Cortical excitability changes in patients with sleep-wake disturbances after traumatic brain injury

Raffaele Nardone,  Jürgen Bergmann,  Alexander Kunz,  Francesca Caleri,  Martin Seidl,  Frediano Tezzon,  Franz Gerstenbrand,  Eugen Trinka,  Stefan Golaszewski. Cortical excitability changes in patients with sleep-wake disturbances after traumatic brain injury. Journal of Neurotrauma.  New York:Jul 2011.  Vol. 28,  Iss. 7,  p. 1165-1171

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I chose this article because I thought learning about the functioning of the brain during REM sleep would be an interesting topic to learn about. This article focuses on neural patterns in the brain in relation to rapid eye movement sleep phase. The study had seventeen participants that had normal or corrected – to- normal visual acuity, normal eye movements, and free of psychiatric / sleep disorders and medication. The participants had to stay awake night until the beginning of the experiment and they had sleep inside a MR scanner for two nights in a row. The participants who showed distinct REM sleep in the scanner were also selected to participate in a control experiment during which participants made self-paced saccades in total darkness. The results found that the experiment in which subjects made self-paced saccades in total darkness showed no activation in the visual cortex. The REM – related activation in the primary visual cortex without any input from the retina shows evidence for the existence of human potogeniculoccipital waves (PGO waves) . These results help find a link between REM sleep and dreaming. The time-course analysis of blood oxygenation level dependent responses in the study indicated that the activation of the pontine tegmentum, ventrposterior thalamus and primary visual cortex started before the occurrence of REMs. The researcher’s findings displayed that specific parts of the brain are activated during this stage sleep.