One of the hallmarks of cognitive control is the ability to flexibly update attention and action when goals change. The prefrontal cortex has long been identified as important for such updating, but much remains to be understood about the anatomical and temporal mechanisms that support cognitive flexibility within prefrontal networks. In the current study, Jackson et al. (2024) build upon insights from recent transcranial magnetic stimulation (TMS) and neuroimaging studies to investigate the critical role of prefrontal cortex for updating goals and selecting behaviourally-relevant stimuli.

 

To measure updating, the authors deploy an attentional switching paradigm in which participants selectively attend to one feature of a novel object (colour or form) while ignoring the other feature. On each trial, a symbol (called a rule cue) indicates whether to attend to the colour (green or blue) or to the form (X or non-X) of the upcoming object. By mapping each stimulus response to a separate button press (two buttons for the two colours; two buttons for the two features), the authors can then categorise different types of behavioural errors – focusing especially on attending incorrectly to the task-irrelevant feature (rule error) vs. applying the correct rule but failing to correctly identify the task-relevant feature (stimulus error). If disruption of a specific cortical region causes a selective increase in one type of error, then this would indicate that the stimulated region is important for either rule processing or stimulus processing.

 

The proposal includes a number of key features that add depth and rigor to the investigation. First, to probe the anatomical specificity of cognitive control, the authors will contrast the effect of TMS delivered to different prefrontal regions that reside within different networks and may have divergent roles in cognitive control: the dorsolateral prefrontal cortex (dlPFC, part of the multiple-demand network) and dorsomedial prefrontal cortex (dmPFC, part of the default mode network). Moreover, unlike many previous TMS studies, the authors will use electric field modelling to normalise cortical stimulation strength between regions, enabling a more controlled anatomical comparison. Second, since the task involves responding to a rule cue and then selectively attending to a task-relevant feature, it is likely that a particular brain region could be selectively critical at a specific time – for instance, if dlPFC were important for rule processing then it should only be necessary shortly after (or around) presentation of the rule cue. To capture the temporal specificity of cortical involvement, the authors will apply a short burst of TMS at different times, beginning either +150ms after the cue or +700ms during stimulus processing. In a preliminary study, the authors used magnetoencephalography (MEG) in combination with the same behavioural task and multivariate pattern analysis (MVPA) to identify these epochs for TMS. Finally, the experiment includes a range of additional control conditions and quality checks to rule out alternative explanations of potential findings, such as TMS impairing perception of the rule cue rather than implementation of the rule, and the effect of peripheral TMS artefacts. Overall, the study promises to reveal a range of intriguing new insights into the timecourse and anatomical specificity of cognitive updating, with implications for theories of prefrontal cortical function.

 

The Stage 1 manuscript was evaluated over one round of in-depth review. Based on detailed responses to the reviewers' and recommender’s comments, the recommender judged that the manuscript met the Stage 1 criteria and therefore awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/7pxjz (under temporary private embargo)

 

Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.

 
List of eligible PCI RR-friendly journals:

 

 

 

Jackon, J. B, Runhao, L., & Woolgar, A. (2024). Causal dynamics of task-relevant rule and stimulus processing in prefrontal cortex. In principle acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/7pxjz