title: Effects of lesions of the subthalamic nucleus/zona incerta area and dorsomedial striatum on attentional set-shifting in the rat.
abstract: Patients with Parkinson's disease (PD) show cognitive impairments, including difficulty in shifting attention between perceptual dimensions of complex stimuli. Inactivation of the subthalamic nucleus (STN) has been shown to be effective in ameliorating the motor abnormalities associated with striatal dopamine (DA) depletion, but it is possible that STN inactivation might result in additional, perhaps attentional, deficits. This study examined the effects of: DA depletion from the dorsomedial striatum (DMS); lesions of the STN area; and the effects of the two lesions together, on the ability to shift attentional set in the rat. In a single session, rats performed the intradimensional/extradimensional (ID/ED) test of attentional set-shifting. This comprises a series of seven, two-choice discriminations, including acquisitions of novel discriminations in which the relevant stimulus is either in the currently attended dimension (ID) or the currently unattended dimension (ED shift) and reversals (REVs) following each acquisition stage. Bilateral lesions were made by injection of 6-hydroxydopamine (6-OHDA) into the DMS, resulting in a selective impairment in reversal learning. Large bilateral ibotenic acid lesions centered on the STN resulted in an increase in trials to criterion in the initial stages, but learning rate improved within the session. There was no evidence of a 'cost' of set-shifting - the ED stage was completed in fewer trials than the ID stage - and neither was there a cost of reversal learning. Strikingly, combined lesions of both regions did not resemble the effects of either lesion alone and resulted in no apparent deficits.
authors: School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife KY16 9JP, UK. Electronic address: dst@st-andrews.ac.uk.
authors: David S
authors: DS
authors: Tait
authors: School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife KY16 9JP, UK.
authors: Janice M
authors: JM
authors: Phillips
authors: School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife KY16 9JP, UK.
authors: Andrew D
authors: AD
authors: Blackwell
authors: School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife KY16 9JP, UK.
authors: Verity J
authors: VJ
authors: Brown
mesh_terms: D000818:Animals; D001288:Attention / Q000502:physiology*; D003342:Corpus Striatum / Q000187:drug effects / Q000503:physiopathology*; D004193:Discrimination Learning / Q000502:physiology; D004298:Dopamine / Q000378:metabolism; D007051:Ibotenic Acid / Q000633:toxicity; D008297:Male; D009483:Neuropsychological Tests; D016627:Oxidopamine / Q000633:toxicity; D051381:Rats; D012193:Reversal Learning / Q000502:physiology*; D020531:Subthalamic Nucleus / Q000187:drug effects / Q000503:physiopathology*; D065820:Zona Incerta / Q000187:drug effects / Q000503:physiopathology*
chemical_list: D007051:Ibotenic Acid; D016627:Oxidopamine; D004298:Dopamine
keywords: Parkinson’s disease; attentional set-shifting; basal ganglia; dopamine; subthalamic nucleus