Fig. 5: Relationship between learning stage and the geometry of neural representation. | Nature Communications

Fig. 5: Relationship between learning stage and the geometry of neural representation.

From: Efficient and dynamic neural geometry of value and modality encoding in the primate putamen for value-guided behavior

Fig. 5

A Behavioral analysis scheme for categorizing trials into early and late learning stages within each block. Reaction times (RT) for good (green) and bad (red) values are plotted across the trials. Shaded areas indicate early (light gray) and late (dark gray) learning stages. Each data point is based on a sample size ranging from 86 to 271 for the ‘Good → Bad’ condition, and from 73 to 271 for the ‘Bad → Good’ condition. The solid circles represent the mean reaction time across trials, and the error bars indicate the standard error of the mean (SEM) at each trial. B Box plots comparing the reaction times (RT) for good and bad values, as well as the RT difference (bad - good), between the early and late learning stages. A right-tailed Wilcoxon signed-rank test was conducted for the good value (p  =  6.497 × 10−25), a left-tailed Wilcoxon signed-rank test for the bad value (p  =  1.94 × 10−31), and a two-tailed Wilcoxon signed-rank test for the RT difference (p  =  3.709 × 10−44) (n = 997 trials for both early and late). In box plots, the center line indicates the median, box edges show the 25th and 75th percentiles, and whiskers extend to values within 1.5 times the interquartile range (IQR). Outliers beyond this range are shown as individual points. C Decoding results (SVM and CCGP) for modality and value in the early learning stage across three phases (right-tailed z-test). D Traditional decoding (SVM) and CCGP in the early learning stage are plotted as a function of time. Horizontal bars represent periods of decoding performance above the results of the null model (right-tailed z-test, p < 0.05). E Decoding results (SVM and CCGP) for modality and value in the late learning stage across three phases (right-tailed z-test). F Identical to (D) but for the late learning stage (right-tailed z-test, p < 0.05). G Principal component analysis (PCA) plot illustrating the geometry of bimodal value neurons over time in the early learning stage. H The same format is used in (G), but for the late learning stage. *p < 0.05, **p < 0.005, ***p < 0.0005, n.s. not significant.

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