The influence of dopamine on prediction, action and learning

Chorley, Paul (2012) The influence of dopamine on prediction, action and learning. Doctoral thesis (DPhil), University of Sussex.

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Abstract

In this thesis I explore functions of the neuromodulator dopamine in the context
of autonomous learning and behaviour. I first investigate dopaminergic influence
within a simulated agent-based model, demonstrating how modulation of
synaptic plasticity can enable reward-mediated learning that is both adaptive and
self-limiting. I describe how this mechanism is driven by the dynamics of agentenvironment
interaction and consequently suggest roles for both complex spontaneous
neuronal activity and specific neuroanatomy in the expression of early, exploratory
behaviour. I then show how the observed response of dopamine neurons
in the mammalian basal ganglia may also be modelled by similar processes involving
dopaminergic neuromodulation and cortical spike-pattern representation within
an architecture of counteracting excitatory and inhibitory neural pathways, reflecting
gross mammalian neuroanatomy. Significantly, I demonstrate how combined
modulation of synaptic plasticity and neuronal excitability enables specific (timely)
spike-patterns to be recognised and selectively responded to by efferent neural populations,
therefore providing a novel spike-timing based implementation of the hypothetical
‘serial-compound’ representation suggested by temporal difference learning.
I subsequently discuss more recent work, focused upon modelling those complex
spike-patterns observed in cortex. Here, I describe neural features likely to contribute
to the expression of such activity and subsequently present novel simulation
software allowing for interactive exploration of these factors, in a more comprehensive
neural model that implements both dynamical synapses and dopaminergic
neuromodulation. I conclude by describing how the work presented ultimately suggests
an integrated theory of autonomous learning, in which direct coupling of agent
and environment supports a predictive coding mechanism, bootstrapped in early
development by a more fundamental process of trial-and-error learning.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Engineering and Informatics > Informatics
Subjects: B Philosophy. Psychology. Religion > BF Psychology > BF0207 Psychotropic drugs and other substances
B Philosophy. Psychology. Religion > BF Psychology > BF0309 Consciousness. Cognition Including learning, attention, comprehension, memory, imagination, genius, intelligence, thought and thinking, psycholinguistics, mental fatigue
R Medicine > RM Therapeutics. Pharmacology > RM0300 Drugs and their actions
Depositing User: Library Cataloguing
Date Deposited: 20 Jun 2012 07:55
Last Modified: 04 Sep 2015 13:24
URI: http://sro.sussex.ac.uk/id/eprint/39650

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