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Coding of rewarded tasks by ventral ...

Tindell, Amy Joy.

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Coding of rewarded tasks by ventral pallidum neurons: Learning, hedonics, and incentive value.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Coding of rewarded tasks by ventral pallidum neurons: Learning, hedonics, and incentive value./
Author:	Tindell, Amy Joy.
Description:	211 p.
Notes:	Source: Dissertation Abstracts International, Volume: 66-09, Section: B, page: 4666.
Contained By:	Dissertation Abstracts International66-09B.
Subject:	Biology, Neuroscience. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3186772
ISBN:	054230290X

Coding of rewarded tasks by ventral pallidum neurons: Learning, hedonics, and incentive value.
Tindell, Amy Joy.

Coding of rewarded tasks by ventral pallidum neurons: Learning, hedonics, and incentive value. - 211 p.

Source: Dissertation Abstracts International, Volume: 66-09, Section: B, page: 4666.

Thesis (Ph.D.)--University of Michigan, 2005.

The ventral pallidum (VP) is a brain structure essential for reward learning and motivation. However, little is known about how VP neurons actually process reward information. In these studies, neural activity in the VP was recorded in freely moving rats as they learned a Pavlovian task in which specific stimuli predicted a reward. The first study demonstrated that VP neuronal firing encodes learning and reward by increasing the number of neurons that respond to reward-predicting stimuli, and by varying the speed at these neurons fire. In subsequent studies, I asked whether VP firing to stimuli during the task reflect purely predictive information or also motivational reward ("incentive salience") properties of the stimuli. I induced physiological shifts in rats' motivational state after learning by sensitizing rats to amphetamine (which enhances incentive motivation for rewards) or depleting rats of sodium (which selectively enhances salt taste reward). Changes in VP firing following these motivational shifts allowed us to compare directly prediction models versus motivational incentive salience models. After amphetamine sensitization, VP neurons immediately increased their response to the predictive stimulus associated with a relevant reward, indicating coding of motivational incentive salience. Our novel computational Profile Analysis technique showed a shift in VP firing toward the stimulus with highest motivational incentive salience. These shifts in coding occurred without new learning about the predictive tones, again indicating motivational value influenced by physiological states. My last experiments showed that VP firing codes hedonic impact of rewards themselves, in addition to incentive motivational value of learned stimuli that predict reward. After physiological sodium depletion caused the taste of concentrated triple-seawater salt, which normally is 'disliked', to become strongly 'liked', VP neurons increased firing to the taste in a manner that coded hedonic reward value. My results demonstrate that VP neurons code the motivational value of cues and rewards, tracking that value through shifts in homeostasis, and extracting information about learned stimuli that reflects the current motivational value of the rewards they predict. These data emphasize the ability of VP neurons to multiplex information about reward prediction and motivation by integrating learned predictive associations and dynamic physiological states. My studies reveal important roles for VP neurons in coding normal reward learning and motivation, and suggest that VP dysfunction may be implicated in human motivational disorders including drug addiction and eating disorders.

ISBN: 054230290XSubjects--Topical Terms:

1017680
Biology, Neuroscience.

Coding of rewarded tasks by ventral pallidum neurons: Learning, hedonics, and incentive value.
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100 1 $a Tindell, Amy Joy. $3 1905148
245 1 0 $a Coding of rewarded tasks by ventral pallidum neurons: Learning, hedonics, and incentive value.
300 $a 211 p.
500 $a Source: Dissertation Abstracts International, Volume: 66-09, Section: B, page: 4666.
500 $a Co-Chairs: J. Wayne Aldridge; Kent C. Berridge.
502 $a Thesis (Ph.D.)--University of Michigan, 2005.
520 $a The ventral pallidum (VP) is a brain structure essential for reward learning and motivation. However, little is known about how VP neurons actually process reward information. In these studies, neural activity in the VP was recorded in freely moving rats as they learned a Pavlovian task in which specific stimuli predicted a reward. The first study demonstrated that VP neuronal firing encodes learning and reward by increasing the number of neurons that respond to reward-predicting stimuli, and by varying the speed at these neurons fire. In subsequent studies, I asked whether VP firing to stimuli during the task reflect purely predictive information or also motivational reward ("incentive salience") properties of the stimuli. I induced physiological shifts in rats' motivational state after learning by sensitizing rats to amphetamine (which enhances incentive motivation for rewards) or depleting rats of sodium (which selectively enhances salt taste reward). Changes in VP firing following these motivational shifts allowed us to compare directly prediction models versus motivational incentive salience models. After amphetamine sensitization, VP neurons immediately increased their response to the predictive stimulus associated with a relevant reward, indicating coding of motivational incentive salience. Our novel computational Profile Analysis technique showed a shift in VP firing toward the stimulus with highest motivational incentive salience. These shifts in coding occurred without new learning about the predictive tones, again indicating motivational value influenced by physiological states. My last experiments showed that VP firing codes hedonic impact of rewards themselves, in addition to incentive motivational value of learned stimuli that predict reward. After physiological sodium depletion caused the taste of concentrated triple-seawater salt, which normally is 'disliked', to become strongly 'liked', VP neurons increased firing to the taste in a manner that coded hedonic reward value. My results demonstrate that VP neurons code the motivational value of cues and rewards, tracking that value through shifts in homeostasis, and extracting information about learned stimuli that reflects the current motivational value of the rewards they predict. These data emphasize the ability of VP neurons to multiplex information about reward prediction and motivation by integrating learned predictive associations and dynamic physiological states. My studies reveal important roles for VP neurons in coding normal reward learning and motivation, and suggest that VP dysfunction may be implicated in human motivational disorders including drug addiction and eating disorders.
590 $a School code: 0127.
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650 4 $a Psychology, Psychobiology. $3 1017821
650 4 $a Psychology, Physiological. $3 1017869
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710 2 0 $a University of Michigan. $3 777416
773 0 $t Dissertation Abstracts International $g 66-09B.
790 1 0 $a Aldridge, J. Wayne, $e advisor
790 1 0 $a Berridge, Kent C., $e advisor
790 $a 0127
791 $a Ph.D.
792 $a 2005
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