value-based decision-making and the prefrontal cortex jon wallis
DESCRIPTION
Value-based decision-making and the prefrontal cortex JON WALLIS. Animal models of decision-making. Outline. Define the theoretical constructs underpinning our understanding of decision-making Discuss the anatomical and functional homologies between humans and monkeys - PowerPoint PPT PresentationTRANSCRIPT
Value-based decision-making and the prefrontal cortex
JON WALLIS
Animal models of decision-making
Action selection
Vigor/Arousal
Motivation
Cortex
Accumbens
Hypothalamus
Outline
• Define the theoretical constructs underpinning our understanding of decision-making
• Discuss the anatomical and functional homologies between humans and monkeys
• Describe my research into the role of frontal cortex in decision-making
• Clinical and pharmacological implications
Types of decision-makingValue-based
decision-making
• no right or wrong
• subjective • objective reality
Perceptual decision-making
Decisionboundary
‘CAT’ ‘DOG’
Theoretical constructs: perceptual decision-making
Theoretical constructs: value-based decision-making
Neuropsychology and choice behavior
Which is more blue?
Perceptual decision-making
Value-based decision-making
Which do you prefer?Lateral PFC
Orbital/medial PFC
Fellows and Farah (2007)
Outline
• Define the theoretical constructs underpinning our understanding of decision-making
• Discuss the anatomical and functional homologies between humans and monkeys
• Describe my research into the role of frontal cortex in decision-making
• Clinical and pharmacological implications
PFo homology
PFm homology
Role of PFo in valuation
2
1
8
1
1
4
1
2
2
1
4
4
1
12
12
1
16
16Chosen Value :
Padoa-Schioppa and Assad (2006)
3
1
12
=
Neuroimaging and valuation
Fast for 4 hours
Bid on 40 different food items
Given 3 dollars
($1.50)
($2.00)
Hare et al (2008)
PFo and “neuronal currency”
Payoff+
Time
Effort
Risk
-- -
+
(1500 ms)Choice
9 6 4 2 1
Probability
Encoding decision variables across PFC
All three variables: abstract value
Kennerley et al (2009, J Cog Neuro)
ValuePictures Appear
GoCue
One variable (cost)
Kennerley et al (2009, J Cog Neuro)
Value
Two variables (payoff and cost)
Kennerley et al (2009, J Cog Neuro)
Value
Recording locations
PFlPFoPFm
PFl
PFo
PFm
Prevalence of different types of value encoding
Kennerley et al (2009, J Cog Neuro)
Cost CostCost
Complex types of value encoding are in PFm
Kennerley et al (2009, J Cog Neuro)
0
35
One variable Two variables Three variables
% s
elec
tive
neur
ons
LPFC
OFC
MPFC
% n
euro
ns
PFm
PFo
PFl
The importance of PFo and PFcs for decision-making, may depend on their ability to multiplex different decision parameters.
Cost-benefit analysisRe
ward
(mls)
Effort (lbs)
Effort-baseddecision-making
Rewa
rd (m
ls)Delay (s)
Delay-baseddecision-making
5 8 11 14 1.8 3 4.2 5.4
Probability of selecting picture
Reward Effort
Value0.4 g
0.1 g
5 lbs
14 lbs
PFm neuron: net value
Outline
• Define the theoretical constructs underpinning our understanding of decision-making
• Discuss the anatomical and functional homologies between humans and monkeys
• Overview of our current understanding of the role of frontal cortex in decision-making
• Overview of the pharmacological results based on this understanding
Clinical implications: depression
• Depression is associated with metabolic and neurochemical changes in PFm
• also characterized by anhedonia and anergia
• does this reflect changes to the effort/reward function?
Decreased metabolic activity in depressed patients
Clinical implications: delay-based decision-making
• Impulsive decisions occur in:
– substance abusers (e.g. Monterosso et al 2001)
– schizophrenics (e.g. Heerey et al 2007)
– alcoholics (Boettiger et al 2007)
– individuals with the COMT 158Val/Val genotype (Boettiger et al 2007)
Pharmacological considerations: dopamine
• dopamine agonists make rats more patient (e.g. Floresco et al 2008) or more impulsive (e.g. Cardinal et al 2001)– dose-response curve?
• OFC 6-OHDA lesions make rats more patient (Kheramin et al 2004)
DELAY-BASED DECISION-MAKING:
• nucleus accumbens dopamine depletion makes rats lazy (Salamone et al 1994)
• PFm D1 antagonist infusion makes rats lazy (Schweimer & Hauber 2006)
EFFORT-BASED DECISION-MAKING:
Pharmacological considerations: serotonin
• blockade of serotonin synthesis makes rats more impulsive (Denk et al 2004)
• in vivo microdialysis reveals changes in serotonin metabolite levels in PFm during delay-based decision-making (Winstanley et al 2006)
DELAY-BASED DECISION-MAKING:
• blockade of serotonin synthesis has no effect (Denk et al 2004)
EFFORT-BASED DECISION-MAKING:
Conclusions
• the orbital and medial prefrontal areas are particularly important for decision-making
• there is good anatomical and functional homology between these regions in the human and monkey
• disparate clinical symptoms (e.g. anhedonia, impulsivity) might be better understood as disorders of underlying decision-making calculations
Conclusion
Emotional/Social dysfunction
Reward processing
Behavioral and clinical level
Single neuron, genetic andpharmacological level
Conclusion
Emotional/Social dysfunction
Valuation and decision-making
Reward processing
Behavioral and clinical level
Single neuron, genetic andpharmacological level
Computational level
Acknowledgements
Steven KennerleyAsst. Prof.
University College London
Antonio LaraGraduate student
Chung-Hay LukGraduate student
Jen SloanGraduate student
Shima OvaysikiaResearch assistant