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Catecholaminergic Regulation of Learning Rate in a Dynamic Environment.
- Source :
-
PLoS computational biology [PLoS Comput Biol] 2016 Oct 28; Vol. 12 (10), pp. e1005171. Date of Electronic Publication: 2016 Oct 28 (Print Publication: 2016). - Publication Year :
- 2016
-
Abstract
- Adaptive behavior in a changing world requires flexibly adapting one's rate of learning to the rate of environmental change. Recent studies have examined the computational mechanisms by which various environmental factors determine the impact of new outcomes on existing beliefs (i.e., the 'learning rate'). However, the brain mechanisms, and in particular the neuromodulators, involved in this process are still largely unknown. The brain-wide neurophysiological effects of the catecholamines norepinephrine and dopamine on stimulus-evoked cortical responses suggest that the catecholamine systems are well positioned to regulate learning about environmental change, but more direct evidence for a role of this system is scant. Here, we report evidence from a study employing pharmacology, scalp electrophysiology and computational modeling (N = 32) that suggests an important role for catecholamines in learning rate regulation. We found that the P3 component of the EEG-an electrophysiological index of outcome-evoked phasic catecholamine release in the cortex-predicted learning rate, and formally mediated the effect of prediction-error magnitude on learning rate. P3 amplitude also mediated the effects of two computational variables-capturing the unexpectedness of an outcome and the uncertainty of a preexisting belief-on learning rate. Furthermore, a pharmacological manipulation of catecholamine activity affected learning rate following unanticipated task changes, in a way that depended on participants' baseline learning rate. Our findings provide converging evidence for a causal role of the human catecholamine systems in learning-rate regulation as a function of environmental change.<br />Competing Interests: The authors have declared that no competing interests exist.
- Subjects :
- Adolescent
Adult
Brain Mapping methods
Dopamine metabolism
Double-Blind Method
Female
Humans
Male
Neurotransmitter Agents metabolism
Norepinephrine metabolism
Young Adult
Adaptation, Physiological physiology
Catecholamines metabolism
Ecosystem
Learning physiology
Neuronal Plasticity physiology
Parietal Lobe physiology
Subjects
Details
- Language :
- English
- ISSN :
- 1553-7358
- Volume :
- 12
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- PLoS computational biology
- Publication Type :
- Academic Journal
- Accession number :
- 27792728
- Full Text :
- https://doi.org/10.1371/journal.pcbi.1005171