Fig. 2: Stimulation effects on acceptance probability and computational mechanisms.
From: Direct stimulation of anterior insula and ventromedial prefrontal cortex disrupts economic choices
a Spatial gradient of the effect of intracranial electrical stimulation (iES) on acceptance probability along the anteroposterior (y-axis) and ventrodorsal (z-axis) directions in the anterior insula (aIns; top) and ventromedial prefrontal cortex (vmPFC; bottom). Gray arrows indicate the gradient direction. b Clusters obtained by k-means clustering are plotted along the anteroposterior and ventrodorsal axes. In the aIns, squares represent the dorsal aIns (daIns) and diamonds represent the ventral aIns (vaIns), as delineated by Destrieux’s parcellation scheme36. This is to compare statistically defined clusters (depicted in this figure) with anatomically defined subregions (Fig. 3). Additionally, to prevent any confusion with the anatomical terminology referring to the anterior and posterior portions of the insula, we renamed the two statistically defined clusters in this region as dorsal and ventral, respectively. c Effects of iES on clusters. d Effects of iES on participants’ sensitivity to potential losses (\({k}_{l}\)). In panels (c) and (d), dots respectively represent individual differences in acceptance probability and model weight (i.e., posterior parameter) \({k}_{l}\) between trials with and without iES for each stimulation site. Gray lines connect the stimulation sites of the same participant. Bars and error bars represent mean and SEM, respectively, across stimulation sites. Significant interactions between stimulation condition and statistically defined clusters were found for iES effect (c; aIns: F1,72 = 11.6, p = 0.001; vmPFC: F1,28 = 10.1, p = 0.004) and sensitivity to potential losses \({k}_{l}\) (d; aIns: F1,72 = 15.3, p < 0.001; vmPFC: F1,28 = 13.6, p < 0.001) using a linear mixed-effects model with participants (aIns: n = 13; vmPFC: n = 9) and stimulation sites (aIns: n = 38; vmPFC: n = 16) as random effects. In the aIns, post-hoc analyses reveal that iES decreased risk-taking (c; F1,72 = 6.7, p = 0.012) and increased \({k}_{l}\) (d; F1,72 = 7.6, p = 0.008) when applied to the ventral part (dark pink; n = 15), while iES increased risk-taking (c; F1,72 = 5.4, p = 0.023) and decreased \({k}_{l}\) (d; F1,72 = 6.3, p = 0.014) when applied to its dorsal part (light pink; n = 23). In the vmPFC, post-hoc analyses reveal that iES increased risk-taking (c; F1,28 = 6.5, p = 0.016) and decreased \({k}_{l}\) (d; F1,28 = 8.9, p = 0.006) when applied to the ventral part (dark green; n = 9), whereas iES increased \({k}_{l}\) (d; F1,28 = 5.2, p = 0.030) when applied to the dorsal part (light green; n = 7). Stars between bars indicate significant interactions. Stars above a single bar indicate significant post-hoc analyses (adjusted using the Benjamini-Hochberg procedure). + p = 0.056, *p < 0.05, **p < 0.01, ***p < 0.001.
