Fabio Ferrarelli, Richard Smith, Daniela Dentico et al.
125 citations
Long-term Buddhist meditators with about 8,700 mean lifetime hours of practice show increased gamma power (25-40 Hz) in parietal-occipital regions during non-rapid eye movement sleep compared to meditation-naive individuals. This increase is specific to gamma frequencies, unrelated to spontaneous arousal levels during NREM sleep, and positively correlated with the length of lifetime daily meditation practice. The findings indicate that meditation practice produces measurable changes in spontaneous brain activity and suggest that EEG gamma activity during sleep may serve as a sensitive marker of long-lasting plastic effects of meditative training on brain function.
PLoS ONE
February 22, 2016
Daniela Dentico, Fabio Ferrarelli, Brady A. Riedner et al.
43 citations
After two intensive days of mindfulness or compassion meditation, long-term meditators showed increased low-frequency brain activity (1-12 Hz, peaking around 7-8 Hz) over prefrontal and left parietal areas during non-rapid eye movement sleep. This increase was strongest early in the night and extended to higher frequencies (25-40 Hz) during the third sleep cycle. The changes depended on meditation experience and did not differ between the two meditation styles. No such changes occurred in meditation-naive individuals. The findings suggest that intensive meditation practice acutely alters brain activity in regions linked to top-down regulation, complementing chronic changes seen in posterior areas.
European Journal of Neuroscience
August 24, 2018
Daniela Dentico, David R. W. Bachhuber, Brady A. Riedner et al.
18 citations
Long-term meditators showed increased low- and fast-frequency brain oscillations during wakefulness after two 8-hour sessions of mindfulness or compassion-and-loving-kindness meditation, peaking at 8 and 15 Hz over prefrontal and left centro-parietal electrodes. These waking changes correlated with previously observed meditation-related increases in low-frequency NREM sleep EEG activity (4-12 Hz), particularly in the theta-alpha range. The findings suggest that sleep homeostatic response alone cannot explain the post-meditation sleep changes; instead, a reverberation of meditation-related processes during subsequent sleep may be involved. No differences emerged between meditation styles or in meditation-naïve participants.