Figure 3.

Effect of prolonged exposure to one type of information. The $X$-axis in all plots shows the time step (e.g., time steps during a day), and the $Y$-axis shows learning trials (e.g., memory consolidation at the end of each day). (A) and (B) show the observer with chronic pain exposed to 20 time steps and 40 trials of noxious information (A), and 20 time steps and 40 trials of harmless observations (B). (C) and (D) illustrate the same observational scheme under healthy pain inference. Of note, the marginal probabilities inferred at the first- and last time step differ from the probabilities inferred in intermittent nodes for two reasons. First, due to our model architecture, the first- and final nodes only receive messages related to sensory inputs from one neighbour, while intermittent nodes receive richer sensory information from their two respective neighbours (e.g., past and future time steps), leading to increased certainty about the hidden state. Secondly, we perform batch updates at the end of one time series. In psychological terms, this corresponds to retrospective memory consolidation during sleep. With increased learning trials ($Y$-axis), however, the marginal probability of inferring pain under noxious stimulation (panels A and C) increases as a consequence of learning.