Identification of central amygdala and trigeminal motor nucleus connectivity in humans: An ultra‐high field diffusion MRI study. Issue 4 (11th October 2022)

• Record Type: Journal Article
• Authors: Kaya, Batu; Geha, Paul; de Araujo, Ivan; Cioffi, Iacopo; Moayedi, Massieh
• Is Part Of: Human brain mapping. Volume 44:Issue 4(2023)
• Page Start: 1309
• Page End: 1319
• Publication Date: 2022-10-11
• Subjects: amygdala -- brain -- bruxism -- diffusion tractography -- masticatory muscles -- ultra‐high field imaging -- white matter; Brain mapping -- Periodicals; 611.81
• DOI: 10.1002/hbm.26104
• Languages: English
• ISSNs: 1065-9471

Abstract

Abstract: The neuroanatomical circuitry of jaw muscles has been mostly explored in non‐human animals. A recent rodent study revealed a novel circuit from the central amygdala (CeA) to the trigeminal motor nucleus (5M), which controls biting attacks. This circuit has yet to be delineated in humans. Ultra‐high diffusion‐weighted imaging data from the Human Connectome Project (HCP) allow in vivo delineation of circuits identified in other species—for example, the CeA–5M pathway—in humans. We hypothesized that the CeA–5M circuit could be resolved in humans at both 7 and 3 T. We performed probabilistic tractography between the CeA and 5M in 30 healthy young adults from the HCP database. As a negative control, we performed tractography between the basolateral amygdala (BLAT) and 5M, as CeA is the only amygdalar nucleus with extensive projections to the brainstem. Connectivity strength was operationalized as the number of streamlines between each region of interest. Connectivity strength between CeA–5M and BLAT–5M within each hemisphere was compared, and CeA–5M circuit had significantly stronger connectivity than the BLAT–5M circuit, bilaterally at both 7 T (all p < .001) and 3 T (all p < .001). This study is the first to delineate the CeA–5M circuit in humans. Abstract : The neuroanatomical circuitry of jaw muscles has been mostly explored in nonhuman animals. A recent rodent study revealed a novel circuit from the central amygdala (CeA) to the trigeminal motor nucleus (5M), which controls biting attacks. Here, we use an open‐source ultra‐high field (7 T) MRI database, the Human Connectome Project, to delinate the CeA–5M circuit in vivo in humans for the first time. As a negative control, we also performed tractography between the basolateral amygdala and 5M, as CeA is the only amygdalar nucleus with extensive projections to the brainstem. We further replicate this study at 3 T, to show that this circuit can also be resolved at this more widely available MRI field strength.