In sleep, brain activity, specially in the default mode network (DMN) is reduced. For example, Amyloid beta production by neurons has a 70 % jump in wakefulness compared with sleep (Kress et al. 2018 J Exper Med). Can one assume that the same would happen in case of coma, or anaesthesia? Are they similar at all in terms of brain activity?
As I searched, it seems we are able to induce an artificial coma, like what we do for anaesthesia? If so, how long could it last at most?
The last but not least, have people taken effect systematic MRI during comma, anaesthesia, and sleep?
I thank you in advance for your help.
Hi.
Yes they are differ, there are difference in the state of the brain among coma, sleep, and anaesthesia.
I recomend to read this article, it exlain the differences very clear.
General Anesthesia, Sleep, and Coma
Emery N. Brown, M.D., Ph.D., Ralph Lydic, Ph.D., and Nicholas D. Schiff, M.D.Author
Amit
To the best of my knoledge, their is no EEG activity typical to REM in Coma and Anesthsia.
The article suggested by Amit Green, Brown et al. 2010, explains the differences well. The article partially answers my questions. I summarize here what I understood from this article.
The electroencephalographic (EEG) patterns are different in all three cases. Anesthesia is more closer to coma than to sleep in terms of EEGs and physical/behavioral symptoms of the patient. Rapid eye movement (REM) is only seen in sleep. The brain activity is significantly reduced in coma and anesthesia, similar (???) to non-REM sleep states. Reference 31 in the article, Alkire et al. 1995, also shows how the brain metabolism is reduced during anesthesia by using positron emission tomography (PET) technique. It seems the total brain activity is equivalent to sleep, if not lower, for both coma and anesthesia. Although the article differentiates the three cases well by comparing EEGs and physical/mental symptoms, detailed analysis of brain neural activity is still lacking. I suggest the article for those who want to know the general differences between these three brain states.
1. Coma is a state of profound unresponsiveness with variable EEG activity that depends on a brain injury. It can be metabolic or structural.
2. Anesthesia is a revesible drug-induced coma.
3. Sleep is a state of decreased arousal with two states REM and Non-REM. It can be physiological or pathological.
The EEG can show specific patterns of 1, 2 or 3. A cognitive dysfunction may be latent in all 3 states, especially in elderly patients.
WITHOUT GETTING INTO MUCH DETAIL IN THIS FORMAT, I WOULD SUGGEST LOOKING AT A NUMBER OF ADDITIONAL SOURCES INCLUDING BARGAMASCO'S WORK FORM THE '60'S. THERE IS A LARGE LITERATURE ON THE SUBJECT.
https://www.clinph-journal.com/article/0013-4694(68)90198-3/abstract
https://www.sciencedirect.com/science/article/pii/S1388245702002183
Alexandre, A., Rubini, L., Nertempi, P., & Farinello, C. (1979). Sleep alterations during post-traumatic coma as a possible predictor of cognitive defects. In Proceedings of the 6th European Congress of Neurosurgery (pp. 188-192). Springer, Vienna.
https://link.springer.com/chapter/10.1007/978-3-642-67605-5_64
Article General Anesthesia, Sleep, and Coma
The 10th International Symposium on Memory and Awareness in Anaesthesia (MAA10)has taken place in June 19th-21st, 2017 in Helsinki, Finland. Since 1989 an international group of investigators, monitor developers, and patients who have experienced intraoperative awareness have met every three years in Europe, North America or Asia.
At this last symposium there was lots of information regarding your question. The proceedings of this symposium have to my notice been published in the BMJ this year.
Yes there is a huge difference among these. I would suggest you to read about different stages of the general anesthesia. That will clarify your doubt to a large extent.
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