title: Brain monoamines and early visual information-processing speed.
abstract: Visual inspection time (IT) is a measure of information-processing speed, which correlates reliably with psychometric intelligence. Pharmacological research into IT indicates that manipulation of the cholinergic system modulates performance on the IT task, however the contribution of other neurotransmitters to this modality remains unclear. This study was designed to examine the effects of low brain serotonin and catecholamine availability on IT using the established method of amino-acid precursor depletion. Female participants (n=13) completed three experimental sessions; tryptophan depletion (TD); tyrosine/phenylalanine depletion (TPD); and a balanced control condition (B) in a randomized, double-blind cross-over design. IT assessments were performed at baseline and approx. 5 h post-mixture administration. IT scores were unaffected by either of the treatment conditions. These findings suggest that monoamines, whilst implicated in various forms of cognition are not central to IT, which measures the efficiency of perceptual intake and information-processing speed.
authors.affiliation: Neuropharmacology Laboratory, Brain Sciences Institute, Swinburne University of Technology Melbourne, Australia.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Harrison
authors.forename: James S
authors.initials: JS
authors.lastname: Olver
authors.forename: Trevor R
authors.initials: TR
authors.lastname: Norman
authors.forename: Pradeep J
authors.initials: PJ
authors.lastname: Nathan
mesh_terms: D000328:Adult; D000596:Amino Acids / Q000097:blood / Q000378:metabolism; D015306:Biogenic Monoamines / Q000502:physiology*; D001923:Brain Chemistry / Q000502:physiology*; D018592:Cross-Over Studies; D004192:Discrimination, Psychological / Q000187:drug effects / Q000502:physiology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D010649:Phenylalanine / Q000172:deficiency; D012701:Serotonin / Q000378:metabolism; D014364:Tryptophan / Q000172:deficiency; D014443:Tyrosine / Q000172:deficiency; D014796:Visual Perception / Q000502:physiology*
chemical_list: D000596:Amino Acids; D015306:Biogenic Monoamines; D012701:Serotonin; D014443:Tyrosine; D010649:Phenylalanine; D014364:Tryptophan