Structural alterations of thalamic nuclei and their associations with leptin levels in patients with anorexia nervosa

Background

The thalamus is a complex subcortical brain structure that plays a role in various cognitive functions. Few studies have focused on thalamic nuclei-specific alterations and potential neurohormonal involvement in eating disorders including anorexia nervosa (AN).

Methods

We employed a FreeSurfer segmentation tool to compare thalamic nuclei volumes cross-sectionally between females with AN (n = 131, 12–29 years) and age-matched healthy females (HC, n = 131). Potential associations with BMI, leptin, and psychiatric symptoms were analyzed via robust linear regression.

Results

Most thalamic nuclei volumes were reduced in both hemispheres in AN versus HC. The spread of alterations ranged between −39.7 % and +3.8 % (average −9.8 %, η_p² = 0.16). Left laterodorsal and pulvinar inferior nuclei showed positive associations with leptin in AN. Leptin mediated the effect of BMI on both thalamic nuclei volumes.

Conclusions

In AN, thalamic nuclei are altered to different degrees with laterodorsal nuclei emerging as substantially reduced. Leptin seems to be mechanistically involved in the reduction of some thalamic nuclei, further supporting the investigation of experimental leptin treatment for AN. Effect sizes observed for thalamic nuclei reductions in AN exceed other brain structures as well as other psychiatric disorders, which demonstrates the importance of the thalamus as a target structure in research on AN.