title: Neo-striatal rCBF correlates of psychomotor slowing in patients with major depression.
abstract: Psychomotor slowing is a fundamental clinical feature of severe depression and is thought to reflect dysfunction within prefrontal-subcortical circuits. This study utilised a split-dose single photon emission computerised tomography (SPECT) scanning technique in association with a two-stage test of psychomotor speed. Twenty-five patients with primary depressive disorders were injected with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) whilst performing each component of a two-stage psychomotor task. The first stage, 'simple reaction time' (RT) and the second stage, 'choice reaction time' (CRT), were each followed by 30-min SPECT scans. Regions of interest (ROIs) corresponding to the left and right neo-striatum (caudate-putamen) were drawn, and regional cerebral blood flow (rCBF) values were calculated. Importantly, the change in rCBF measure in the left neo-striatum was inversely correlated with RT (r = -0.48, P < 0.05). That is, the patients with the greatest psychomotor slowing initially showed the least increase in rCBF during the CRT condition. This effect was independent of age. The study demonstrates that a simple two-stage motor paradigm can be used to elicit rCBF correlates of psychomotor slowing in patients with primary depression. Such rCBF findings may implicate the neo-striatum in the neurobiology of major depression.
authors.affiliation: School of Psychiatry, University of New South Wales, Sydney, Australia. i.hickie@unsw.edu.au
authors.forename: I
authors.initials: I
authors.lastname: Hickie
authors.forename: P
authors.initials: P
authors.lastname: Ward
authors.forename: E
authors.initials: E
authors.lastname: Scott
authors.forename: W
authors.initials: W
authors.lastname: Haindl
authors.forename: B
authors.initials: B
authors.lastname: Walker
authors.forename: J
authors.initials: J
authors.lastname: Dixon
authors.forename: K
authors.initials: K
authors.lastname: Turner
mesh_terms: D000328:Adult; D000368:Aged; D003342:Corpus Striatum / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011596:Psychomotor Disorders / Q000209:etiology*; D019275:Radiopharmaceuticals; D011930:Reaction Time; D019690:Technetium Tc 99m Exametazime; D015899:Tomography, Emission-Computed, Single-Photon
chemical_list: D019275:Radiopharmaceuticals; D019690:Technetium Tc 99m Exametazime