Neural circuits for bias and sensitivity in decision-making Jan Lauwereyns Associate Professor,...

Neural circuits for bias and sensitivity in decision-making

Jan LauwereynsAssociate Professor, Victoria University of Wellington, New Zealand

Long-term Invitation Fellow, Japanese Society for the Promotion of Science

Visiting Scholar, Tamagawa University, Tokyo, Japan

The Perfect Grandpa

Biological needs

The drive reduction hypothesis

Think: Inclusive fitness

Think: energy, reproduction

Approach

Avoid

Biological needs


Several hours have passed since last meal

Biological needs



Increased drive (hunger)

Increased exploratory activity

Biological needs




Find food, eat it

Drive is reduced (reinforcement)


Biological needs


Find food, eat it

Drive is reduced (reinforcement)




Dopamine reward prediction(Schultz)

Executive control

• Goals, beliefs, wishes, fears…

• Related to motivational control

• Some sensory information is valuable to the individual in the sense that it may be used in the strategic (“optimal”) control of behavior

• Executive control would seek to maximize the extraction of valuable sensory information

How can executive control affect information processing?

Two general hypotheses:

• Sensitivity

– Selective improvement of

information processing

(actual perception)

• Bias:

– Selective preparation (“anticipation”)

of information processing

(virtual perception)

For example: “Reward”

Distinguishing effects of sensitivity and bias

Signal detection theory (Green & Swets)

Probability of response

LATER model (Carpenter)

Latency of response

Signal detection theory

SignalNoise

Neuronal activity

Noise

Noise

Signal +

Signal +

A different way to think about bias and sensitivity…

Scheme of the original LATER model (RHS Carpenter)

Nose Poke Paradigm:

Spatial choice, Gives us good reaction-time distributions

Target side: 4 LEDsvs. Distracter side: 0-3 LEDs

Lauwereyns & Wisnewski (2006, JEP:ABP)

Theoretical example of bias

Theoretical example of sensitivity

How does it really work?

• How does the brain incorporate reward value in the control of action?

• How does the brain incorporate reward value in the control of action?

• Studied in monkeys using saccadic eye movement tasks

with asymmetrical reward schedule

Biased Saccade Task (BST)


Target position =

unpredictable


Reward association = known


No escape!

Asymmetric position-reward mapping in “ABA” design

• Frequent reversal of blocks

Strong effect of reward value on saccade latency

• Range of 50 to 200 ms, faster on reward trials

Saccade-related brain areas (macaque monkey)

FEF: frontal eye fieldSEF: supplementary eye fieldLIP: area LIP of parietal cortexCD: caudate nucleusSNr: substantia nigra pars reticulataSC: superior colliculusClbm: cerebellumSG: brainstem saccade generators

Inputs to Striatal Medium Spiny Neuron

Smith & Bolam (1990)

Medium Spiny Neuron in Striatum

Preston, Bishop & Kitai (1980)

Single unit recording from Caudate Nucleus

L-CD neuron: AllReward

Population activity of CD neurons(with contra-bias, n=25)

Lauwereyns et al. (2002, Nature)

Weakcorrelation

Strongcorrelation

General increase

Reward leads to general increase of neural activity = bias effect; no change in d’

Lauwereyns et al. (2002, Neuron)

Data from CD

General increase:Prospective, additive

• Bias in anticipatory activity

• Linearly enhances sensory activity

General increase:Prospective, additive

• Bias in anticipatory activity

• Linearly enhances sensory activity

Response = Input + Reward Bias

Prefrontal cortex, basal ganglia

Superior colliculus

Is it all bias?

Or can we find examples of sensitivity?

Improved discrimination

Reward leads to improved discrimination of neural activity = change in d’, no bias effect

Kobayashi et al. (2002, J. Neurophysiol.)

Data from DLPFC

Improved discrimination:Synergistic, multiplicative

• Sensory properties

• Non-linearly enhanced by reward

Improved discrimination:Synergistic, multiplicative

• Sensory properties

• Non-linearly enhanced by reward

Response = Input * Reward Gain

Prefrontal cortex, parietal cortex

Superior colliculus

Never the twain shall meet?

Improved discrimination & General increase

Combination of both mechanisms

• Seen in all areas• Loops between FC, BG and SC• But most common in Superior Colliculus

0

2

4

6

8

10

12

Cue RF Cue nonRF

Neu

ron

al A

ctiv

ity

No reward

Reward



Response = (Input * Reward Gain) + Reward Bias

On toward the oculomotor plant

Dopamine

DopamineExcitation

DopamineExcitation

Disinhibition

Synergistic,multiplicative

DopamineExcitation

DisinhibitionSensitivity

Prospective, additive


DopamineExcitation


Bias



DopamineExcitation


Bias

Thalamus

Back to LPFC,On to posterior cortices,Back to CD

…

…

Only prefrontal cortex?Evolution of the dopamine system: toward innervation of more and more cortex

Nieoullon, 2002

Effects of methamphetamine(METH) (speed)



DopamineExcitation

DisinhibitionD1 > D2

D2 > D1

Thalamus

Back to LPFC,On to posterior cortices,Back to CD

Neural circuits for bias and sensitivity in decision-making Jan Lauwereyns Associate Professor,...

Documents

Transcript of Neural circuits for bias and sensitivity in decision-making Jan Lauwereyns Associate Professor,...