Decision making mechanisms in the brain

A combination of approaches including functional neuroimaging, neurophysiology, and theoretical physics, provides evidence that decisions in the cerebral cortex are taken by attractor networks that are biased by the evidence for the decision [1-2]. Integrate-and-fire neuronal networks show that decision-making is inherently probabilistic because of noise caused by the random firing times of neurons in the brain (for a given mean rate). It is shown that confidence in a decision is an emergent property of the decision-making process, and human fMRI investigations that test this have been described [1-5]. Decisions can be in part predicted from the noise in the neuronal firing before the decision cues are applied. The attractor network architecture for decision-making is similar to that involved in short-term memory and attention [6], and instabilities in such networks in brain regions such as the prefrontal and temporal cortex are hypothesized to be involved in schizophrenia [6].