A Measure of Information Available for Prediction

Mutual information between the brain state and the external world state represents the 6 amount of information stored in the brain that is associated with the external world. On the other 7 hand, surprise of sensory input indicates the unpredictability of the current input. In other words, 8 this is a measure of prediction capability, and an upper bound of surprise is known as free energy. 9 According to the free-energy principle (FEP), the brain continues to minimize free energy to perceive 10 the external world. For animals to survive, prediction capability is considered more important than 11 just memorizing information. In this study, the fact that free energy represents a gap between the 12 amount of information stored in the brain and that available for prediction is established, where the 13 latter will be referred to as predictive information as an analogy with Bialek’s predictive information. 14 This concept involves the FEP, the infomax principle, and the predictive information theory, and will 15 be a useful measure to quantify the amount of information available for prediction. 16