Neural substrates of cognitive switching and inhibition in a face processing task

Abstract

a b s t r a c t a r t i c l e i n f oWe frequently need to change our current occupation, an operation requiring additional effortful cognitive demands. Switching from one task to another may involve two distinct processes: inhibition of the previously relevant task-set, and initiation of a new one. Here we tested whether these two processes are underpinned by separate neural substrates, and whether they differ depending on the nature of the task and the emotional content of stimuli. We used functional magnetic resonance imaging in healthy human volunteers who categorize emotional faces according to three different judgment rules (color, gender, or emotional expression). Our paradigm allowed us to separate neural activity associated with inhibition and switching based on the sequence of the tasks required on successive trials. We found that the bilateral medial superior parietal lobule and left intraparietal sulcus showed consistent activation during switching regardless of the task. On the other hand, no common region was activated (or suppressed) as a consequence of inhibition across all tasks. Rather, task-specific effects were observed in brain regions that were more activated when switching to a particular task but less activated after inhibition of the same task. In addition, compared to other conditions, the emotional task elicited a similar switching cost but lower inhibition cost, accompanied by selective decrease in the anterior cingulate cortex when returning to this task shortly after inhibiting it. These results demonstrate that switching relies on domain-general processes mediated by postero-medial parietal areas, engaged across all tasks, but also provide novel evidence that task inhibition produces domain-specific decreases as a function of particular task demands, with only the latter inhibition component being modulated by emotional information.

Neural substrates of rumination tendency in non-depressed individuals

“…The first frontal-dominant DMN map showed a negative correlation of RRS with ACC and PCC (both p < .001 uncorrected), whereas the second map also showed a selective negative correlation in PCC (but slightly weaker, at p = .005 uncorrected) and no effect in ACC. For the cognitive task, our whole-brain analysis focused on the main conditions of interest and correlations with RRS (more detailed results concerning all conditions are reported elsewhere; see Piguet et al, 2013). We first computed the main effect of condition by contrasting easy versus difficult trials.…”

“…Note that here we did not intend to compare switching performance between emotional and non-emotional tasks in our cognitive tasks, as this has been reported elsewhere (see Piguet et al, 2013) and this factor did not constitute an emotion induction procedure relevant to RRS (which is an individual trait dimension). Instead we primarily focused on (1) the tendency to ruminate in relation to attention load, and (2) the comparison of rumination activity at rest with the different attention load condition.…”

“…As an active cognitive condition, we used a task switching paradigm (Piguet et al, 2013) with emotional faces. On each trial, participants first saw a cue for 150 ms, either the word "emotion" or "color" or "gender", instructing them to judge the upcoming face pictures along this particular dimension.…”

“…There were 24 different faces taken from the Karolinska Directed Emotion Face database (Lundqvist, Flykt, & Ohman, 1998). Participants did 4 sessions of 216 trials each (see Piguet et al, 2013 for additional details on the task design).…”

Brain circuits implicated in psychogenic paralysis in conversion disorders and hypnosis

“…Both VMPFC and precuneus are implicated in representations of the self-including [63] autobiographical memory [82] and self-reflexive imagery [14]. VMPFC is particularly recruited in tasks requiring access to affectively relevant information about the self, including personal traits judgments [21,43,84], introspection on one's own feelings [44,46,52,69] and retrieval of emotional information from either past or prospective memory [20,91]. This region is also activated in response to incidental information related to the self without explicit task demands or conscious will [58].…”