Oscillatory brain dynamics supporting impaired Stroop task performance in schizophrenia-spectrum disorder

Area of Science:

• Neuroscience
• Cognitive Psychology
• Psychiatry

Background:

• The Stroop color-word interference task is crucial for studying inhibitory control and its dysfunction in schizophrenia.
• Inconsistent findings regarding the Stroop effect in schizophrenia hinder understanding of underlying neural mechanisms.

Purpose of the Study:

• To investigate neural oscillatory dynamics during interference detection and response preparation in schizophrenia spectrum disorders.
• To differentiate between normal and impaired neural processes using EEG during the Stroop task.

Main Methods:

• Analysis of behavioral performance and EEG oscillations (theta and alpha/beta bands) in 40 patients with schizophrenia (SZ) and 27 healthy controls (HC).
• Examined dorsal anterior cingulate (dACC) theta enhancement, dACC-sensorimotor cortex connectivity (theta phase synchrony), and alpha/beta suppression during incongruent (INC) trials.

Main Results:

• SZ exhibited slower responses, reduced dACC theta enhancement, and impaired dACC-sensorimotor theta phase synchrony during INC trials compared to HC.
• SZ showed altered alpha/beta suppression patterns and slower post-response alpha/beta rebound.
• Slower reaction times correlated with larger group and Stroop effects, particularly in the slowest quartile of trials.

Conclusions:

• Poorer theta phase coherence in SZ suggests impaired communication between dACC and sensorimotor cortex, impacting interference processing and response preparation.
• Compromised behavioral Stroop effects in schizophrenia may stem from a failure cascade initiated by dysfunctional interference processing and motor response preparation.
• Variability in past Stroop task parameters might explain inconsistent findings in schizophrenia research.