Neuroscientists have taken a step closer to understanding those moments when our thoughts seem to vanish into thin air, a phenomenon known as “mind blanking.” A study published in The Journal of Neuroscience reveals that when people report having no identifiable thoughts — mind blanking — there is a marked reduction in brain activity across several key regions. This intriguing discovery contributes to broader conversations about consciousness and our ability to report experiences.
The authors behind the new study sought to better understand a relatively understudied area of cognitive neuroscience: the phenomenon of mind blanking, where individuals find themselves unable to recount their immediate-past mental content. Unlike mental states with reportable content, such as daydreaming or engaging in a task, mind blanking represents a unique state of consciousness that lacked thorough neural characterization.
“In the past 10 years, I have researched human unconscious states where communication is restricted (post-comatose disorders),” said corresponding author Athena Demertzi, a tenured research associate of the Belgian Fund for Scientific Research and director of the Physiology of Cognition Lab at the University of Liège, Belgium.
“Mind blanking seems to be the perfect case of unconscious, yet reportable, moments during ongoing thinking. In that respect, mind blanking can be used to isolate the ‘pure’ neural correlates of thinking, can help us understand the mechanisms that are involved in ongoing thinking in general, and potentially provide side information about pathological cases where thinking gets blurry (e.g. dementia).”
Demertzi conducted the study along with first author Paradeisios Alexandros Boulakis, a PhD trainee and research fellow at the Physiology of Cognition Lab, and other colleagues at the University of Liège. The researchers utilized previously collected data from 36 healthy, right-handed participants, whose brain activity was recorded while they rested in an fMRI scanner with their eyes open. During these scanning sessions, participants were probed at random intervals, ranging from 30 to 60 seconds, with an auditory cue.
Upon hearing this cue, participants were asked to report their mental state just before the cue was given. They had several options to classify their mental content: absence of thought (mind blanking), perceptions (attentiveness to sensory stimuli), or thoughts (whether these were dependent on or independent of immediate environmental stimuli).
This experience-sampling approach allowed the team to capture a snapshot of the participants’ mental states in real-time, providing invaluable data on the nature of mind blanking as it spontaneously occurred.
From the original pool, data from 31 participants were analyzed after excluding those who did not report experiencing each mental state at least once. The fMRI analysis focused on identifying brain regions that showed significant changes in activity during mind blanking reports compared to other types of mental states.
The study’s findings highlighted a distinct pattern of widespread brain deactivation during instances of mind blanking. Specifically, significant reductions in brain activity were observed in the occipital, frontal, parietal, and thalamic regions — areas traditionally associated with processing sensory information and higher-order cognitive functions.
Notably, these deactivations were more pronounced than the brain activity observed during other mental states, indicating a distinct neural signature for mind blanking. This reduction in activity suggests a temporary disengagement of the brain’s cognitive and sensory processing faculties, providing a neurobiological basis for the subjective experience of having “no thoughts.”
Furthermore, the absence of significant activations in the prefrontal cortex, an area often linked to complex cognitive functions, underscores the passive nature of mind blanking as opposed to active thought suppression or engagement.
“Our study indicates that when people report mind blanking moments there is reduced brain activity across the whole brain,” Demertzi told PsyPost. “This was found when mind blanking was reported without inducing it (e.g. we did not ask people to ‘try to empty their minds’), so it indicates that these moments can happen by default during waking life. This is exciting because it indicates that our brains might not be ‘on’ all the time when we are awake.”
Despite its insights, the study has some limitations. For instance, the inherent design of fMRI experience-sampling studies might not capture the fleeting nature of mind-blanking accurately due to the method’s temporal resolution. Moreover, the imbalance in the frequency of different mental states reported could have impacted the statistical power of the study.
“The experiment used pre-defined mental categories that people had to choose and report at specific time points,” Demertzi explained. “This setup could have affected the frequency that mind blanking gets reported because we could not account for what could have been happening between the time points.”
“Also, the small number of mind blanking reports made the statistical comparisons with content-oriented categories difficult. Finally, the fMRI environment works at slower paces, compared to EEG for example. In that case, although we could answer the ‘where in the brain’ question well, the ‘when’ needs to be interpreted with caution.”
This investigation into mind blanking opens new avenues for understanding the complexity of human thought and consciousness. It not only differentiates spontaneous mind blanking from its induced counterpart but also invites further exploration into how our brains navigate the absence of thought.
“The long-term goal is to better comprehend the biological basis of mind blanking,” Demertzi told PsyPost. “If mind blanking is reported spontaneously during waking life, it is worth examining why this is the case. Why does the brain need to work like that and how can it affect the typical person if mind blanking gets reported too often or too little?”
The researchers are currently investigating whether episodes of mind blanking are rooted in our physiological state. In other words, they are exploring the idea that the condition of our body plays a significant role in the occurrence of mind blanking.
“The hypothesis we are testing is whether mind blanking incidents get reported more often when the general bodily arousal is at the extremes, i.e. too low (after sleep deprivation) or too high (after intense physical exercise),” Demertzi explained. “In support of Open Science practices, we have pre-registered this hypothesis and rationale before we collected the data. We are now on the way to having our findings reviewed by expert peers.”
“Finally, the research of mind blanking broadens what we consider conscious experience, and can be a powerful tool in examining how subjective experience appears to us,” she added.
The study, “Whole-Brain Deactivations Precede Uninduced Mind-Blanking Reports,” was authored by Paradeisios Alexandros Boulakis, Sepehr Mortaheb, Laurens van Calster, Steve Majerus, and Athena Demertzi.
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