Anterior prefrontal involvement in implicit contextual change detection

Stefan Pollmann

doi:10.3389/neuro.09.028.2009

Abstract

Anterior prefrontal cortex is usually associated with high level executive functions. Here, we show that the frontal pole, specifically left lateral frontopolar cortex, is involved in signaling change in implicitly learned spatial contexts, in the absence of conscious change detection. In a variant of the contextual cueing paradigm, participants first learned contingencies between distractor contexts and target locations implicitly. After learning, repeated distractor contexts were paired with new target locations. Left lateral frontopolar [Brodmann area (BA) 10] and superior frontal (BA9) cortices showed selective signal increase for this target location change in repeated displays in an event-related fMRI experiment, which was most pronounced in participants with high contextual facilitation before the change. The data support the view that left lateral frontopolar cortex is involved in signaling contextual change to posterior brain areas as a precondition for adaptive changes of attentional resource allocation. This signaling occurs in the absence of awareness of learned contingencies or contextual change.

Highlights

Prefrontal cortex is almost synonymous with executive function
FRONTOPOLAR INVOLVEMENT IN IMPLICIT CHANGE PROCESSING Based on these findings, we propose that frontopolar cortex may compare the current environment with similar environments in the past to signal changes to structures of the fronto-parietal attention network (Corbetta et al, 1998; Gitelman et al, 1999; Pollmann and von Cramon, 2000; Corbetta and Shulman, 2002), thereby enabling a reallocation of attentional resources which is optimal for the new situation
Our aim was to investigate the contribution of anterior prefrontal cortex to the implicit ‘detection’ of changes in implicitly learned stimulus contingencies in the service of optimal attention allocation

Summary

Introduction

Prefrontal cortex is almost synonymous with executive function. We have found left lateral frontopolar activation in visual singleton feature search tasks, in which highly salient ‘odd-one out’ targets were to be detected (Pollmann et al, 2000; Weidner et al, 2002). Behavioral (Müller et al, 1995; Found and Müller, 1996), neuroimaging (Pollmann et al, 2006) and electrophysiological (Gramann et al, 2007; Töllner et al, 2008) evidence supports the view that dimension changes in visual singleton search lead to a shift of attentional weight from the old to the new target-defining dimension. The evidence suggests that left lateral anterior prefrontal cortex supports shifts of attention between visual dimensions (see Rogers et al, 2000)

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