Neurochemical Correlates of Mind-Wandering and Meta-Awareness

Mind-wandering frequently occurs throughout daily life, diverting attention away from both goal-oriented behavior and internal mental operations. The experience of mind-wandering varies in both the degree to which an individual is aware of their attentional state (meta-awareness) and the extent of their intention to mind-wander. Prior research links mind-wandering with the brain's default mode network. However, the association between mind-wandering and the concentration of excitatory (glutamate) and inhibitory (GABA +) neurotransmitters has largely been unexplored. Here, in 46 (34 females and 12 males) human participants, we employed 7T magnetic resonance spectroscopy to explore associations between neurochemicals in the left prefrontal cortex (PFC), right intraparietal sulcus, and right primary motor cortex (M1) and subtypes of mind-wandering. Across three behavioral paradigms, we employed self-caught mind-wandering probes as a proxy measure for meta-aware mind-wandering and probe-caught to assess mind-wandering that occurs without meta-awareness. Results showed that mind-wandering associations with neurochemical concentrations varied by brain region, cognitive task, and the nature of mind-wandering. Specifically, self-caught mind-wandering during the two-back task and probe-caught mind-wandering during the finger-tapping random sequence generation task (FT-RSGT) were associated with neurochemical concentrations in the PFC. In addition, intentional mind-wandering was associated with GABA + in M1 for the two-back (probe-caught) and FT-RSGT (self-caught). Unintentional mind-wandering was as associated with E/I balance in the PFC for the FT-RSGT (probe-caught) and two-back (self-caught). These findings provide insights into the neurochemical basis of mind-wandering. The propensity to mind-wander, as well as meta-awareness and intentionality of mind-wandering, appears to depend on the demands of different tasks.