Rigidity in error monitoring: Altered oscillatory dynamics under speed and accuracy instructions in obsessive-compulsive disorder.

The ability to detect errors and adjust one's own behavior accordingly is fundamental to successful adaptations in dynamic environments. Errors elicit a negative frontocentral deflection in the event-related potential, i.e., error-related negativity (ERN). Moreover, they lead to an oscillatory burst in theta and delta ranges. Theta has been proposed to reflect a mechanism communicating the need for cognitive control across prefrontal brain regions. Error processing and theta and delta power have been repeatedly shown to be increased in patients with obsessive-compulsive disorder (OCD). In addition, OCD patients show reduced adjustments in error monitoring under speed and accuracy instructions. However, it remains unclear to what extent this finding is associated with altered theta and delta dynamics. Therefore, this study aims to analyze error-related oscillatory brain activity and behavioral adaptation in OCD patients under speed and accuracy instructions. We analyzed data from 25 healthy participants and 24 OCD patients applying a time-frequency analysis (complex Morlet wavelets) and a frequency-based coherence analysis to assess functional connectivity between medio-lateral prefrontal brain areas. Results indicate an overall increase in oscillatory activity due to the accuracy-focused instruction. However, no significant difference was found, i.e., no flexible adaptation between the speed and accuracy conditions for OCD patients as reflected in reduced variations of error-related delta activity. Furthermore, increased prefrontal connectivity explains exaggerated accuracy under speed focus as a result of overactive cognitive control in OCD patients. This supports the hypothesis that the flexibility of error monitoring is reduced, and cognitive control is increased in OCD patients.