Abstract
Anxiety impacts the quality of everyday life and may facilitate the development of affective disorders, possibly through concurrent alterations in neural circuitry. Findings from multimodal neuroimaging studies suggest that trait-anxious individuals may have a reduced capacity for efficient communication between the amygdala and the ventral prefrontal cortex (vPFC). A diffusion-weighted imaging protocol with 61 directions was used to identify lateral and medial amygdala-vPFC white matter pathways. The structural integrity of both pathways was inversely correlated with self-reported levels of trait anxiety. When this mask from our first dataset was then applied to an independent validation dataset, both pathways again showed a consistent inverse relationship with trait anxiety. Importantly, a moderating effect of sex was found, demonstrating that the observed brain-anxiety relationship was stronger in females. These data reveal a potential neuroanatomical mediator of previously documented functional alterations in amygdala-prefrontal connectivity that is associated with trait anxiety, which might prove informative for future studies of psychopathology.
Highlights
Altered function of the neural circuitry comprising the amygdala and the prefrontal cortex (PFC) has often been associated with anxiety (LeDoux, 2000; Davis and Whalen, 2001; Bishop, 2007; Hartley and Phelps, 2009; Casey et al, 2010; Milad and Quirk, 2012; Grupe and Nitschke, 2013), and this brain-anxiety relationship has been found in both humans and nonhuman primates (Birn et al, 2014)
In our previous work, using diffusion magnetic resonance imaging—an imaging method that measures water diffusivity in brain tissue using magnetic resonance images (MRI)—we demonstrated that the structural integrity of a white matter pathway between the amygdala and the ventral PFC was inversely correlated with self-reported levels of trait anxiety (Kim and Whalen, 2009; see Phan et al, 2009)
A separation between these two white matter tracts gradually became noticeable near the striatum: the amygdalavmPFC pathway comprised white matter passing through the ventral striatum into the PFC while the amygdala-lateral orbitofrontal cortex (lOFC) pathway included parts of the external capsule, and to a smaller extent, the anterior limb of the internal capsule that extended into the PFC
Summary
Altered function of the neural circuitry comprising the amygdala and the prefrontal cortex (PFC) has often been associated with anxiety (LeDoux, 2000; Davis and Whalen, 2001; Bishop, 2007; Hartley and Phelps, 2009; Casey et al, 2010; Milad and Quirk, 2012; Grupe and Nitschke, 2013), and this brain-anxiety relationship has been found in both humans and nonhuman primates (Birn et al, 2014). A number of dMRI-based analyses of amygdala-vPFC circuitry have detected a lateral white matter pathway that includes parts of the uncinate fasciculus—a major fiber tract that interconnects the anterior temporal lobe and the inferior frontal cortex (Ebeling and von Cramon, 1992)—but have identified a more medial white matter pathway (Johansen-Berg et al, 2008; Kim and Whalen, 2009; Clewett et al, 2014) The separation between these two white matter pathways becomes clearly distinguishable in the proximity of the striatum, as the lateral amygdala-vPFC pathway travels mostly in the external and the extreme capsules, coinciding with the uncinate fasciculus (Bucy and Kluver, 1955), whereas the medial amygdala-vPFC pathway passes through the ventral striatal areas (Fudge et al, 2002).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
