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Biol Psychiatry. 2010 Oct 15;68(8):748-54. doi: 10.1016/j.biopsych.2010.06.010. Epub 2010 Aug 16.

Inflammation-induced anhedonia: endotoxin reduces ventral striatum responses to reward.

Author information

1
Department of Psychology, Cousins Center for Psychoneuroimmunology, University of California, Los Angeles, California 90095-1563, USA. neisenbe@ucla.edu

Abstract

BACKGROUND:

Although inflammatory activity is known to play a role in depression, no work has examined whether experimentally induced systemic inflammation alters neural activity that is associated with anhedonia, a key diagnostic symptom of depression. To investigate this, we examined the effect of an experimental inflammatory challenge on the neural correlates of anhedonia-namely, reduced ventral striatum (VS) activity to reward cues. We also examined whether this altered neural activity related to inflammatory-induced increases in depressed mood.

METHODS:

Participants (n = 39) were randomly assigned to receive either placebo or low-dose endotoxin, which increases proinflammatory cytokine levels in a safe manner. Cytokine levels were repeatedly assessed through hourly blood draws; self-reported and observer-rated depressed mood were assessed regularly as well. Two hours after drug administration, neural activity was recorded as participants completed a task in which they anticipated monetary rewards.

RESULTS:

Results demonstrated that subjects exposed to endotoxin, compared with placebo, showed greater increases in self-reported and observer-rated depressed mood over time, as well as significant reductions in VS activity to monetary reward cues. Moreover, the relationship between exposure to inflammatory challenge and increases in observer-rated depressed mood was mediated by between-group differences in VS activity to anticipated reward.

CONCLUSIONS:

The data reported here show, for the first time, that inflammation alters reward-related neural responding in humans and that these reward-related neural responses mediate the effects of inflammation on depressed mood. As such, these findings have implications for understanding risk of depression in persons with underlying inflammation.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT00949845.

PMID:
20719303
PMCID:
PMC3025604
DOI:
10.1016/j.biopsych.2010.06.010
[Indexed for MEDLINE]
Free PMC Article

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