Patrick Simen

Research Fellow
Center for the Study of Brain, Mind and Behavior
and
Program in Applied and Computational Mathematics

Princeton University
209 Fine Hall
Washington Rd.
Princeton, NJ 08544-1000

Phone: (609) 258-6155
Fax: (609) 258-1367
psimen@math.princeton.edu

I am a postdoctoral research fellow at the Center for the Study of Brain, Mind and Behavior and the Program in Applied and Computational Mathematics at Princeton University, working with Prof. Jonathan Cohen in Psychology and Prof. Phil Holmes in Applied Mathematics. The focus of our research is on the role of reward and cost monitoring on human and animal performance in decision making tasks, and on the possible mediation of reward monitoring by orbitofrontal cortex and cost monitoring by anterior cingulate cortex. My work involves computational and mathematical modeling in conjunction with empirical studies of human decision-making.

I recently received a Ph.D. in Computer Science and Engineering from the Intelligent Systems program of the University of Michigan. There I worked with Prof. Thad Polk in the U. of M. Psychology Dept, and in collaboration with Prof. Rick Lewis in Psychology at U. of M. and Prof. Eric Freedman in Psychology at U. of M. Flint, where we used recurrent neural networks to create computational models of human problem solving in the Tower of London task (a psychological task much like the disk-stacking Tower of Hanoi task). The Tower of London task is a good task for identifying problem-solving impairment in patients who have suffered damage to the prefrontal cortex and in patients with Parkinson's disease, which is primarily a disease of the basal ganglia. The cognitive function of these brain areas and their relationship to each other were our primary concern. Our hypothesis has been that they are critical for the representation and processing of symbolic information by the brain, as well as for the coding and manipulation of representations of time. In particular, we have hypothesized that dorsolateral prefrontal cortex is selectively responsible for the representation of subgoals.

PhD Thesis

Neural mechanisms for control in complex cognition
2004, Computer Science and Engineering, University of Michigan.

Publications

  1. Rapid decision threshold modulation by reward rate in a neural network (.pdf), Simen P, Cohen JD, Holmes P, Neural Networks, 2006, 19:1013-1026.
  2. A computational account of latency impairments in problem solving by Parkinson's patients (.pdf), Simen P, Polk T, Lewis R, Freedman E, Proceedings of the International Conference on Cognitive Modeling, 2004, 273-279.
  3. Columnar timing mechanisms in neural models of problem solving (.pdf), Simen P, Freedman E, Lewis R, Polk T, 2003 Computer Science and Engineering technical report CSE-TR-481-03.
  4. Universal Computation by Networks of Model Cortical Columns (.pdf), Simen P, Polk T, Lewis R, Freedman E, Proceedings of the International Joint Conference on Neural Networks, July 2003, 230-235.
  5. A Computational Approach to Control in Complex Cognition (.pdf), Polk T, Simen P, Lewis R, Freedman E, Cognitive Brain Research 1(2002):71-83.
  6. A Recurrent Neural Network Model of Goal Management (.pdf), Simen P, Polk T, Lewis R, Freedman E, Proceedings of the International Conference on Computational Intelligence and Neuroscience, 2002, 504-508.

Posters

  1. A diffusion-based neural network model of interval timing and temporal discounting Simen P, Cohen J. D., poster presented at the 2007 Society for Neuroscience Conference.
  2. Explicit melioration by a simple neural network Simen P, Cohen J. D., poster presented at the 2007 Computational Cognitive Neuroscience/Dynamical Neuroscience Conference.
  3. Melioration by a diffusion model with response threshold adaptation Simen P, Holmes P, Cohen J, poster presented at the 2006 Society for Neuroeconomics conference.
  4. Threshold adaptation in decision making Simen P, Holmes P, Cohen J. D., poster presented at the 2005 Society for Neuroscience conference.
  5. A model of threshold adaptation in perceptual decision making Simen P, Holmes, P, Cohen, J. D., poster presented at the 2005 Cognitive Neuroscience Society meeting.
  6. Sequence learning in model frontostriatal circuits Simen P, Freedman E, Lewis R, Polk T, poster presented at the 2003 Society for Neuroscience meeting.
  7. Modeling Executive Control, Problem-Solving and Sequencing in Neural Networks (.pdf) Simen P, Polk T, Lewis R, Freedman E, poster presented at the 2003 annual meeting of the Cognitive Neuroscience Society.
  8. An Explicit Model of Executive Control in Complex Cognition (.pdf), Simen P, Polk T, Lewis R, Freedman E, poster presented at the 2002 annual meeting of the Society for Neuroscience.
  9. A Recurrent Neural Network Model of Executive Control in the Tower of London Task (.pdf), Simen P, Polk T, Lewis R, Freedman E, poster presented at the 2002 annual meeting of the Cognitive Neuroscience Society.

Curriculum Vitae