What is odd in the oddball task? Prefrontal cortex is activated by dynamic changes in response strategy

Area of Science:

• Cognitive Neuroscience
• Neuroimaging

Background:

• The oddball task reveals prefrontal cortex activity, but its cause (response selection vs. strategy change) is unclear.
• Investigating the neural basis of dynamic response strategy adjustments is crucial for understanding cognitive control.

Purpose of the Study:

• To differentiate between response selection and strategy change in oddball task-related prefrontal activation.
• To examine the role of the prefrontal cortex in adapting stimulus-response mappings.

Main Methods:

• Utilized a novel oddball task incorporating the Simon effect.
• Measured hemodynamic brain activity using functional magnetic resonance imaging (fMRI).
• Analyzed brain activity in anterior middle frontal gyrus (MFG), inferior frontal gyrus (IFG), insular cortex, and anterior cingulate gyrus (ACG).

Main Results:

• Infrequent "strategy-change" trials elicited significant activation in MFG, IFG, insular cortex, and ACG.
• Behavioral data confirmed subjects employed and inhibited a position-based response strategy.
• Activity in MFG and ACG correlated with error rates, while IFG activity did not.

Conclusions:

• Dorsolateral prefrontal cortex (dlPFC) is involved in dynamically updating stimulus-response mappings.
• Prefrontal activation reflects strategic adjustments rather than solely infrequent response selection.
• The findings dissociate neural activity related to strategy changes from behavioral performance.