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Identification of brain regions important in behavioural adaption to reward
Image: Diederen et al., 2016
Every day we make many decisions: where to go for lunch or which road to take home to avoid traffic. In order to pick the best, we have to learn what to expect from each option. Learning what to expect is difficult since the outcomes of our choices tend to vary from time to time. The quality of lunch served in a restaurant may for example vary slightly from day to day depending on the freshness of the ingredients. However, a big change in food quality could result from the restaurant having hired a new chef. Therefore, we need to learn what kind of variability is small enough to ignore in order that we may notice when the food in a café suddenly becomes unacceptably bad or exceptionally good. In other words, we need to be able to update our predictions when the outcome changes much more than expected.
Neuroscience has long recognised that we learn from our mistakes. The brain is sensitive to surprising outcomes - so-called prediction errors - and uses these to drive the learning process. But the world is an unreliable place and, if we changed our beliefs in response to every unpredicted outcome we would probably function very poorly. One of the real challenges facing us is knowing when we should take notice of surprises ("prediction errors") and when we should just ignore them and put them down to chance. Indeed, it has been suggested that certain symptoms of mental illness may arise because of a difficulty in successfully achieving this balance - either failing to adjust our learning when we really should or else adjusting it too readily and so developing an unrealistic view of the world.
Reference: Adaptive Prediction Error Coding in the Human Midbrain and Striatum Facilitates Behavioral Adaptation and Learning Efficiency Diederen, Kelly M.J. et al. 2016 Neuron
Posted on 13/05/2016
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