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A Neuroeconomic Approach to
Understanding Valuation of Risky
Prospects
Neal Hinvest
University of Bath
U.K.
What is neuroeconomics?
ECONOMICS
NEUROSCIENCE/
BEHAVIOURAL
NEUROSCIENCE
NEUROECONOMICS
PSYCHOLOGY
Valuation of outcomes
• How we make the best
decisions in the face of
incomplete information?
• Every outcome entails cost,
therefore, all choices are
economic decisions
• All outcomes are processed (at
or below conscious level) to
maximise potential benefit
taking into account potential
loss
• Valuations are occurring at
every moment of our lives
• Choice behaviour is based
upon these valuations
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Valuation and the brain
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To create valuations, “cold” and “hot”
information must be integrated
The dopamine system has been identified
as having a major role in reward processing
Important role in reward-prediction learning
(Montague et al, 1996; O’Reilly et al, 1999;
2002)
The dopamine system projects through the
striatum to the frontal cortex
Dorsal striatum = action selection and
reward prediction
Ventral striatum = stimulus-response
learning (for recent review see Hikosaka et
al, 2008)
PFC = integration centre for top-down
control (Miller & Cohen, 2001)
Damage to prefrontal regions leads to
dysfunction of valuation mechanisms such
as perseveration of a single action over time
and incapacity to maintain a goal online
Plausible candidate for “valuation signal” is
orbitofrontal cortex (Elliot et al. 2003;
Knutson et al. 2001; O’Doherty et al. 2001;
Bush et al., 2002)
What will be the impact of such
research?
• Identify mechanisms involved in specific aspects
of human choice behaviour, and thus provide
models of decision-making processes with
biological validity
• Answer key questions within economics and
psychology (e.g. McClure et al, 2004)
• Understand how possible alteration of the
function of valuation mechanisms may underlie
problematic behaviours (e.g. drug/gambling
abuse)
Our research
• Understanding neural substrates of
valuation of risky prospects
• Present potential gains and potential
losses
• Participants actively ascribe a personal
worth to the prospect
• Functional Magnetic Resonance Imaging
(fMRI)
Results – potential reward
• Valuation of potential
rewards is associated
with increased activity
within bilateral OFC
• Activation also
measured in frontoparieto-occipito
networks
P < .001 (uncorrected)
Results – potential loss
• Valuation of potential
losses is associated with
activity in medial frontal
regions extending from
ventral OFC through
VMPFC to dorso-medial
PFC
• Activity also measured in
fronto-parieto-occipto
networks
P < .001 (uncorrected)
P < .001 (uncorrected)
Conclusions
• Increased evidence for OFC as having a
major role in valuation
• Possible source of signal integration
• Suggestion of spatiotopic role of OFC in
reward/loss processing (Elliot et al, 2000 ;
Ursu et al, 2005; O’Doherty et al, 2003:
medial = reward, lateral = loss)
Evidence for altered function of
OFC in psychiatric samples
• Pathological gamblers and drug abusers
exhibit evidence of biased valuation
mechanisms that place larger worth on
addiction-related cues
• This has been associated with dysfunction
within dopamine-fed systems, most
importantly, the prefrontal cortex
• Presented substance abusers and
pathological gamblers with a delay
discounting task
• Outcomes are presented for 3s, then
participant is free to choose
Results
• Drug abusers and pathological
gamblers exhibit hyperactivation of a similar region of
lateral dorsal OFC compared
to controls when evaluating
outcomes
• This occurred even though
there were no significant
differences in choice behaviour
• Represents existence of
increased neural ‘effort’ to
maintain behaviour at
comparable levels to nonaddicted groups (Padula et al,
2007)?
Pathological gamblers
Substance abusers
Conclusions
• Increased evidence for role of OFC in
valuation of risky outcomes
• Possible existence of two overlapping
systems for valuation of potential rewards
and potential losses
• Evidence for altered function of OFC in
addiction-disordered groups (underlie
biased valuations?)
Acknowledgements
University of Bath
Alan Lewis
John Cullis
University of Warwick
Gemma Calvert
University of Exeter
Tim Hodgson
University of Oxford
Rob Rogers
University of Manchester
Ian Anderson
Rebecca Elliott
Shane McKie