PMC

NComp represents non-symbolic comparison, NAdd non-symbolic approximate addition, NNLE non-symbolic number-line estimation, SComp symbolic comparison, SAdd symbolic approximate addition, and SNLE symbolic number-line estimation. For number-line estimation tasks, percent absolute errors were used as an accuracy measure. Correlation coefficients on the upper diagonal were computed using data after removing outliers based on arithmetic scores (n = 93), whereas those on the lower diagonal were from data with outlier exclusion by symbolic arithmetic PAEs (n = 87). * indicates p < .05.

Joint rank and symbolic distance coding. (A,B) Example post-stimulus time histograms for two recordings with activity during choice trials sorted by joint rank. (C) Recordings (n = 142) sorted by preferred joint rank based on z-scored firing rate. (D) Estimated joint rank using an optimal linear estimator. Dotted lines are 95% confidence intervals for all trials based on 10,000 bootstrap iterations. (E,F) Example post-stimulus time histograms for two recordings sorted by symbolic distance (different recording sessions than A,B) (G) Recordings sorted by preferred symbolic distance. (H) OLE estimated symbolic distance with bootstrap estimates of 95% confidence interval.

Same‐number and different‐number correlations for symbolic (white) and nonsymbolic (black) stimuli is given in this figure. Gray bars indicate cross‐format correlations. Correlation values have been Fisher‐z transformed. Error‐bars indicate standard errors of the mean (across 33 subjects).