April 4 lecture note

April 4 lecture note - 03-04-2007 1 Reward, learning and...

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Unformatted text preview: 03-04-2007 1 Reward, learning and the brain John P. John P. ODoherty Doherty Lecture for Bi133 Lecture for Bi133 April 4 April 4 th th 2007 2007 What is a reward? What is a reward? A reward is anything that an animal will work to attain Rewards are motivating - elicit approach and consummatory behavior The reinforcing properties of rewards depend on the animals internal motivational state Rewards result in goal-directed instrumental responding Some rewards are primary reinforcers i.e. have innate value and have not acquired their reinforcing properties through learning Examples of primary rewards include: tastes, odors, sex, grooming, social affiliation (see Rolls, 1999) In humans, rewards have an associated subjective state 03-04-2007 2 Early studies of reward behavior Reversal Learning 12 13 11 10 14 Somatosensory Gustatory Auditory Visual Olfactory TA 22 TE 21 Insula Transverse view of orbitofrontal cortex Pyriform Lateral sagittal view Coronal view through anterior temporal lobes Orbitofrontal cortex Iversen and Mishkin (1970) Lesions of monkey orbitofrontal cortex impairments at reversal learning 03-04-2007 3 Effects of OFC and DLPFC lesions on reward-related reversal learning in humans Sorry! You have lost 250 pounds Total amount won in numerical form Feedback following stimulus selection Total amount won in graphical form Feedback available during task performance Hornak et al., Journal of Cognitive Neuroscience 2004 Effects of OFC and DLPFC lesions on reward-related reversal learning in humans PATIENTS 6 patients with bilateral OFC lesions BK BK JT JT 5 patients with unilateral OFC lesions 11 patients with unilateral DLPFC lesions SC SC 5 patients with mixed unilateral lesions (OFC+DLPFC) HR HR 3 patients with medial PFC lesions FF FF 03-04-2007 4-3000-2000-1000 1000 2000 3000 4000 5000 1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81 86 91 96 Trial number Cumulative total () BL OFC UL OFC Medial PFC DLPFC - attended DLPFC - failed to attend Normal control subjects RESULTS RESULTS Effects of OFC and DLPFC lesions on reward-related reversal learning in humans Hornak, ODoherty, et al. , Journal of Cognitive Neuroscience, 2004 Bechara et al., 1994 03-04-2007 5 1/ Representing Stimulus 1/ Representing Stimulus-reward value reward value 2/ Encoding Predictive reward value 2/ Encoding Predictive reward value 3/ Learning predictive value representation 3/ Learning predictive value representation 4/ Mediating Action Selection for reward 4/ Mediating Action Selection for reward Delineate neural systems involved in: Reward and Motivation 1/ Representing Stimulus 1/ Representing Stimulus-reward value reward value 2/ Encoding Predictive reward value 2/ Encoding Predictive reward value 3/ Learning predictive value representations 3/ Learning predictive value representations 4/ Mediating Action Selection for reward 4/ Mediating Action Selection for reward Reward circuits in the brain 03-04-2007 6 12 13 11 10 14 Somatosensory...
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April 4 lecture note - 03-04-2007 1 Reward, learning and...

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