Experiments on humans and monkeys have discovered the rhythmic work of the area that controls attention: fluctuations in neuronal activity at a frequency of about four times per second make us distract each time.
As you read this sentence, your brain will try several times to be distracted by something else. New studies have shown the connection between the rapid rhythmic activity of brain neurons with switching attention. The frequency of these fluctuations is about four times per second: each time activity decreases, we take a quick look at the environment, looking for potentially interesting or dangerous changes that are important for survival.
Ian Fiebelkorn and colleagues at Princeton University conducted experiments on monkeys and human volunteers, patients with severe epilepsy and undergoing surgery for treatment. The activity of their neurons was recorded with high accuracy using electrodes embedded directly into the brain. Subjects sat in front of the screen and had to concentrate on a point in its center while a video camera monitored their eye movements.
Then subtle rectangular shapes flashed and died on the screen very quickly. Both humans and monkeys (who were previously trained) tried to determine whether these rectangles were oriented vertically or horizontally. If this succeeded, the macaques pulled the lever, and the people released the pressed mouse button. Scientists report the results of experiments in the journal Neuron.
The researchers' main interest has been in the workings of the Frontoparietal Network, which is known to control our attention. Precise electrodes found that neurons in this network, like neurons involved in visual processing, exhibit cyclical vibrational activity, forcing us to rhythmically distract from the task and make quick subconscious attempts to switch at a frequency of about four times per second.
Judging by the fact that the same rhythms are found in both humans and monkeys, this mechanism is quite ancient. The authors believe that people with attention deficit or hyperactivity disorder may experience a malfunction of this particular mechanism of coordinated “pulsation” of two groups of neurons.
Sergey Vasiliev