What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The...
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![Page 1: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/1.jpg)
What is a decision, and what’s going on in the brain?
Elisabeth Rounis and Louise Whiteley
The mathematical brain:
![Page 2: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/2.jpg)
What is a decision?
DecisionShort- vs
Long-termgain
ContextRisk
Information gathering
Prior Beliefs
Value
Choosing between different options….
![Page 3: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/3.jpg)
What is involved in making decisions?
OR ?
![Page 4: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/4.jpg)
Value
DecisionShort- vs. Long-term
gain
Context
Risk
Information gathering
Priors
Value
![Page 5: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/5.jpg)
What is involved in making decisions?
OR
?
![Page 6: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/6.jpg)
Short- vs. Long-term gain
DecisionShort- vs Long-term
gain
Context
Risk
Information gathering
Prior Beliefs
Value
![Page 7: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/7.jpg)
What is involved in making decisions?You have:
What would you rather… OR ?
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Context
DecisionShort- vs
Long-termgain
Context
Risk
Information gathering
Prior Beliefs
Value
![Page 9: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/9.jpg)
What is involved in making decisions?
OR
![Page 10: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/10.jpg)
Risk
DecisionShort- vs
Long-termgain
ContextRisk
Information gathering
Prior Beliefs
Value
![Page 11: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/11.jpg)
What is involved in making decisions?
Healthy? Or not?
![Page 12: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/12.jpg)
Information gathering
DecisionShort- vs
Long-termgain
Context
Risk
Information gathering
Prior Beliefs
Value
![Page 13: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/13.jpg)
What is involved in making decisions?
Vs.
Wartime Peacetime
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Prior beliefs
DecisionShort- vs
Long-termgain
Context
Risk
Information gathering
Prior Beliefs
Value
![Page 15: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/15.jpg)
What is involved in making a decision?
A model that helps us understand decision making, predict behaviour, and know kind of signals to look for in the brain…
DecisionShort- vs
Long-termgain
ContextRisk
Information gathering
Prior Beliefs
Value
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How do we link brain, behaviour, and theory?
DecisionShort- vs
Long-termgain
Context
Risk
Information gathering
Prior Beliefs
Value
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Do a behavioural study…Non-Dieters Dieters
What happens in the brain? What are the differences in decision between dieters
and non-dieters?
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Brain has specialised areas that are interconnected… but what do these areas do?
Thinking, planning, moving
Feeling, recognising
Seeing
Understanding
‘Higher’ Order areas located in front…
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… Recording directly from brain cells (‘neurons’)
Neuron 1
Neuron 2
Aver
age
activ
ity
Time
dendrites
soma
axon
synapses
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Functional Imaging of whole brain regions
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What is involved in a decision?
DecisionShort- vs
Long-termgain
ContextRisk
Information gathering
Prior Beliefs
Value
![Page 22: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/22.jpg)
Information gathering
OR
Healthy? Or not?
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Information gathering• Enigma code breakers - how much time can you sacrifice to gather more information?
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Investigating information gathering in the brain
1. Think of a really simple decision
2. Find neurons in the brain that carry information important for our decision
3. Find neurons in the brain that add up this information over time
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1. A really simple decision…Which overall direction are the dots moving in?
0% coherence (random)
100% coherence(all in one direction)50% coherence
The more random dots there are, the longer you need to work out the direction of the non-random onesi.e. the more information you need to gather…
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Random dots
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Random dots… Can you see a direction?
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Random dots… now they’re moving right!
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2. Neurons that care about motion… First, we need to find an area where the brain cells (neurons) carry information about the direction of motion…
Area MT neurons respond more to a ‘preferred’ direction Stimulating neurons that prefer ‘down’ produces ‘motion hallucinations’
MTac
tivity
of n
euro
ns
preferred direction
Britten et al. 2002, Huk and Shadlen 2005
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3. Tracking information, adding it up…
MT
LIP
Gold and Shadlen 2007
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Video of activity in LIP
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Video of activity in LIP
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Video of activity in LIP
Roitman and Shadlen 2002
• Note the cell is always active but more so in the presence of the targets and as evidence accumulates
• Activity is lower if decision-maker has to choose a target that is not in the preferred direction of the cell
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So we’ve looked at dots, but there’s lots of other stuff in the world too - a range of brain areas track and gather
information
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What is involved in making decisions?
DecisionShort- vs
Long-termgain
ContextRisk
Information gathering
Prior Beliefs
Value
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Prior Knowledge
Healthy? Or not?
What if we now find out the patient smokes 50 a day?
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Prior Knowledge
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Prior knowledge affects perceptionWhat colour is a banana? YELLOW!!!
If you show people lots of bananas of different shades along the blue-yellow spectrum and ask them which one is grey?
they pick a slightly blue one, because our expectation that they will be yellow influences perception
true greyjudged grey Hansen et al. 2006
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So what about prior beliefs in the brain?
MT
LIP• This is still under investigation!
• Some candidates have been suggested, including ‘action’ areas of the visual system
• Understanding prior beliefs in the brain might help us decide between models
SC
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Perceptual decision making…
DecisionShort- vs
Long-termgain
Context
Risk
Information gathering
Prior Beliefs
Value
![Page 41: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/41.jpg)
Information gathering
Is Wally on the right or the left hand side of the beach?
![Page 42: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/42.jpg)
Adding prior information
He’s definitely next to one of the boats…
![Page 43: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/43.jpg)
Next we consider the value of different options
DecisionShort- vs
Long-termgain
Context
Risk
Information gathering
Prior Beliefs
Value
![Page 44: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/44.jpg)
Any questions…?
![Page 45: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/45.jpg)
A candidate brain area…
1 target
2 targets
4 targets
DimPossible Targets Select
8 targets
Accumulation of evidence over time is lower with more targets to choose from (ie more uncertainty as to probability of target location)
SC a
ctivi
ty a
t ‘D
IM’
TimeBasso and Wurtz 1998
Let’s ‘dim’ the lights…
![Page 46: What is a decision, and what’s going on in the brain? Elisabeth Rounis and Louise Whiteley The mathematical brain:](https://reader030.fdocuments.us/reader030/viewer/2022032607/56649ed05503460f94bddcb8/html5/thumbnails/46.jpg)
A candidate brain area…
Accumulation of evidence over time is lower with more targets to choose from (ie more uncertainty as to probability of target location)
SC a
ctivi
ty a
t ‘D
IM’
TimeBasso and Wurtz 1998
Let’s ‘dim’ the lights…
MT
LIP
SC