Three weeks of SSRI administration enhances the visual perceptual threshold - a randomized placebo-controlled study
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The serotonergic system has been repeatedly linked to visual attention in general, but the effects of selective serotonin reuptake inhibitor (SSRI) on specific components of visual attention remain unknown. Changes in distinct perceptual and cognitive processes are not readily evident in most attention paradigms.
In this study, we isolate basic components of visual attention to investigate potential effects of longer-term SSRI administration on non-emotional aspects of visual attention in healthy males.
In a randomized double-blind placebo-controlled design, 32 young healthy males were tested on multiple attentional parameters, before and after a 3-week SSRI intervention with fluoxetine (40 mg daily) or placebo. Data were modeled with a computational theory of visual attention to derive independent estimates of five distinct components of visual attention.
The SSRI intervention selectively and significantly lowered the threshold for conscious visual perception. Specifically, we demonstrate that this improvement does not stem from a general increase in the speed of visual processing, as previously suggested, but specifically from a change in the perceptual threshold.
The study provides a novel description of the attentional dynamics affected by SSRI, while supporting previous findings on attentional effects of SSRI. Furthermore, it accentuates the utility of employing accuracy-based measures of attentional performance when conducting psychopharmacological research.
KeywordsSSRI Serotonin 5-HT Attention Perception Cognition Non-motor Unspeeded response Healthy Human TVA Theory of visual attention
The project was funded by a center grant from the Lundbeck Foundation to Center for Integrated Molecular Brain Imaging (Cimbi, www.cimbi.dk). JL is supported by a grant from the Lundbeck Foundation: Attention, impulsivity, and monoamines: from psychological functions to molecular mechanisms.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
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