To investigate the relationship between emotion processing and resting state-functional connectivity (RS-FC) in healthy controls (HC) and patients with frontotemporal lobar degeneration (FTLD).

Nonverbal communication is a crucial aspect of interpersonal relationships and defective emotion recognition can lead to altered social interactions. Altered RS-FC associated with emotion processing in FTLD patients is yet to be determined.

We recruited 80 FTLD (26 bvFTD, 10 PSP, 12 PPA, and 32 ALS) and 65 HC. Participants underwent resting-state functional MRI (RS-fMRI) and a comprehensive neuropsychological assessment, including the Comprehensive Affect Testing System (CATS). RS-fMRI brain networks of interest were identified using an independent component analysis and correlation models were performed in both groups between each emotion construct and the RS-FC changes.

A high performance at the emotion naming was related in HC with decreased RS-FC of the right inferior temporal gyrus within the right frontoparietal-network; and in FTLD patients with increased RS-FC of the frontal regions within salience, frontoparietal and executive-control networks. Furthermore, a high performance at the emotion differentiation was related in HC with decreased RS-FC of the right middle temporal gyrus within the salience-network; and in FTLD patients with increased RS-FC of the left inferior and medial-orbitofrontal gyri, and right thalamus within the subcortical-network. Finally, a high performance at the emotion matching was related in both HC and FTLD groups with increased RS-FC of precuneus and vermis within the visual-network, and with further increased RS-FC of bilateral lingual, middle temporal and calcarine gyri in FTLD group only.