Shravani Khisti - Neuroscience Section Editor
Seeing our ‘life flash before our eyes’ is a common addendum to any adrenaline-spiked story about how one may have had a near encounter with death. The research paper, “Surge of Neurophysiological Coupling and Connectivity of Gamma Oscillations in the Dying Human Brain” explains the mechanism behind the phenomenon through four different case studies of comatose patients with previous cardiac arrests who were taken off of life support. Their study “challenges our fundamental understanding of the dying brain, which is widely believed to be non-functioning under such conditions” (Xu et al. 2023). Previously, scientists believed that the brain was actually less active in humans during cardiac arrests; however, animal models demonstrated a paradoxical surge in gamma oscillations or brain waves (the primary measure of activity in the brain).
The study states that survivors of clinical death have previously experienced “internal perception of bright light or familiar faces” which can explain how our dying brain still has the capability to internally generate visions without external stimuli. The region responsible for this is the posterior cortical zone or ‘hot zone’ which possibly also occupies areas responsible for crafting dreams. Out of the four patients, two experienced enhanced gamma wave oscillations while the other two had damaged autonomic nervous systems which could explain the differences in activity. "This recent discovery of heightened brain activity during death linked with hypoxia has been revolutionary to our understanding of brain function." It challenges the traditional assumption of brain hypoactivity, especially during cardiac arrest, and emphasizes the need for a reevaluation of the brain's role in this critical physiological state.
Reference:
Xu, G., Mihaylova, T., Li, D., Tian, F., Farrehi, P. M., Parent, J. M., Mashour, G. A., Wang, M. M., & Borjigin, J. (2023b). Surge of neurophysiological coupling and connectivity of gamma oscillations in the dying human brain. Proceedings of the National Academy of Sciences, 120(19). https://doi.org/10.1073/pnas.2216268120
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