Cannabinoid modulation of amygdala subregion functional connectivity to social signals of threat

• Published in: The international journal of neuropsychopharmacology Vol. 18; no. 3; p. pyu104
• Main Authors: Gorka, Stephanie M, Fitzgerald, Daniel A, de Wit, Harriet, Phan, K Luan
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01-02-2015
• Subjects: Adolescent; Adult; Amygdala - blood supply; Amygdala - drug effects; Brief Report; Double-Blind Method; Dronabinol - pharmacology; Facial Expression; Fear - psychology; Female; Functional Laterality; Healthy Volunteers; Humans; Image Processing, Computer-Assisted; Magnetic Resonance Imaging; Male; Nerve Net - blood supply; Nerve Net - drug effects; Neural Pathways - blood supply; Neural Pathways - drug effects; Oxygen - blood; Photic Stimulation; Psychotropic Drugs - pharmacology; Young Adult; cannabis; Δ9-tetrahydrocannabinol; functional connectivity; social threat
• ISSN: 1461-1457; 1469-5111
• DOI: 10.1093/ijnp/pyu104

Δ(9)-Tetrahydrocannabinol has been shown to modulate anxiety and facilitate the extinction of fear by inhibiting amygdala reactivity. Since functional coupling between the amygdala and prefrontal cortex is implicated in affective processes, it is possible that Δ(9)-tetrahydrocannabinol affects amygdala-prefrontal cortex functional connectivity in ways that differ across amygdala subregions: basolateral, centromedial, and superficial.
The aim of the study was to examine the effects of Δ(9)-tetrahydrocannabinol on functional connectivity between amygdala subregions and the prefrontal cortex during socio-emotional threat in healthy adults using a double-blind, placebo-controlled, within-subjects design. Sixteen subjects completed a functional magnetic resonance imaging task designed to probe amygdala responses to social threat. Amygdala subregion-prefrontal cortex functional connectivity was compared between Δ(9)-tetrahydrocannabinol and placebo using generalized psychophysiological interaction analyses.
Findings indicated that Δ(9)-tetrahydrocannabinol enhanced basolateral and superficial amygdala connectivity to the rostral anterior cingulate/medial prefrontal cortex.
These effects, including Δ(9)-tetrahydrocannabinol's potential ability to reduce threat perception or enhance socio-emotional regulation, may help understand the neurocircuitry of affect.