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Are brain-shifting apps and technology truly capable of shifting the brain into a “theta” state, which is said to help with relaxation, inward focus, and sleep? What exactly does it mean to change one’s “mental state” and is it even possible? For now, the evidence remains murky. But our understanding of the brain is growing exponentially as our methods of investigation improve.
Brain-measuring tech is evolving
Currently, no single approach to imaging or measuring brain activity gives us the whole picture. What we “see” in the brain depends on which tool we use to “look.” There are myriad ways to do this, but each one comes with trade-offs.
We learnt a lot about brain activity in the 1980s thanks to the advent of magnetic resonance imaging (MRI).
Eventually we invented “functional MRI,” which allows us to link brain activity with certain functions or behaviors in real time by measuring the brain’s use of oxygenated blood during a task.
We can also measure electrical activity using EEG (electroencephalography). This can accurately measure the timing of brain waves as they occur, but isn’t very accurate at identifying which specific areas of the brain they occur in.
Alternatively, we can measure the brain’s response to magnetic stimulation. This is very accurate in terms of area and timing, but only as long as it’s close to the surface.
What are brain states?
All of our simple and complex behaviors, as well as our cognition (thoughts) have a foundation in brain activity, or “neural activity.” Neurons—the brain’s nerve cells—communicate by a sequence of electrical impulses and chemical signals called “neurotransmitters.”
Neurons are very greedy for fuel from the blood and require a lot of support from companion cells. Hence, a lot of measurement of the site, amount and timing of brain activity is done via measuring electrical activity, neurotransmitter levels or blood flow.
We can consider this activity at three levels. The first is a single-cell level, wherein individual neurons communicate. But measurement at this level is difficult (laboratory-based) and provides a limited picture.
As such, we rely more on measurements done on a network level, where a series of neurons or networks are activated. Or, we measure whole-of-brain activity patterns which can incorporate one or more so-called “brain states.”
According to a recent definition, brain states are “recurring activity patterns distributed across the brain that emerge from physiological or cognitive processes.” These states are functionally relevant, which means they are related to behavior.
Brain states involve the synchronization of different brain regions, something that’s been most readily observed in animal models, usually rodents. Only now are we starting to see some evidence in human studies.
Various kinds of states
The most commonly-studied brain states in both rodents and humans are states of “arousal” and “resting.” You can picture these as various levels of alertness.
