[Abstract Title]. - Society for Neuroscience

session (outside the scanner) in which they performed rapid pointing to a rectangular target for
monetary incentives. For each subject, we estimated the subject‟s own motor uncertainty for the
purpose of creating motor configurations mathematically equivalent to a single lottery. In the
second (practice) and third (fMRI) session, subjects faced both economic lottery decision tasks
and equivalent motor lottery tasks for monetary incentives revealed at the end of the experiment.
We modeled each subject‟s motor performance and economic performance using Cumulative
Prospect Theory (Tversky & Kahnrman, 1992), estimating value functions and probability
weighting functions separately for the motor and economic conditions. While no differences in
the value function between motor and economic tasks were observed, different patterns in the
probability weight function between motor and economic tasks were apparent. For the economic
task, we replicated the typical shape of the weighting function, i.e. overweighting of small
probabilities and underweighting for moderate to large probabilities. In contrast, subjects
underweighted small probabilities and overweighted large during the motor task. Our fMRI
results revealed (1) common, overlapped activations between economic and motor tasks but (2)
distinct, modality-specific encoding of probability information. The inferior parietal and the
ventrolateral premotor area, previously proposed to be involved in motor imagery, were
selectively correlated with probability in the motor task. Our results suggest that while there
might be a global decision making system independent of task modality, the emergence of
probability representation is highly modality specific.
Disclosures: S. Wu, None; M.R. Delgado, None; L.T. Maloney, None.
Poster
289. Human Decision Making
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 289.15/RR51
Topic: F.01.c. Attention
Support: NIMH grant 1R01MH076282-01
DOE grant DE-FG02-99ER6274
Function BIRN (U24-RR021992)
the John Templeton Foundation
Title: A dynamic Bayesian network analysis of functional network differences during the
auditory oddball task, related to general intelligence