Abstract
Depression is often associated with cognitive control deficits, particularly difficulties inhibiting unintended cognitive and behavioral responses. However, it’s unclear how these difficulties contribute to the basic concentration symptoms associated with the disorder, where the ability to focus attention is disrupted. To fill this gap in the literature, this study explored the behavioral and neural characteristics of sustained attention in depression using the well-validated Sustained Attention to Response Task (SART). In the SART participants are presented with a series of digits from 1 to 9, and are instructed to respond as soon as possible with a button press to every digit except 3, in which case no response is made. The requirement to continuously respond to a majority of stimuli elicits automatic responding, which can lead to slips of attention and unintended responses if cognitive control over behavior is not monitored within the task. The current study used temporal principal component analysis, which parametrically separates overlapping event-related potential (ERP) components, to examine 3 ERP components that may be related to concentration difficulties in depression. Two standard components are related to inhibition, the N2 and P3 were observed to be increased during NoGo digit 3 trials, and are considered to reflect conflict monitoring and resource allocation for cognitive control, respectively. An additional late positivity component was also observed that is hypothesized to reflect cortical deactivation of active stimulus processing. Results showed increased levels of depression were associated with increased P3 amplitudes and reduced late positivity amplitudes during the SART. In addition, depression was unassociated with reaction time or error rate decrements. Together results suggest that depression may require increased and sustained effortful task processing to maintain performance. The results support previous evidence that inefficient cognitive control underlies depression and provides important information for describing the mechanisms of concentration difficulties in the disorder.
Acknowledgement: The current study is funded by a University of South Florida, Saint Petersburg New Researcher Award