The human brain appears to work by synchronous, long-distance linking of distant brain modules. Different groups of modules — different brain networks — are “in synch” at different times, depending upon the general types of tasks which the brain is performing. The brain networks of different people function somewhat differently — and even in the same person, brain networks can vary in efficiency and quality from hour to hour, or day to day.
Cognitive abilities, such as working memory, differ among people; however, individuals also vary in their own day-to-day cognitive performance. One potential source of cognitive variability may be fluctuations in the functional organization of neural systems. The degree to which the organization of these functional networks is optimized may relate to the effective cognitive functioning of the individual. Here we specifically examine how changes in the organization of large-scale networks measured via resting state functional connectivity MRI and graph theory track changes in working memory capacity.
… Common experience reminds us that on some days we do not feel as mentally astute as on others. A poor night’s sleep, illness, or stressful life events all may influence our cognitive faculties and lead to variability in performance on different days. _PLOSOne
When brains “go to sleep” — either naturally or under anesthesia — their brain networks begin to lose coherence, with different local brain modules unable to “synch up” or communicate effectively over a distance.
While conscious, different regions of the cortex fire at the same time, so neurons can communicate over long distances if necessary. [But under anesthesia] the peak of each slow wave represents a moment in which that area of the brain has gone silent – and all of its neurons stop firing. A silent region cannot receive a signal from a region that is awake, so out-of sync slow waves make long distance communication near impossible.
“It’s like different brain areas are in different time zones,” says Lewis, though in this case the time zones represent fractions of a second. “When one area is awake the other is asleep.” _NewScientist “Anaesthetised Brain”
Loss of coherence of brain networks during normal sleep is more complex, but similarly fascinating.
Even when awake, a person’s brain networks can switch on and off somewhat erratically, and function at varying degrees of efficiency and coherence — both in response to environmental cues and in response to natural internal rhythms and stresses.
In general, persons with better prefrontal executive function and higher intelligence are able to switch between brain networks more efficiently, to accomplish various tasks. Neurological and psychiatric disorders can impede efficiency of brain networks — and interfere with functional switching between brain networks, as can low IQ and poor executive function.
In the future, brain imaging is likely to become an integral part of practical psychiatry and clinical psychology. In fact, brain imaging will almost certainly become a routine part of childhood education and educational testing, once the technology can be made unobtrusive enough — perhaps as a “videogame controller.”
Most of us live according to predictable and habitual patterns, moving from “trance state” to “trance state,” seemingly as automatically as we might walk and communicate at the same time. These common trance states which often define our lives, are reflected on the neuronal level by shifts in brain network activity which could be monitored.
Being aware of one’s own brain activity can be very useful for the sake of changing unwanted behaviours, such as addictions or other dysfunctional habits of mind and body. This type of “neurofeedback” is already being used in therapy for a wide range of problems — as well as in brain machine interfaces for controlling complex machines or recreational videogames.
Besides feedback, another way of altering habitual brain networks might be through the use of electromagnetic stimulation of the brain, such as TMS or tDCS. By increasing or decreasing the level of excitability in specific parts of the brain, the function of neuronal networks across the entire brain can be influenced.
Selective brain stimulation in combination with feedback will likely become ordinary staples of routine mental health and development — in clinic, at home, and in schools — as the technology improves and the scientific foundations for such treatments are made more solid.
These tools are relatively safe, and available now — although methods and techniques are still being worked out. Those who try these things at home must assume the risk of self-experimentation. Unfortunately, it is taking an eternity for mainstream neuroscience to catch up to the avant-garde among clinicians and home experimenters.
And so one goes on from day to day, from one mood to another, one trance behaviour to another, in seemingly random fashion.
It is fine to be a “different person” at different times. But it is best to be an “appropriate person” for the particular time concerned. That isn’t always the case, with untrained and uninsightful minds.
Some home EEG devices you may find useful: