Fig. 3: Cortico-limbic signaling.
a Mean directionality index (DI) is shown on an inflated brain for long-range connections from each brain region to all other regions, averaged within and across participants. Green regions are biased towards efferences (i.e., sending), purple towards afferences (i.e., receiving). b Connection-level analysis: proportion of effective efferences (green), afferences (purple), and bidirectional connections (gray) grouped by DI values (legend with cutoffs in a). Top: long-range cortico-limbic connections (# total number). Note the high rate of almost unidirectional connections from limbic structures to certain neocortical areas (dark purple). Bottom: long-range connections from one neocortical to any other neocortical region. For example, the dorsofrontal cortex receives many afferences from limbic structures (purple > green), and sends many efferences to other neocortical regions (green > purple). c, d Corresponding participant-level analysis: distribution, median (full line) and IQR (dashed) of the DI by brain region, along with averages within participants (black dots) and statistical testing with post-hoc two-sided Wilcoxon signed-rank test with FDR correction across participants. e Corresponding connectograms showing the inter-regional average signaling probability (line width on the receiving end) and latency (dashed vs. full lines), colored for significant directionality (DI indicated, post-hoc two-sided Wilcoxon signed-rank test with FDR correction, p < 0.05) from hippocampus (top) or amygdala (bottom) to neocortical brain regions (# connections averaged shown). Connectograms for pairs of neocortical regions are in Supplementary Fig. 11. A graphical user interface to visualize signaling in individual connections can be downloaded at https://github.com/neuro-elab/EvM_Connectivity/releases. f Average (±95% CI) stimulation-response curves (left) at stimulation intensities 0.2–12 mA in a subset of connections and corresponding ExI for hippocampal (top) and amygdala (bottom) efferences (colored) and afferences from neocortical stimulations (gray), along with post-hoc two-sided Wilcoxon rank-sum test (no FDR correction). Source data for c–f are provided in the Source Data file.
