Cognitive sequences in obsessive-compulsive disorder are supported by frontal cortex ramping activity

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• Abstract sequence completion is crucial for daily activities and involves cognitive control.
• Obsessive-compulsive disorder (OCD) may involve disruptions in abstract sequence completion due to ritualistic behaviors.
• Cognitive control in abstract sequences involves abstract sequential control and task switching, with limited research on their interplay in OCD.

Purpose of the Study:

• To investigate abstract sequential control and task switching in individuals with OCD.
• To examine neural correlates, specifically brain activity ramping, during abstract sequence completion in OCD.
• To understand how hierarchical cognitive control is affected in OCD during complex, daily-life-like behaviors.

Main Methods:

• Utilized functional magnetic resonance imaging (fMRI) to measure brain activity during abstract sequence completion tasks.
• Assessed behavioral performance on abstract sequential control and task switching paradigms.
• Analyzed brain activity patterns, focusing on "ramping" dynamics in regions like the rostrolateral prefrontal cortex (RLPFC), anterior cingulate cortex (ACC), and superior frontal sulcus (SFS).

Main Results:

• No significant behavioral differences in abstract sequential control were found between individuals with OCD and healthy controls.
• Individuals with OCD exhibited increased overall ramping in the ACC and SFS, with complexity-dependent ramping differences in other cortical regions.
• Behavioral deficits in task switching were observed in individuals with OCD, but without corresponding group differences in neural activity.

Conclusions:

• Abstract sequential control is supported by distinct neural mechanisms in OCD compared to healthy controls, even with similar behavioral performance.
• Altered neural "ramping" dynamics in specific cortical areas suggest unique processing of sequential information in OCD.
• Observed task-switching behavioral deficits in OCD are not explained by neural differences in task-related control regions, indicating a dissociation between behavior and neural activity.