A similar inhibitory function also has been suggested for delta band activity, which may suppress networks that are not essential for task accomplishment ( Harmony, 2013). Alpha-band oscillations are the dominant band in the human brain, important for information processing, especially in the visual cortex, and are likely to have an inhibitory function on cortical areas that are not in use ( Klimesch, 2012). Particularly, enhanced thalamocortical activity, increase of gamma power and long-range gamma synchronization (> 35Hz) has been identified in conscious perception ( Llinás et al., 1998 Tononi et al., 1998 Rodriguez et al., 1999 Singer, 2001 Varela et al., 2001). In healthy subjects, neural oscillations provide a temporal frame for information processing of perception, consciousness and memory during waking, dreaming and meditation ( Llinás and Paré, 1991 Llinas and Ribary, 1993 Llinás et al., 1998 Lutz et al., 2004 Beauregard and Paquette, 2008 Fries, 2009). It is hypothesized that the brain may generate a memory replay within this “unconscious” phase with an increase in oscillatory activity ( Mobbs and Watt, 2011 Facco and Agrillo, 2012 Greyson et al., 2012 Borjigin et al., 2013). The neurophysiological signature of this phenomenon is unclear. Subjective descriptions of this phenomenon are described as intense and surreal and include a panoramic life review with memory recalls, transcendental and out-of-body experiences with dreaming, hallucinations and a meditative state ( Vanhaudenhuyse et al., 2007).

Near-death experience (NDE) has been reported in situations where the brain transitions toward death. Albeit the influence of neuronal injury and swelling, our data provide the first evidence from the dying human brain in a non-experimental, real-life acute care clinical setting and advocate that the human brain may possess the capability to generate coordinated activity during the near-death period. The strongest coupling is observed for narrow- and broad-band gamma activity by the alpha waves during left-sided suppression and after cardiac arrest. Cross-frequency coupling revealed modulation of left-hemispheric gamma activity by alpha and theta rhythms across all windows, even after cessation of cerebral blood flow. After cardiac arrest, delta, beta, alpha and gamma power were decreased but a higher percentage of relative gamma power was observed when compared to the interictal interval. An increase of absolute power in gamma activity in the narrow and broad bands and a decrease in theta power is seen after suppression of bilateral hemispheric responses. Here, we present continuous electroencephalography (EEG) recording from a dying human brain, obtained from an 87-year-old patient undergoing cardiac arrest after traumatic subdural hematoma. No study has yet investigated this matter in humans.

Although a hypoactive state of brain activity has been assumed, experimental animal studies have shown increased activity after cardiac arrest, particularly in the gamma-band, resulting from hypercapnia prior to and cessation of cerebral blood flow after cardiac arrest. The neurophysiological footprint of brain activity after cardiac arrest and during near-death experience (NDE) is not well understood.

7Department of Neurosurgery, School of Medicine, University of Louisville, Louisville, KY, United States.

6Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, United States.

5Epilepsy Program, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.

4Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University of Toronto, Toronto, ON, Canada.

3Division of Neurosurgery, Department of Surgery, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.2Institute of Computer Science, University of Tartu, Tartu, Estonia.1Department of Neurosurgery, Henan Provincial People’s Hospital, Henan University People’s Hospital, Henan University School of Medicine, Zhengzhou, China.Raul Vicente 1,2†, Michael Rizzuto 3†, Can Sarica 4, Kazuaki Yamamoto 4, Mohammed Sadr 3, Tarun Khajuria 2, Mostafa Fatehi 3, Farzad Moien-Afshari 5, Charles S.

Cardiac coherence brainn injury