Neuro-hemodynamic endophenotypes of emotional interference in OCD: fMRI study using emotion counting stroop task

Area of Science:

• Neuroscience
• Psychiatry
• Medical Imaging

Background:

• Obsessive-compulsive disorder (OCD) is a complex psychiatric condition.
• Understanding the neurobiological underpinnings of OCD is crucial for developing effective treatments.
• Endophenotypes can serve as objective markers for genetic vulnerability.

Purpose of the Study:

• To investigate the neuro-hemodynamic differences in brain activity during an emotion counting Stroop (ecStroop) task.
• To compare patients with OCD, their unaffected first-degree relatives (FDRs), and healthy controls (HC).
• To identify potential endophenotypes related to the processing of threat-related stimuli in OCD.

Main Methods:

• Utilized a 3-Tesla functional magnetic resonance imaging (fMRI) scanner.
• Employed an established ecStroop paradigm with three conditions: neutral words (N), negative emotional words (E), and OCD-salient words (O).
• Analyzed relative Blood-Oxygen-Level-Dependent (BOLD) signals in pre-defined brain regions.

Main Results:

• Significant differential activation in the right insula (BA 13) was observed across groups for O vs. N and O vs. E contrasts.
• Patients and FDRs showed significantly greater insula activation than HC in the O vs. E contrast.
• Patients and FDRs exhibited heightened activation in the right insula and right dorsolateral prefrontal cortex (DLPFC, BA 9) compared to HC in the O vs. N contrast.

Conclusions:

• Neuro-hemodynamic responses in the insula and DLPFC to obsessive words may represent potential endophenotypes for OCD.
• "Threat relatedness" processing could play a role in the vulnerability and neurobiological basis of OCD.
• These findings contribute to understanding the genetic and neural mechanisms underlying OCD.