Turku, Finland- Where does our brain go when we fall asleep? The super network at the center of the brain can help solve one of the biggest scientific problems-how does human consciousness work? Scientists in Finland have discovered a central core network filled with the same activities, whether a person sleeps normally or loses consciousness due to anesthesia.
Researchers from the University of Turku conducted two experiments, which revealed for the first time the natural mechanism behind human consciousness and its connection with people’s responses to sleep. One study examined the brain activity of people receiving drug anaesthesia, while another study looked at the reactions of subjects after natural sleep and waking.
In addition to using brain imaging techniques, the researchers also asked participants a series of questions when they woke up. These topics include whether volunteers are aware of their surroundings or whether they remember their dreams.
“A major challenge is to design a setup in which brain data in different states differ only in consciousness. Our research overcomes many previous confounding factors, and for the first time revealed the neural mechanism behind connecting consciousness.”
Unconscious has many forms
Researchers say that natural sleep and experimental anesthesia are powerful tools for studying human consciousness. In previous studies, scientists were confused about the state of awakening and the assumed unconscious state. Whether a person is conscious or not is usually determined by their behavior. For example, some people may think that people who lack meaningful responses are unconscious. However, studies have shown that slow response does not necessarily mean that a person is not aware of the surrounding environment, nor does it necessarily mean that it is unconscious.
A person who is unresponsive may still be aware of their surroundings, which means they are still “keep in touch”, while another person may not be aware of it, but still experiencing their inner world and “isolated”.
In this new study, scientists hope to identify the “specific state patterns” of brain activity by observing the “connected” and “disconnected” states of consciousness. They also aim to find the overall effect of anesthesia and sleep by comparing different doses of drugs and different sleep stages.
“This unique experimental design is the key idea of our research, allowing us to distinguish specific changes in the state of consciousness from the overall effect of anesthesia,” explained the first study and anesthesiologist Annalotta Scheinin.
Which parts of the brain make up the super network?
Researchers look for networks related to human consciousness in the brain. They do this by measuring the brain activity of adult men who fall asleep and undergo anesthesia via PET scans. This is an imaging test that allows the doctor to see how your brain is working.
The researchers awakened the patients in the middle of the experiment to interview them and confirm their contact status or their knowledge of their surroundings. They found that changes in connectivity are related to the key networks that connect multiple regions deep in the brain.
These areas include the thalamus (which shares motor and sensory signals with the rest of the brain), the cingulate cortex (emotion formation and processing), and the angular gyrus (spatial cognition, memory retrieval, and attention).
Rewrite common beliefs
The study found that when a volunteer lost contact, blood flow in these areas decreased, and when they regained consciousness, blood flow in these areas increased. Both sleep and anesthesia are in this case, indicating that this change corresponds to connectivity, not to sleep or medication.
“General anesthesia seems to be more like normal sleep than regular sleep. However, this explanation is very consistent with our recent electrophysiological results in another anesthesia study.” Harry Scheinin said.
Since the delay between wake-up and interview is minimal, the current results greatly increase our understanding of the nature of anesthesia. According to a common belief, successful general anesthesia does not require complete loss of consciousness, because it is enough to separate the patient’s experience from what is happening in the operating room,” Annalota Scheinin explained.
Research results are published in journals Journal of Neurology.
SWNS writer Laura Sharman contributed to this report.