Our brain is like a large concert hall. In order to direct and manage numerous and complex cognitive processes, it is necessary for several groups of neurons to activate and, like the different members of a musical orchestra, work in harmony to produce a symphony of processes that allow us to perceive and interact with our environment.
But just like orchestras, the brain may need a conductor to keep all its parts active and in sync. In this sense, several neuroscientists maintain that gamma rhythms, brain waves that fluctuate at a frequency of approximately 40 cycles per second, could play this role.
It is believed that These oscillations of gamma waves would act as a kind of clock or metronome that coordinates the transfer of information from one group of neurons to another, so there seems to be ample evidence to suggest that the role of gamma waves in cognitive processing is fundamental.
During decades of research in humans and other animals, patterns have been found in many areas of the brain that have been associated with a variety of cognitive processes, such as attention or working memory. Some studies have even linked alterations in these gamma oscillations to various neurological diseases, including Alzheimer’s disease and schizophrenia.
However, there seems to be no absolute consensus. Some neuroscientists believe that the role that gamma waves would play would not be so decisive, and they assure that these rhythms could correlate with brain activity, but not provide a significant contribution to it.
Metronome neurons: studies in mice
To investigate whether gamma waves really played an important role in coordinating neural activity, Neuroscientists Moore and Shin from Brown University began their study in mice discovering that a previously unknown set of neurons would be acting as a metronome.
These newly discovered cells fired rhythmically at gamma frequencies (30-55 cycles per second), regardless of what was happening in the outside environment, and the probability that an animal would detect a sensory stimulus was associated with the ability of these neurons to handle time.
Moore and Shin began their research as a general search for brain activity related to touch perception. And to do so, they implanted electrodes in a specific area of the mouse’s somatosensory cortex, responsible for processing sensory inputs. They then measured neural activity while observing the rodents’ ability to notice subtle taps on their whiskers.
The researchers focused on gamma oscillations and decided to analyze a specific group of brain cells, called fast-accelerating interneurons, because previous studies had suggested that they could participate in the generation of these fast rhythms. The analysis revealed that, as expected, the degree to which these cells fired at gamma frequencies predicted how well the mice would be able to detect contact with their whiskers.
But when neuroscientists delved deeper into the study, they found something strange. They expected that cells that would activate in response to a sensory stimulus would show the strongest links to perceptual accuracy. However, when examining the cells, this link had weakened. Then, they realized that perhaps the cells are not sensory and act as timekeepers, regardless of what is happening in the environment.
By repeating the analysis with only the cells that did not respond to the sensory stimulus, the link with perceptual accuracy became stronger. In addition to being unperturbed by the outside environment, this specific subset of neurons tended to spike regularly in gamma range intervals, like a metronome. It’s more, The more rhythmic the cells were, the better the animals seemed at detecting whisker taps What seemed to be happening, continuing with the initial metaphor of the concert hall, is that the better the conductor is at managing time, the better the orchestra will do.
The clocks of the brain
We have all heard of the internal clock or the biological clock. And it is that Our brain responds to the passage of time through physiological systems that allow us to live in harmony with the rhythms of nature, such as the cycles of day and night, or the seasons.
The human brain uses two “clocks.” The first, our internal clock, which allows us to detect the passage of time and is essential to function in our daily lives. With this watch we can, for example, measure the time elapsed between two activities, know how much time we have spent performing a task such as driving or studying, since otherwise these types of tasks would last indefinitely without us having any idea of the time that has elapsed. has passed.
The second clock could not only function parallel to the first, but would also compete with it. This brain system would be housed within the first clock, and would work in collaboration with the cerebral cortex to integrate temporal information This mechanism would be executed, for example, in moments when our body pays attention to how time has passed.
The feeling of being aware of the time that has passed is as necessary as maintaining a memory of what we have done during the process. And this is where a brain structure such as the hippocampus comes into play, responsible for processes such as inhibition, long-term memory or space, in addition to playing a fundamental role in remembering the passage of time, according to the latest scientific studies.
In the future, it will be essential to continue developing new treatments and investigating the relationship between these brain structures and our internal clocks with neurodegenerative diseases such as Alzheimer’s and other types of dementia, as well as with mental disorders and brain diseases in which brain degeneration processes are involved. notion of time and body space.
