Decreased Connection Between Reward Systems and Paralimbic Cortex in Depressive Patients.

Tongjian Bai,Yang Chen,Kai Wang,Wen Xie,Qiang Wei,Yanghua Tian,Gong-Jun Ji,Meidan Zu,Chunlan Cai

doi:10.3389/fnins.2018.00462

Abstract

Despite decades of research on depression, the underlying pathophysiology of depression remains incompletely understood. Emerging evidence from task-based studies suggests that the abnormal reward-related processing contribute to the development of depression. It is unclear about the function pattern of reward-related circuit during resting state in depressive patients. In present study, seed-based functional connectivity was used to evaluate the functional pattern of reward-related circuit during resting state. Selected seeds were two key nodes in reward processing, medial orbitofrontal cortex (mOFC) and nucleus accumbens (NAcc). Fifty depressive patients and 57 healthy participants were included in present study. Clinical severity of participants was assessed with Hamilton depression scale and Hamilton anxiety scale. We found that compared with healthy participants, depressive patients showed decreased connectivity of right mOFC with left temporal pole (TP_L), right insula extending to superior temporal gyrus (INS_R/STG) and increased connectivity of right mOFC with left precuneus. Similarly, decreased connectivity of left mOFC with TP_L and increased connectivity with cuneus were found in depressive patients. There is also decreased connectivity of right NAcc with bilateral temporal pole, as well as decreased connectivity of left NAcc with INS_R/STG. In addition, the functional connectivity of right nucleus accumbens with right temporal pole (TP_R) was negatively correlated with clinical severity. Our results emphasize the role of communication deficits between reward systems and paralimbic cortex in the pathophysiology of depression.

Highlights

Depression is among common psychiatric disorders and the leading causes of disability worldwide (Ferrari et al, 2013)
AThe x, y, and z values are in Montreal Neurological Institute (MNI) coordinates. mOFC, medial orbitofrontal cortex; NAcc, nucleus accumbens; TP_L, left temporal pole; INS_R/STG, right insula extending to superior temporal gyrus; TP_R, right temporal pole
Our results should be interpreted with caution, and future investigations are needed divide participants into subgroups to clarify the distinct mechanisms underlying the specific subtypes of depressive individuals. It compared with healthy participants, the depressive individuals showed decreased connectivity of reward network with paralimbic cortex, including TP, insula

Summary

Introduction

Depression is among common psychiatric disorders and the leading causes of disability worldwide (Ferrari et al, 2013). As a heterogenous psychiatric disorder, diverse symptoms of depression may attribute to distinct pathophysiology (Drysdale et al, 2016; Guo et al, 2016). Anhedonia is regarded as a cardinal feature of depression (Pizzagalli, 2014) and associated with increased risk for suicide (Ducasse et al, 2018) and poor. Behavioral studies have revealed the abnormality during reward-related processing in depression (Rizvi et al, 2018), displayed several types such as reward response bias, impaired reward learning ability and increased risk avoidance (Smoski et al, 2009)

Methods

Discussion

Conclusion