Mind-blanking (MB) is the inability to report mental contents, challenging the view of a constantly thought-oriented mind during wakefulness. Using fMRI experience-sampling we show that MB is reported scarcely, fast, and has low transitional dynamics, pointing to its role as a transient mental relay. MB's cerebral profile is linked to an overall positive connectivity pattern, bearing great resemblance to neural configurations observed in local sleeps, possibly reflecting neuronal silencing during wakefulness. We also find less efficient information flow between the default mode (DMN) and other networks before reporting MB. The DMN-salience network segregation was further able to classify MB from other reports in fewer steps, suggestive of an early saliency evaluation of contentless phenomenology along the neurocognitive hierarchy. Collectively, MB's unique neurofunctional profile among thought-oriented reports supports the view of instantaneous mental absences happening during wakefuless, paving the way for more mechanistic investigations of this particular phenomenology during ongoing mentation.