SYDNEY, April 25 (Xinhua) -- A new study by Australian and European neuroscientists and philosophers revealed what's happening in the brain when minds go blank, a common yet poorly understood mental state.

The team analyzed 80 studies and concluded that mind blanking is a distinct experience, separate from "mind wandering," and occurs in about 5 to 20 percent of the waking life, according to the researchers from Australia's Monash University, Belgium's University of Liege and France's Paris Brain Institute.

The study, published on Thursday in the Cell Press journal Trends in Cognitive Sciences, defined mind blanking as the absence of reportable thoughts and it is often linked to sluggishness, drowsiness, or lapses in attention.

Mind blanking tends to occur during monotonous tasks, after sleep deprivation or intense physical activity, and can be more frequent in individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) or certain clinical conditions such as anxiety disorders, brain injuries, and sleep disorders, it said.

Brain scans revealed that before a mind blank, specific patterns appear in the frontal, temporal, and visual brain regions. The study found that during the blanking state, especially after attention-demanding tasks, heart rates and pupil sizes drop, brain activity becomes less complex, and brainwaves resemble those seen in sleep.

In some cases, the brain enters what researchers describe as "local sleep," where certain areas briefly shut down while the person remains awake, it said.

Both high-speed thinking and deliberate efforts to "empty the mind" can trigger blanking. These lead to deactivations in brain regions tied to memory, speech, and motor control, including Broca's area and the hippocampus, according to the study.

The researchers called for mind blanking to be recognized as a unique mental state, which could enhance the understanding of consciousness and attention. ■