Clinical EEG and Neuroscience
January 1, 2014
Simone Sarasso, Mario Rosanova, Adenauer G. Casali et al.
164 citations
Consciousness requires both functional integration and differentiation in the brain, a property termed brain complexity. Transcranial Magnetic Stimulation combined with electroencephalography (TMS/EEG) can quantify this complexity. Studies consistently show that the complexity of the cortical response to TMS collapses during loss of consciousness in deep sleep, anesthesia, and vegetative state after severe brain injury. Complexity recovers when consciousness returns during wakefulness, dreaming, the minimally conscious state, or locked-in syndrome. This approach may help understand the pathophysiology of disorders of consciousness and requires careful methodological attention.
Clinical EEG and Neuroscience
March 1, 2023
Gloria M A S Tedrus, Letícia M Vargas, Karen G Rodrigues
People with epilepsy who have more frequent seizures report fewer daily spiritual experiences than those with better-controlled seizures. Right-hemisphere epileptiform activity is associated with more frequent spiritual experiences compared with left-hemisphere activity. Demographic factors such as age and education also correlate with spiritual experiences. The findings suggest a neurobiological link between epilepsy and spirituality.
Clinical EEG and Neuroscience
March 1, 2023
Alexander T. Duda, Adam R. Clarke, Frances M. De Blasio et al.
Novice meditators who practiced daily concentrative meditation for about a month showed changes in specific brain wave components during both meditation and resting states. Using frequency Principal Components Analysis (f-PCA), four spectral components were identified: Delta-Theta-Alpha, Low Alpha, High Alpha, and Alpha-Beta. All four components increased during meditation at the second session, but only Low Alpha (around 9.5-10.0 Hz) showed similar increases during resting. The findings support f-PCA as a novel method for analyzing psychophysiological states in meditation research.
Clinical EEG and Neuroscience
November 25, 2022
Shariful A. Syed, Ashley M. Schnakenberg Martin, J. Cortes-Briones et al.
Disruptions in neural oscillations, particularly in the gamma and theta frequency ranges, are a key mechanism by which THC, the primary psychoactive component of cannabis, perturbs brain function. Clinical EEG studies show that both chronic and acute cannabinoid exposure disrupts these neural oscillations in humans. The authors propose a hypothetical framework where endocannabinoids modulate neural synchrony at the network level, altering the fine tuning of oscillations and the inhibitory/excitatory balance of neural circuits. These oscillatory disruptions may relate to cannabis-induced changes in sensation, perception, and cognition, with implications for disorders such as schizophrenia.
Clinical EEG and Neuroscience
May 1, 2019
Shirley Telles, Deepeshwar Singh, K. V. Naveen et al.
Meditative focusing increased sympathetic arousal, as shown by higher low-frequency heart rate variability (HRV), lower high-frequency HRV, and a faster average heart rate. Defocused meditation decreased average heart rate. Both forms of meditation improved attention, measured by increased P300 brain-wave amplitude; defocused meditation also reduced P300 latency, meaning participants responded faster to an auditory oddball task. The findings indicate that meditation's effects on attention and sympathetic activity depend on the type of meditation practiced.
Clinical EEG and Neuroscience
October 1, 2015
Shirley Telles, Singh Deepeshwar, Kalkuni Visweswaraiah Naveen et al.
Meditation shortens the time it takes for the brain to process sounds in the auditory association cortex, as measured by a faster P2 component of long latency auditory evoked potentials. In contrast, random thinking and nonmeditative focusing reduce the number of neurons recruited in the secondary auditory cortex, auditory association cortex, and anterior cingulate cortex, shown by smaller peak amplitudes of P1, P2, and N2 components. The study assessed 60 male participants aged 18–31 years across four mental states based on traditional texts.
Clinical EEG and Neuroscience
January 1, 2013
Petr Bob, Elizabeth M. Zimmerman, Elizabeth A. Hamilton et al.
Conscious attention depends on large-scale information integration across brain regions and hemispheres, with the level of information transference influencing attentional capacity and being linked to emotional arousal and autonomic responses. A hypothesis that changes in conscious attention during meditation could be reflected in autonomic activity via left–right information transference was tested by measuring bilateral electrodermal activity in 7 healthy persons during resting state, a Stroop task, a neurofeedback memory test, and meditation. Pointwise transinformation (PTI) distinguished these attentional states, with the highest level occurring during meditation, indicating greater left–right connectivity. Other measures like mean skin conductance level or laterality index did not differentiate the states. PTI may be useful for assessing information flow related to neural functioning, potentially reflecting integrative autonomic changes during focused attention.
Clinical EEG and Neuroscience
April 1, 2012
Shirley Telles, Bhat Ramachandra Raghavendra, Kalkuni Visweswaraiah Naveen et al.
Meditation, as described in traditional yoga texts, delays auditory information transmission at the level of the medial geniculate and primary auditory cortex. In 60 participants, the Na and Pa components of mid-latency auditory evoked potentials showed prolonged latencies during meditation compared to random thinking, nonmeditative-focused thinking, and meditative focusing. Meditative focusing did not produce this effect. The findings suggest that meditation, but not mere focused attention, alters early sensory processing.