A model of reversal learning and working memory in medicated and unmedicated patients with Parkinsons disease

dc.contributor.author Herzallah, Mohammed
dc.contributor.author Moustafa, Ahmed
dc.contributor.author Gluck, Mark
dc.date.accessioned 2018-08-12T11:13:20Z
dc.date.available 2018-08-12T11:13:20Z
dc.date.issued 2014-10-18
dc.description.abstract Wepresent a neural network model of cognition in medicated and unmedicated patients with Parkinson’s disease (PD) in various learning and memory tasks. The model extends our prior models of the basal ganglia and PD with further modeling of the role of prefrontal cortex (PFC) dopamine in stimulus–response learning, reversal, and working memory. In our model, PD is associated with decreased dopamine levels in the basal ganglia and PFC, whereas dopamine medications increase dopamine levels in both brain structures. Simulation results suggest that dopamine medications impair stimulus–response learning in agreement with experimental data (Breitenstein et al., 2006; Gotham, Brown, & Marsden, 1988). Weshow how decreased dopamine levels in the PFC in unmedicated PD patients are associated with impaired working memory performance, as seen experimentally (Costa et al., 2003; Lange et al., 1992; Moustafa, Sherman, & Frank, 2008; Owen, Sahakian, Hodges, Summers, & Polkey, 1995). Further, our model simulations illustrate how increases in tonic dopamine levels in the PFC due to dopamine medications will enhance working memory, in accord with previous modeling and experimental results (Cohen, Braver, & Brown, 2002; Durstewitz, Seamans, & Sejnowski, 2000; Wang, Vijayraghavan, & Goldman-Rakic, 2004). The model is also consistent with data reported in Cools, Barker, Sahakian, and Robbins (2001), who showed that dopamine medications impair reversal learning. In addition, our model shows that extended training of the reversal phase leads to enhanced reversal performance in medicated PD patients, which is a new, and as yet untested, prediction of the model. Overall, our model provides a unified account for performance in various behavioral tasks using common computational principles. en_US
dc.description.sponsorship Research reported in this publication was supported by National Institutes of Health Award 1 P50 NS 071675-02 from the National Institute of Neurological Disorders and Stroke and by a 2013 internal UWS Research Grant Scheme award P00021210 to A.A.M. en_US
dc.identifier.issn 0022-2496
dc.identifier.uri https://dspace.alquds.edu/handle/20.500.12213/731
dc.language.iso en_US en_US
dc.publisher Elsevier en_US
dc.subject Stimulus–response learning en_US
dc.subject Working memory en_US
dc.subject Reversal learning en_US
dc.subject Reinforcement en_US
dc.subject Dopamine (DA) en_US
dc.subject Prefrontal cortex (PFC) en_US
dc.subject Basal ganglia (BG) en_US
dc.subject Parkinson’s disease (PD) en_US
dc.title A model of reversal learning and working memory in medicated and unmedicated patients with Parkinsons disease en_US
dc.type Article en_US
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