The fronto-temporal cortex has increased subcortical connectivity in utero and plasticity in adulthood

The adult cerebral cortex is a heterogenous structure with prominent functional differences between regions. However, less is known about how different regions acquire and maintain their functionality. Here, we leveraged connectomes and brain transcriptomes from human foetal and adult brains of both sexes to investigate early and late differences between cortical regions. We show that at 24 post-gestational weeks fronto-temporal regions are disproportionally connected to subcortical regions, highlighting their role in early integrative cortical-subcortical communication. In adulthood, fronto-temporal cortex has lower myelin content and exhibits lower expression of marker genes of perineuronal nets, while showing higher expression of undifferentiated progenitor cells markers. These results suggest that in the adult brain the function of fronto-temporal regions reflects a heightened state of plasticity, possibly to maximise flexible neural responses. In contrast, the function of parietal and occipital regions aligns with decreased plasticity needed to support stable neural dynamics. Linking physiology to pathology, we show that the greater plasticity of the fronto-temporal cortex is coupled to higher oncogenic vulnerability - frontal and temporal regions have greater incidence of gliomas and express higher levels of genes upregulated in glioma even in the absence of malignancy, suggesting a greater glioma-like normative expression state. Together, these findings highlight the divergent patterns of connectivity in utero, and plasticity in adulthood between cortical regions and provide a framework in which functional differences across cortical regions reflect differences in connectivity and plasticity.

Significance statement Here we leveraged foetal neuroimaging and adult brain transcriptomes to investigate early and late differences between cortical regions. We present new evidence that already at mid-prenatal development, the fronto-temporal lobes are disproportionally connected to subcortical regions, potentially reflecting an early route to their establishment as integrative cortical centres. In adulthood, the fronto-temporal cortex had increased plasticity of its connections and cellular state which was coupled to greater oncogenic vulnerability. The combination of increased early connectivity and long-term plasticity might serve to maximise flexible neural representations and support the domain-general function of fronto-temporal regions.