The Decoupled Mind: Mind-wandering Disrupts Cortical Phase-locking to Perceptual Events

Abstract

Abstract■ The mind flows in a "stream of consciousness," which often neglects immediate sensory input in favor of focusing on intrinsic, self-generated thoughts or images. Although considerable research has documented the disruptive influences of taskunrelated thought for perceptual processing and task performance, the brain dynamics associated with these phenomena are not well understood. Here we investigate the possibility, suggested by several convergent lines of research, that taskunrelated thought is associated with a reduction in the trial-totrial phase consistency of the oscillatory neural signal in response to perceptual input. Using an experience sampling paradigm coupled with continuous high-density electroencephalography, we observed that task-unrelated thought was associated with a reduction of the P1 ERP, replicating prior observations that mind-wandering is accompanied by a reduction of the brainevoked response to sensory input. Time-frequency analysis of the oscillatory neural response revealed a decrease in theta-band cortical phase-locking, which peaked over parietal scalp regions. Furthermore, we observed that task-unrelated thought impacted the oscillatory mode of the brain during the initiation of a task-relevant action, such that more cortical processing was required to meet task demands. Together, these findings document that the attenuation of perceptual processing that occurs during task-unrelated thought is associated with a reduction in the temporal fidelity with which the brain responds to a stimulus and suggest that increased neural processing may be required to recouple attention to a task. More generally, these data provide novel confirmatory evidence for the mechanisms through which attentional states facilitate the neural processing of sensory input. ■

Lateral prefrontal cortex lesion impairs regulation of internally and externally directed attention

“…More broadly, there is clear evidence implicating frontocentral midline theta power in cognitive control (Cavanagh et al, 2009; Cavanagh and Frank, 2014). The robust attenuation of theta power during internally vs. externally directed attention in our data is also in line with reports of disrupted theta phase-locking during an off-task state in which subjects’ attention is directed away from an ongoing visual target detection task (Baird et al, 2014). Together, these findings indicate frontocentral midline theta serves as an electrophysiological marker of externally directed attention in the current task.…”

Maintenance and Representation of Mind Wandering during Resting-State fMRI

“…Previous support for the decoupling hypothesis primarily comes from electroencephalography (EEG) studies during cognitive tasks373839. In these EEG studies, task-related attention during cognitive activity was characterized by amplitude of event-related potentials (ERPs)3738 and phase-locking consistency across task trials39.…”

“…Previous support for the decoupling hypothesis primarily comes from electroencephalography (EEG) studies during cognitive tasks373839. In these EEG studies, task-related attention during cognitive activity was characterized by amplitude of event-related potentials (ERPs)3738 and phase-locking consistency across task trials39. The amplitude of ERPs was reduced for participants who engaged in greater amounts of task-unrelated thought3738, and task-unrelated thought was associated with a reduction in the trial-to-trial phase-locking consistency to visual events39.…”

Decreasing propensity to mind-wander with transcranial direct current stimulation

“…Mind wandering is related to adaptive functions such as planning, creativity, and a coherent sense of self (Andrews-Hanna, Smallwood, and Spreng 2014). However, mind wandering, also referred to as task-unrelated thoughts (TUTs), causes intermittent shifts of attention from the task at hand and dampens sensory information processing (Baird et al 2014; Barron et al 2011), resulting in poor task performance (Kam, Dao, and Stanciulescu 2013;Kane and McVay 2012), accidents (He et al 2011), and maladaptation (e.g., poor lesson comprehension; Smallwood, Fishman, and Schooler 2007). Thus, regulating mind wandering propensity is quite important.…”