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ANC Workshop: Simon Lyons and Anthony Cruickshank, Chair: Botond Cseke

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What
  • ANC Workshop Talk
When Nov 26, 2013
from 11:00 AM to 12:00 PM
Where IF 4.31/4.33
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Simon Lyons

Series Expansions and Stochastic Differential Equations

The first part of this talk will be a short introduction to the theory of stochastic differential equations. In the second part of the talk, I'll discuss an approximation that I developed in collaboration with Amos Storkey and Simo Sarkka. The talk will be as non-technical as I can make it: I'll try to make most of my points using pictures rather than equations.

Key words: Diffusion, Fokker-Planck equation, Brownian motion, Langevin equation.

 

Anthony Cruickshank

The existence within the mammalian brain of both goal-directed and habitual decision making systems has been recognised from early studies in psychology and neuroscience. Goal-directed action selection is performed by looking ahead through an internal representation of the environment to determine the optimal outcome. Habitual action selection uses a stimulus-response mechanism based on the expected value of actions learnt after extensive experience. The goal-directed decision system is thus highly adaptable, but this flexibility comes at a cost in both the time and cognitive resources. The habitual system does not incur this cost as actions are selected based on their cached expected value. This produces actions swiftly but can lead to inflexible behaviour when the environment changes. The nature of how these two systems interact is unclear. We propose a sequential decision model with several novel features that extends previous work and show that this model successfully replicates the behaviour of rodents in devaluation and contingency degradation tasks. We then propose further extensions to the model that may address a number of outstanding questions on decision making.