[Resting-state functional magnetic resonance imaging analysis of abnormal directional functional connectivity of the nucleus accumbens in patients with chronic tinnitus].

Abstract

Objective: To investigate abnormal directional functional connectivity of the nucleus accumbens (NAc) in chronic tinnitus patients using resting-state functional magnetic resonance imaging (fMRI), and to determine the relationship between the degree of this connectivity and tinnitus characteristics. Methods: The resting-state fMRI data of 40 patients with bilateral chronic tinnitus (12 males and 28 females, aged from 26 to 63(50.6±11.6) years) and 40 healthy controls with normal hearing (16 males and 24 females, aged from 26 to 70(45.9±12.4)years) were retrospectively enrolled from the Department of Otolaryngology, Nanjing First Hospital from January 2017 to January 2020. The bilateral NAc were selected as seeds to detect the directional functional connectivity with the whole brain, then the effective connectivity values between the two groups were compared using Granger Causality Analysis (GCA), and the correlation between the effective connectivity and the characteristics of tinnitus was calculated. Results: Compared with healthy controls, the effective connectivity from the left NAc to left middle frontal gyrus in patients with bilateral chronic tinnitus was increased [(1.0±0.2)vs(0.6±0.3)], the effective connectivity from the right NAc to left inferior frontal gyrus was enhanced [(0.9±0.3)vs(0.6±0.4)], the effective connectivity from the right middle temporal gyrus to left NAc was enhanced [(1.0±0.2)vs(0.5±0.3)], the effective connectivity from the right middle frontal gyrus to right NAc was also enhanced[(1.0±0.2)vs(0.5±0.3)](all P<0.05). After adjusting for age, gender, education level, and gray matter volume, positive correlations was observed between the Tinnitus Handicap Questionnaire (THQ) scores and increased effective connectivity values from the left NAc to the left middle frontal gyrus (r=0.386, P=0.020). Additionally, enhanced effective connectivity values from the right middle frontal gyrus to the right NAc was also positively associated with tinnitus duration (r=0.390, P=0.019). Conclusion: The directional functional connectivity between the NAc and prefrontal cortex in patients with chronic tinnitus is enhanced.