While you’re at work, imagine: when you suddenly start wandering your mind for weekend thoughts, until you catch your boss walking out of the corner of your eye.
This occurs naturally and automatically in consciousness, back and forth and is the result of two brain conditions: the dorsal attention network (DAT), which corresponds to our awareness of the environment around us and the default-mode network (DMN) Have, which corresponds with it. Focus on yourself.
Brain researchers consider these states to be conflicting, meaning that when one is activated, the other is suppressed. Michigan medicine researchers studying consciousness have provided evidence of this phenomenon using fMRI and illustration, using a unique method, the ever-changing nature of the brain, even of anesthesia or otherwise unresponsive. Under.
Scientists have hypothesized that DAT and DMN are functions associated with higher-order brain consciousness and are suppressed during subliminal states. But studies in these states have relied on methods that are unable to show definitively that they are correlated.
The research team led by Jirui Huang, Ph.D. A research investigator from the U-M Department of Anesthesiology used general anesthetic drugs to see what happens to both of these important brain networks.
“We wanted which networks belong to consciousness,” Huang says. “By suppressing consciousness, we developed a better understanding of which networks are important to consciousness by the process of elimination.”
Most previous studies on these networks have relied on fMRI data on average over several minutes.
“But we know that the brain is changing from second to second with different networks engaged in collaboration,” says Anthony Hudetz, DMB, PhD, professor of anesthesiology and director of the Center for Consciousness Science and a senior author on the paper . ”
Temporal can remember the actual dynamics of the average brain and whatever the brain does reflects everything from our thinking to our imagination.”
The study team’s approach, which was taken by second images of brain activity, avoids the controversial processing technique called a global contention regression, which is used to reduce noise from fMRI data in most other studies of this type.
For their study, the team compared 98 participants who were awake, lightly sedated or typically with anesthesia as well as patients with brain disorders of consciousness to analyze activity patterns in their brains from the other.
Using machine learning, they revealed eight primary functional networks of brain activity: the aforementioned DAT and DMN, the frontier network (involved in high-level processing), the sensory and motor networks (involved in sensation and movement), the visual network (vision). Included in), ventral attention networks (related to attentional stimuli), and global networks of activation and deactivation (whole brain activity).
The team showed that the brain very quickly transitions from one network to another in a regular pattern. Transition trajectories constitute an ‘temporal circuit’, where the conscious brain dynamically cycles through structured patterns over time.
In patients with sedation and in patients with brain disorders, infections for DAT and DMN, higher-order brain functioning was significantly reduced. They also found that the pattern of transition between networks depended on how unconscious the subject was.
“For example, under ketamine, in addition to visual and abdominal attention networks, there has been an increase in the number of infections in the global activation and deactivation network, which is related to psychiatric symptoms such as hallucinations,” Huang says.
Most importantly, however, correlated DATs and DMNs were essentially isolated from the network’s temporal circuits, when patients were inattentive (and possibly unconscious) regardless of the path they were exposed to (drugs or injuries. ) Was found.
Huang expects the next detection of how the brain controls these moment-to-moment changes from one moment to another.
The ongoing stream of human consciousness relies on two different cortical systems, the default mode network and the dorsal attention network, which alternate their activity in an alternative way.
We investigated how the two systems in the conscious brain are regulated and how they are disrupted when consciousness is reduced. We provide evidence for a “temporal circuit” characterized by a set of adjectives with which dynamic brain activity occurs.