Surprise response as a probe for compressed memory states
Fig 4
Multi-subject comparison of the NOC and IB models.
(a) The mean normalized AUC of each subject is plotted as a function of the running probability (RP) of the opposite tone. The RP on each trial is defined as p = n/N, where n is the number of occurrences of the opposite tone (with respect to the current tone) in the preceding N tones in the sequence, and N is the fitted model parameter. R2 = 0.498, 409 data points, error DOF = 407, F-statistic vs. constant model: 404, p-value = 7.28 × 10−63. Inset: The mean responses across all subjects as a function of the RP, calculated using the data presented in (a). The error bars indicate the SEM. (b) The mean normalized AUC of each subject is plotted as a function of the IB surprise. R2 = 0.471, 445 data points, error DOF = 443, F-statistic vs. constant model: 394, p-value = 0. Inset: The mean responses across all subjects as a function of the IB surprise, calculated using the data presented in (b). The error bars indicate the SEM. (c) Each pair of bars shows the estimated effective capacity (in bits) for the optimal NOC model (blue bars) and for the optimal IB model (red bars) for each subject. The effective capacity for the NOC model is defined as the number of bits required to represent all possible values of occurrences from 0 to N; i.e., log2(N + 1). For the IB model the estimated capacity is defined as I(X; M); i.e., the mutual information between the past variable X = [0..N] and the representation variable M defined by IB. The colored map under each pair of columns shows the IB R2 map of that subject (as in Fig 3c).