Nav: Home

Anesthesia changes neuronal choreography

November 11, 2016

Establishing how the brain produces consciousness is one of the most challenging research questions in the field of neuroscience. In an effort to get closer to an answer, a team led by Dr. Mazahir T. Hasan, a researcher with Charité's NeuroCure Cluster of Excellence, joined forces with colleagues from the Max Planck Institute for Medical Research in Heidelberg. By visualizing neuronal activity in the brains of mice, they were able to compare how brain activity differs in conscious and anesthetized mice. NeuroCure's Dr. Hasan explains: "We used a fluorescent protein that converts electrical signals into light signals. This enabled us to visualize the frequency and average amplitude of neuronal responses, and allowed us to reveal the existence of neuronal synchrony." Results from this research would suggest that consciousness is not simply dependent on the number of active neurons inside the cortex; instead, it seems to be dependent upon the way these nerve cells communicate and on the degree to which they manage to differ in terms of their activity patterns.

The awake cortex showed complex activity patterns, with individual cells firing at different times. Under anesthesia, all neurons displayed identical activity patterns and fired at the same time. "While one might expect the brain to cease its activity under anesthesia, in reality, the situation is quite different. Neurons remain highly active but change their communication mode. During unconsciousness they become highly synchonized -- in simple terms all neurons start doing the same thing. " explains Mr. Thomas Lissek, a neurobiologist from Heidelberg and the study's first author. Another surprising finding was that neurons were more sensitive to environmental stimuli under anesthesia than when the brain was awake. "This is especially surprising, as anesthesia is used to block both pain and environmental stimuli during surgery," says Mr. Lissek. Some of the brain regions that are normally dedicated to tactile perception even responded to sound information.

These new insights into neuronal activity patterns provide information regarding the identity of the cellular parameters involved in producing consciousness and the loss of consciousness. Once combined with further advances that would allow us to measure neuronal activity inside the human brain, these findings could contribute to improving our diagnostic capabilities in conditions such as coma and locked-in syndrome. For the first time, this study succeeded in showing that it is possible to observe visually identifiable neuronal networks over a period of several weeks in order to study the after-effects of anesthesia. "It is clear that investigation of anesthesia will produce deep insights into the mechanism of consciousness", emphasizes Hasan.
-end-
*Thomas Lissek, Horst A. Obenhaus, Désirée A. W. Ditzel, Takeharu Nagai, Atsushi Miyawaki, Rolf Sprengel, and Mazahir T. Hasan. General Anesthetic Conditions Induce Network Synchrony and Disrupt Sensory Processing in the Cortex. Frontiers in Cellular Neuroscience. 2016; 10: 64. doi: 10.3389/fncel.2016.00064.

Charité - Universitätsmedizin Berlin

Related Neurons Articles:

How do we get so many different types of neurons in our brain?
SMU (Southern Methodist University) researchers have discovered another layer of complexity in gene expression, which could help explain how we're able to have so many billions of neurons in our brain.
These neurons affect how much you do, or don't, want to eat
University of Arizona researchers have identified a network of neurons that coordinate with other brain regions to influence eating behaviors.
Mood neurons mature during adolescence
Researchers have discovered a mysterious group of neurons in the amygdala -- a key center for emotional processing in the brain -- that stay in an immature, prenatal developmental state throughout childhood.
Astrocytes protect neurons from toxic buildup
Neurons off-load toxic by-products to astrocytes, which process and recycle them.
Connecting neurons in the brain
Leuven researchers uncover new mechanisms of brain development that determine when, where and how strongly distinct brain cells interconnect.
More Neurons News and Neurons Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...