Chance Christensen, Utah State University
Psychology
Affective disorders such as depression, phobias, schizophrenia, and post-traumatic stress disorder impairs the ability to time in the seconds-to-minutes range, i.e., interval timing. We investigated the effect of chronic administration of selective serotonin reuptake inhibitor fluoxetine(FLX) when anxiety-inducing task-irrelevant distracters are presented during an interval timing task. According to the Relative Time-Sharing (RTS) model, presentation of task-irrelevant distracters during a timing task results in a delay in responding suggesting a failure to maintain subjective time in working memory, possibly due to attentional and working memory resources being diverted away from timing. Given that some anti-depressants have beneficial effects on attention and working memory, e.g., decreasing emotional response to negative events, we hypothesized that FLX would improve maintenance of information in working memory in trials with distracters, resulting in a decrease of the disruptive effect of emotional events on the timekeeping abilities. Our results revealed independent effects of FLX on timing and resource allocation. Acute administration of FLX delayed timing, but this effect was eliminated after chronic administration. FLX reduced the detrimental effect of the distracters only when the distracters were anxiety-inducing, but not when they were neutral. Results are discussed in relation to the brain circuits involved in RTS of resources, and the pharmacological management of affective disorders.