Research conducted by scientists at the Massachusetts Institute of Technology in Boston has shed light on the changes that occur in the brain due to fatigue. According to the team’s findings, the loss of concentration in individuals suffering from coincides with a surge of cerebrospinal fluid leaving the brain.
This process often hampers professional performance. For instance, during a business meeting, a sleep-deprived individual may find themselves unable to focus on a crucial issue right in the middle of the discussion. A typical outcome of such a “shutdown” is an accident caused by a drowsy driver.
And this is far from the only consequence of short-term lapses in attention, which is a common problem for those who regularly miss out on sleep. Scientists studied this phenomenon using electroencephalography (EEG) – a classic method for examining the bioelectrical activity of the brain. The team concluded that the attention deficits caused by are a significantly more critical condition than it may seem.
How Does the Brain React to Sleep Deprivation?
“When a person’s attention wanes, a wave of fluid begins to pulse in the brain. It’s not just that your neurons are ignoring the world; significant changes in the composition of the fluid in the brain are also taking place,” noted Dr. Laura Lewis, the lead author of the study.
The team involved 26 adult volunteers, as reported by The Guardian. Each participant underwent EEG scanning after a restful night of and after being completely deprived of it. The researchers not only tracked the electrical activity of the brain but also analyzed physiological changes.
In the second phase of the study, participants were asked to complete specialized tests that measured their reaction times to specific signals. Unsurprisingly, after sleep deprivation, the volunteers showed significantly poorer results: they reacted more slowly or didn’t respond at all.
Lapses in attention were accompanied by striking changes. Scans revealed a wave of cerebrospinal fluid that is rapidly expelled from the brain after a lapse in attention and returns approximately one second after attention is regained. Such waves are typically observed during deep sleep and are believed to help the brain eliminate metabolic waste that accumulates throughout the day.
The researchers also noted that the pupils of the participants constricted about 12 seconds before the fluid left the brain and then returned to normal. Breathing and heart rates also slowed down, the researchers reported in the journal Nature Neuroscience.
According to the team, these disruptions occur when the brain attempts to balance normal cognitive activity with essential functions it typically performs during sleep. Thus, the brain seeks to rest, the authors of the study believe.
Commenting on the work of her colleagues, neurobiologist Ria Kodosaki from University College London suggested that these changes are likely “structured biological events typically observed at the onset of sleep, and lapses in attention are not passive but organized to give the brain a brief rest.”
The scientist posited that, paradoxically, these dangerous lapses might be a way for the brain to protect itself. They serve as “forced pauses: the brain temporarily disconnects from the external world to carry out important housekeeping tasks.”
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