Scientist brain also under anesthesia wide awake?

Nerve cells in the brain highly active during anesthesia
Although one might assume that the brain ceases to work during general anesthesia, researchers have now discovered that nerve cells in the cerebral cortex are highly active even during deep anesthesia. However, they change their working mode.

Nerve cells in the brain remain active
Scientists at Berlin's Charité University Hospital have been able to show in a study that nerve cells in the brain remain in action even during deep anesthesia, even though the consciousness is completely switched off. However, they change their working mode. As the researchers report in the journal "Frontiers in Cellular Neuroscience", the neurons work synchronously under anesthesia and react unexpectedly sensitive to environmental stimuli.

In fact, one could assume that the brain stops working during a general anesthetic. But scientists have now discovered that nerve cells in the cerebral cortex are also active during deep anesthesia. (Image: torwaiphoto / fotolia.com)

How consciousness is produced
According to a Charité note, scientists wanted to get closer to the answer to the question of how the brain produces consciousness. For this, a team has Mazahir T. Hasan from the Charité together with colleagues at the Max Planck Institute for Medical Research Heidelberg compared the brain activity of mice in the waking, conscious state and under anesthesia.

The respective activity of the nerve cells were visualized. Dr. Hasan explained, "We used a fluorescent protein that converts electrical signals into light signals. The number and the average amount of discharges as well as the synchronicity of the nerve cells in the network could thus be shown. "

Consciousness in the brain, according to the results, does not seem to depend simply on the number of active neurons in the cortex (cerebral cortex), but rather on the subtleties of how they communicate with each other and how they can contrast their behavior.

Brain changes the way work
While the neurons of the cortex in the waking state in complex patterns at different times light up, it can be observed under anesthesia that they are all simultaneously and equally active.

"Contrary to the plausible belief that the brain stops being anesthetized, it just changes the way it works. According to our study, the strength of the nerve cell load does not change, "says the first author of the study, Thomas Lissek, neurobiologist in Heidelberg.

Under anesthesia more sensitive than in the waking state
What is also unexpected is the observation that neurons respond more sensitively to environmental stimuli under anesthesia than when they are awake. "A surprising observation, since anesthesia is used in particular to reduce pain and environmental stimuli during surgery," Lissek said. According to the information, a brain region that is normally responsible for tactile information even began to respond to acoustic stimuli.

As stated in the communication, the new insights into neuronal activity patterns provide clues as to which cellular parameters are associated with consciousness and loss of consciousness. Together with further advances, they could improve diagnostics, for example in coma patients or patients with locked-in syndrome.

The current study demonstrates for the first time that it is possible to observe visually identifiable neuronal networks over a period of several weeks to further investigate the effects of anesthesia. "We expect anesthesiology research to bring deep insights to human consciousness," Dr. Hasan. (Ad)