Objective:

To begin expanding on previous lesion network mapping of delusions.

Background:

Previous lesion network mapping specific to misidentification delusions (Darby et al. 2017) supports the hypothesis that a brain circuit paradigm may advance the neural understanding of delusions generally.

Design/Methods:

To begin, 17 lesions causing a variety of delusions were identified and analyzed to identify patterns of connectivity to patient brain lesions. Functional connectivity with each lesion was computed utilizing a large cohort of healthy control resting state scans (N = 1000). Sensitivity and specificity testing were combined to generate a conjunction map of lesion connectivity patterns associated with delusions in our sample. 

Results:

15 of our 17 lesions were not included in the primary case report sample for the Darby, 2017 study. This is because we did not restrict to misidentification delusions. Of the 17 thresholded lesion networks, 14 (82%) positively overlap at the supramarginal gyrus and 13 (76%) positively overlap at the anterior division of the cingulate gyrus in the sensitivity map. In the specificity map there were peak statistical association with positive functional connectivity between lesions and the posterior lobe of the cerebellum (ₚ🇫we<4.7). The conjunction map functional connectivity with lesions displayed two regions: parts of the posterior lobe of the cerebellum and caudal hypothalamus. 

Conclusions:

Delusions in our sample of case reports are associated with the functional connectivity between brain lesions and the supramarginal gyrus, which replicates the results of a previous study on brain lesions associated with misidentification delusions. (Darby et al., 2017) Additionally, results showed positive lesion connectivity with the cingulate gyrus is associated with delusions in our case report sample, differing from the Darby study but complementing it by further supporting a perspective of distinct neural networks associating with distinct categories of delusion symptoms.