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.