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Multi-modal representation of effector modality in frontal cortex during rule switching.

Hodgson TL, Parris BA, Benattayallah A, Summers IR - Front Hum Neurosci (2015)

Bottom Line: Participants performed a rule switching task using different effector modalities.Multivariate analysis revealed that the pattern of activity evoked by Flip rule Feedbacks within an apparently supra modal frontal region (dorsolateral frontal cortex) discriminated between response epochs.The results are consistent with the existence of multi-modal representations of stimulus-response (SR) rules within the frontal cerebral cortex.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Lincoln Lincoln, UK.

ABSTRACT
We report a functional magnetic resonance imaging (fMRI) study which investigated whether brain areas involved in updating task rules within the frontal lobe of the cerebral cortex show activity related to the modality of motor response used in the task. Participants performed a rule switching task using different effector modalities. In some blocks participants responded with left/right button presses, whilst in other blocks left/right saccades were required. The color of a Cue event instructed a left or right response based upon a rule, followed by a Feedback which indicated whether the rule was to stay the same or "Flip" on the next trial. The findings revealed variation in the locus of activity within the ventrolateral frontal cortex dependent upon effector modality. Other frontal areas showed no significant difference in activity between response epochs but changed their pattern of connectivity with posterior cortical areas dependent upon response. Multivariate analysis revealed that the pattern of activity evoked by Flip rule Feedbacks within an apparently supra modal frontal region (dorsolateral frontal cortex) discriminated between response epochs. The results are consistent with the existence of multi-modal representations of stimulus-response (SR) rules within the frontal cerebral cortex.

No MeSH data available.


Schematic of rule switching task. Participants switch between two rules linking a centrally presented colored Cue with a motor response to the left or right. The participant either holds or reverses the rule linking cue and response on the next trial based on the Feedback event following response execution (“Hold”/“Flip”). Each participant completed four blocks, two blocks each for which either Manual press button responses (“Hand epochs”) or saccades were made to the left or right (“Eye epochs”).
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Figure 1: Schematic of rule switching task. Participants switch between two rules linking a centrally presented colored Cue with a motor response to the left or right. The participant either holds or reverses the rule linking cue and response on the next trial based on the Feedback event following response execution (“Hold”/“Flip”). Each participant completed four blocks, two blocks each for which either Manual press button responses (“Hand epochs”) or saccades were made to the left or right (“Eye epochs”).

Mentions: A schematic of the task is shown in Figure 1. Each trial in the task began with the presentation of a blue or yellow colored circle (the response contingent Cue event). Subjects made a left or right behavioral response dependent upon the color of the cue and the current rule linking color with direction. For “Eye” (saccade) blocks participants were instructed to fixate one of two peripheral response locations (marked by two onscreen response boxes located approximately five degrees to the left or right of the central location and displayed during Eye epochs only). When the cue stimulus was extinguished they then had to make a return saccade to fixate the central location. The word “hold” or “flip” was then presented at fixation to indicate to the participant whether to hold or reverse the current rule on the following trial (Feedback event). In order to resolve the fMRI response to these discrete events within a trial i.e., Cue and Feedback, the period between each event and trial was varied randomly between 2200, 4400 and 10200 ms such that inter-event intervals did not correspond to multiples of the TR period. Varying the period between individual events in this manner within as well as between trials ensures that discrete events can be resolved within a trial (Parris et al., 2007).


Multi-modal representation of effector modality in frontal cortex during rule switching.

Hodgson TL, Parris BA, Benattayallah A, Summers IR - Front Hum Neurosci (2015)

Schematic of rule switching task. Participants switch between two rules linking a centrally presented colored Cue with a motor response to the left or right. The participant either holds or reverses the rule linking cue and response on the next trial based on the Feedback event following response execution (“Hold”/“Flip”). Each participant completed four blocks, two blocks each for which either Manual press button responses (“Hand epochs”) or saccades were made to the left or right (“Eye epochs”).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585120&req=5

Figure 1: Schematic of rule switching task. Participants switch between two rules linking a centrally presented colored Cue with a motor response to the left or right. The participant either holds or reverses the rule linking cue and response on the next trial based on the Feedback event following response execution (“Hold”/“Flip”). Each participant completed four blocks, two blocks each for which either Manual press button responses (“Hand epochs”) or saccades were made to the left or right (“Eye epochs”).
Mentions: A schematic of the task is shown in Figure 1. Each trial in the task began with the presentation of a blue or yellow colored circle (the response contingent Cue event). Subjects made a left or right behavioral response dependent upon the color of the cue and the current rule linking color with direction. For “Eye” (saccade) blocks participants were instructed to fixate one of two peripheral response locations (marked by two onscreen response boxes located approximately five degrees to the left or right of the central location and displayed during Eye epochs only). When the cue stimulus was extinguished they then had to make a return saccade to fixate the central location. The word “hold” or “flip” was then presented at fixation to indicate to the participant whether to hold or reverse the current rule on the following trial (Feedback event). In order to resolve the fMRI response to these discrete events within a trial i.e., Cue and Feedback, the period between each event and trial was varied randomly between 2200, 4400 and 10200 ms such that inter-event intervals did not correspond to multiples of the TR period. Varying the period between individual events in this manner within as well as between trials ensures that discrete events can be resolved within a trial (Parris et al., 2007).

Bottom Line: Participants performed a rule switching task using different effector modalities.Multivariate analysis revealed that the pattern of activity evoked by Flip rule Feedbacks within an apparently supra modal frontal region (dorsolateral frontal cortex) discriminated between response epochs.The results are consistent with the existence of multi-modal representations of stimulus-response (SR) rules within the frontal cerebral cortex.

View Article: PubMed Central - PubMed

Affiliation: School of Psychology, University of Lincoln Lincoln, UK.

ABSTRACT
We report a functional magnetic resonance imaging (fMRI) study which investigated whether brain areas involved in updating task rules within the frontal lobe of the cerebral cortex show activity related to the modality of motor response used in the task. Participants performed a rule switching task using different effector modalities. In some blocks participants responded with left/right button presses, whilst in other blocks left/right saccades were required. The color of a Cue event instructed a left or right response based upon a rule, followed by a Feedback which indicated whether the rule was to stay the same or "Flip" on the next trial. The findings revealed variation in the locus of activity within the ventrolateral frontal cortex dependent upon effector modality. Other frontal areas showed no significant difference in activity between response epochs but changed their pattern of connectivity with posterior cortical areas dependent upon response. Multivariate analysis revealed that the pattern of activity evoked by Flip rule Feedbacks within an apparently supra modal frontal region (dorsolateral frontal cortex) discriminated between response epochs. The results are consistent with the existence of multi-modal representations of stimulus-response (SR) rules within the frontal cerebral cortex.

No MeSH data available.