Figure 2.

Illustration of the principles of Bayesian inference in neuronal coding. Top-down pre-conceived notions about a sound (illustrated as a sound trace surrounded by a blue haze) are combined with noisy information from the periphery (illustrated as a noisy sound trace entering the ear). Bayes theorem (in the box) combines the pre-conceived notions with the noisy sensory information to recover the original signal (here represented as the posterior probability or the actual percept.