The effect of Cabergoline, a dopamine D2 agonist, on spatial attention bias: A double blind randomised control trial

Abstract

Every day individuals are bombarded with extraneous visual stimuli and consequently rely on selective spatial attention to effectively process task relevant information. However, individuals often show asymmetries in their spatial attention, a phenomenon known as spatial attention bias. Neuroanatomical, neurochemical, lesion, and genetic studies have converged to implicate dopamine, a catecholamine transporter, in modulating spatial attention bias. The current study utilised a double blind randomised control trial cross-over design to investigate the effect of Cabergoline, a dopamine D2 agonist, on spatial attention bias. Participants consisted of 24 healthy males and underwent the Greyscales task, a well-validated perceptual measure of attentional bias, and a novel visual search task, to investigate how an increase in dopamine affected spatial attentional performance. It was hypothesised that Cabergoline would increase dopamine availability in the right hemisphere and drive attention leftwards. This was not supported by the Greyscales task however was partially supported by the novel visual search task as when participant’s responded under conditions of increased perceptual load, results suggested Cabergoline may have shifted attention leftwards which subsequently resulted in reduced attentional abilities available to deal with stimuli presented in the right hemifield. Furthermore, Cabergoline may have increased selective attention in the right hemifield when there were no competing distractors present from the left hemifield. Understanding how different neurotransmitters influence spatial attention and spatial bias is important as it may aid in the development of pharmacological treatments for clinical populations where spatial deficits are prominent