McMahon, J. T. | Search bioRxiv

bioRxiv2026

A caudate-centered network for alexithymia derived from patients with brain tumors

Alexithymia is a trait characterized by impaired emotional awareness. Previous accounts examining the neurobiological underpinnings of this trait have centered on a variety of structures, and alexithymia-causing lesions occur in disparate locations. We use lesion network mapping to derive a neural circuit for alexithymia. In a neurosurgical cohort of 45 patients with gliomas (19 female; aged 18-75 years), we compute each lesion's connectivity to the rest of the brain using a normative connectome (n = 1,000) and relate these connectivity maps to preoperative Toronto Alexithymia Scale scores using permutation testing. Lesions associated with higher alexithymia are connected to a common network that includes the bilateral caudate heads (right greater than left) and the anterior cingulate cortex, peaking in the right caudate head (family-wise error-corrected p < 0.05). The network converges with coordinates from an independent meta-analysis of gray matter volume in alexithymia (13 of 14 coordinates positive; p = 0.0004). Of the three subscales, difficulty identifying feelings localized to this network. Within the striatum, the network spans the executive and limbic subdivisions. These findings suggest a caudate-centered circuit, at the interface of affective and executive systems, that unifies disparate lesion locations.

neuroscience↗

bioRxiv2026

A network for self-transcendence derived from patients with brain lesions

Self-transcendence, the reorientation of experience away from the self toward others, nature, or broader meaning, is a fundamental dimension of human psychology, yet its causal neural architecture remains poorly understood. Here we applied lesion network mapping to 88 neurosurgical patients with pre- and post-operative assessments of trait self-transcendence to identify the distributed brain network whose disruption alters this capacity. The resulting network showed significant spatial correspondence with the default mode network and, at a finer parcellation level, with frontoparietal control subnetworks. Leave-one-out analyses identified posterior midline regions as the most stable correlates of increased self-transcendence following brain lesions. Independent validation against fMRI meta-analyses of self-referential processing, compassion, and ketamine administration, alongside a neuromodulation target previously shown to modulate the sense of self, converged on a consistent model. These findings provide causal evidence for a network architecture in which posterior midline hubs constrain, and brainstem and anterior midline regions facilitate, self-transcendent experience.

neuroscience↗