The role of dopamine neurons in reward processing is well-established, as is the observation of reward-related responses in the striatum, a region to which these midbrain dopamine neurons project. The reward-prediction error signals generated in the midbrain may play a role in the striatum in learning, as they help to shape expectations about future events based on prior experiences. The goal of the current experiment was to use principles of striatal function in order to optimize learning in an arithmetic domain. We created a training program that we believed would lead to increased arithmetic fluency by maximally engaging the striatum, through the use of contingent feedback, uncertainty regarding performance, and incentives for correct responses. Both experimental and control participants, who completed training focusing on arithmetic calculation and digit-entry respectively, showed improvement on a task involving the addition of a double-digit and a single-digit number following training, as successful performance on the task required accurate computations and entry of the solution within a narrow response window. We conducted functional magnetic resonance imaging before and after training while participants performed this task, in order to examine the effect of feedback on activity in the caudate nucleus and to determine if learning signals generated by the striatum during arithmetic training are able to modify quantity representations in parietal cortex. Results indicated activation of both the caudate nucleus and the hIPS region. Activation of the caudate nucleus replicated previous work, as it showed the prototypical pattern of activity that distinguished between positive and negative feedback. Activation of the hIPS region was not
surprising, given the focus on arithmetic calculation, but this region also exhibited feedback-sensitive activation that differed between sessions and groups, possibly indicating the common influence of a reinforcement learning system.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-04082010-121607 |
| Date | 08 June 2010 |
| Creators | Ponting, Andrea |
| Contributors | Beatriz Luna, Julie Fiez, Christian Schunn |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-04082010-121607/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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