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Distinct roles of dopamine and subthalamic nucleus in learning and probabilistic decision making.
- Source :
-
Brain : a journal of neurology [Brain] 2012 Dec; Vol. 135 (Pt 12), pp. 3721-34. Date of Electronic Publication: 2012 Oct 31. - Publication Year :
- 2012
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Abstract
- Even simple behaviour requires us to make decisions based on combining multiple pieces of learned and new information. Making such decisions requires both learning the optimal response to each given stimulus as well as combining probabilistic information from multiple stimuli before selecting a response. Computational theories of decision making predict that learning individual stimulus-response associations and rapid combination of information from multiple stimuli are dependent on different components of basal ganglia circuitry. In particular, learning and retention of memory, required for optimal response choice, are significantly reliant on dopamine, whereas integrating information probabilistically is critically dependent upon functioning of the glutamatergic subthalamic nucleus (computing the 'normalization term' in Bayes' theorem). Here, we test these theories by investigating 22 patients with Parkinson's disease either treated with deep brain stimulation to the subthalamic nucleus and dopaminergic therapy or managed with dopaminergic therapy alone. We use computerized tasks that probe three cognitive functions-information acquisition (learning), memory over a delay and information integration when multiple pieces of sequentially presented information have to be combined. Patients performed the tasks ON or OFF deep brain stimulation and/or ON or OFF dopaminergic therapy. Consistent with the computational theories, we show that stopping dopaminergic therapy impairs memory for probabilistic information over a delay, whereas deep brain stimulation to the region of the subthalamic nucleus disrupts decision making when multiple pieces of acquired information must be combined. Furthermore, we found that when participants needed to update their decision on the basis of the last piece of information presented in the decision-making task, patients with deep brain stimulation of the subthalamic nucleus region did not slow down appropriately to revise their plan, a pattern of behaviour that mirrors the impulsivity described clinically in some patients with subthalamic nucleus deep brain stimulation. Thus, we demonstrate distinct mechanisms for two important facets of human decision making: first, a role for dopamine in memory consolidation, and second, the critical importance of the subthalamic nucleus in successful decision making when multiple pieces of information must be combined.
- Subjects :
- Analysis of Variance
Decision Making drug effects
Deep Brain Stimulation methods
Dopamine Agents therapeutic use
Female
Humans
Learning drug effects
Male
Middle Aged
Neuropsychological Tests
Photic Stimulation
Psychomotor Performance drug effects
Psychomotor Performance physiology
Reaction Time drug effects
Time Factors
Decision Making physiology
Dopamine metabolism
Learning physiology
Parkinson Disease metabolism
Parkinson Disease physiopathology
Parkinson Disease therapy
Probability
Subthalamic Nucleus physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1460-2156
- Volume :
- 135
- Issue :
- Pt 12
- Database :
- MEDLINE
- Journal :
- Brain : a journal of neurology
- Publication Type :
- Academic Journal
- Accession number :
- 23114368
- Full Text :
- https://doi.org/10.1093/brain/aws273