Brain circuits for the representation of subjective reward value

Successful interaction with the external world requires choosing appropriate actions in the context of available choices. Such decisions require the evaluation of the reward magnitude, or value, associated with each potential action. Delineating the neural circuits involved in this process remains an important goal in systems neuroscience. However, little is known about the neural circuits that compute, or represent, low level primary reward signals. We have combined quantitative psychophysical measures of subjective reward magnitude elicited by rewarding electrical brain stimulation, fMRI as a readout of whole-brain neural activity, and local inactivation of brain structures, to identify the neural representation of subjective reward magnitude. We find that multiple brain regions are activated by rewarding brain stimulation, but only two brain regions, the nucleus accumbens and the central and basolateral nucleus of the amygdala, exhibit patterns of activity levels that track the reward magnitude measured psychophysically, suggesting a role in the neural representation of reward magnitude. Furthermore, pharmacological silencing of the ventral tegmental area (VTA) disrupts reward-tracking behavior and increases stimulus-dependent activity in the nucleus accumbens and amygdala. Together these data suggest that ascending and descending pathways combine to produce a signal that ultimately guides behavior and is subject to modulation by VTA inputs.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Brain and Cognitive Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2011

Author dc:creator

• Fiallos, Ana Marcia

Advisor dc:contributor.advisor

• Alan Pradip Jasanoff.

• Brain and Cognitive Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/62716

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/62716