PT  - JOURNAL ARTICLE
AU  - Green, Duncan G.J.
AU  - Kim, Jinhee
AU  - Kish, Stephen J.
AU  - Tyndale, Rachel F.
AU  - Hill, Matthew N.
AU  - Strafella, Antonio P.
AU  - Tong, Junchao
AU  - McCluskey, Tina
AU  - Westwood, Duncan J.
AU  - Houle, Sylvain
AU  - Lobaugh, Nancy J.
AU  - Boileau, Isabelle
TI  - Fatty acid amide hydrolase binding is inversely correlated with amygdalar functional connectivity: a combined positron emission tomography and magnetic resonance imaging study in healthy individuals
AID  - 10.1503/jpn.200010
DP  - 2021 Mar 01
TA  - Journal of Psychiatry and Neuroscience
PG  - E238--E246
VI  - 46
IP  - 2
4099  - http://jpn.ca/content/46/2/E238.short
4100  - http://jpn.ca/content/46/2/E238.full
SO  - JPN2021 Mar 01; 46
AB  - Background Upregulation of the endocannabinoid enzyme fatty acid amide hydrolase (FAAH) has been linked to abnormal activity in frontoamygdalar circuits, a hallmark of posttraumatic stress disorder. We tested the hypothesis that FAAH levels in the amygdala were negatively correlated with functional connectivity between the amygdala and prefrontal cortex, subserving stress and affect control.Methods Thirty-one healthy participants completed positron emission tomography (PET) imaging with the FAAH probe [C-11]CURB, and resting-state functional MRI scans. Participants were genotyped for the FAAH polymorphism rs324420, and trait neuroticism was assessed. We calculated amygdala functional connectivity using pre-determined regions of interest (including the subgenual ventromedial prefrontal cortex [sgvmPFC] and the dorsal anterior cingulate cortex [dACC]) and a seed-to-voxel approach. We conducted correlation analyses on functional connectivity, with amygdala [C-11]CURB binding as a variable of interest.Results The strength of amygdala functional connectivity with the sgvmPFC and dACC was negatively correlated with [C-11]CURB binding in the amygdala (sgvmPFC: r = −0.38, q = 0.04; dACC: r = −0.44; q = 0.03). Findings were partly replicated using the seed-to-voxel approach, which showed a cluster in the ventromedial prefrontal cortex, including voxels in the dACC but not the sgvmPFC (cluster-level, family-wise error rate corrected p < 0.05).Limitations We did not replicate earlier findings of a relationship between an FAAH polymorphism (rs324420) and amygdala functional connectivity.Conclusion Our data provide preliminary evidence that lower levels of FAAH in the amygdala relate to increased frontoamygdalar functional coupling. Our findings were consistent with the role of FAAH in regulating brain circuits that underlie fear and emotion processing in humans.