Silvina G. Horovitz1,2, Allen R. Braun3, Walter S. Carr4, Dante Picchioni5, Thomas J. Balkin5, Masaki Fukunaga2, Jeff H. Duyn2
1Human Motor Control Section - MNB, NINDS-NIH, Bethesda, MD, USA; 2Advanced MRI - LFMI, NINDS-NIH, Bethesda, MD, USA; 3Language Section Voice, Speech and Language Branch , NIDCD - NIH, Bethesda, MD, USA; 4MSC USN, Naval Medical Research Center, Silver Srping, MD, USA; 5Department of Behavioral Biology, Walter Reed Army Institute of Research, Silver Srping, MD, USA
The default-mode-network (DMN) is a collection of brain regions highly active in absence of overt behavior. Its function has been attributed to self-reflective thoughts, though it has also been observed in light-sleep and in anesthetized monkeys. Here, we studied the human DMN connectivity during deep sleep, a condition devoid of self-reflective thoughts and low conscious awareness. We show a decoupling of anterior and posterior portions of the DMN, suggesting that reduction of consciousness is reflected in altered levels of network coherence. The activity in each area remains unchanged suggesting it is not activity per-se but rather the coherent activation of the parts that lead to a conscious experience.