Fudan Researchers Reveal Neural Link between Depression and Sleep Quality

Why the individuals with depression often suffer from sleep problems? People have been aware of the correlation between depression and poor sleep quality, but the reasons behind have long remained unknown. Recently, Professor Feng Jianfeng from Institute of Science and Technology for Brain-inspired Intelligence and his international cooperating team consisting of researchers from University of Warwick and Oxford University, for the first time, offer answers to these questions on the level of neural mechanism. Their findings show that the areas of brain such as the lateral orbitofrontal cortex, the precuneus, and the dorsolateral prefrontal cortex provide a neural basis for the association between depression and poor sleep quality. This study, for the first time, discovers a pathological mechanism of comorbidity between depression and poor sleep quality, and it might help to improve the sleep quality of the patients of depression, and even help to bring revolutionary advances to the treatment of depression. On July 25th (U.S. time), their research result entitled “Functional Connectivities in the Brain that Mediate the Association Between Depressive Problems and Sleep Quality” was published on JAMA Psychiatry, an internationally authoritative journal of mental illness.

Establishing a Scientific Chain of Evidence for the Correlation between Depression and Sleep Problems

The feedbacks of clinicians and depression patients indicate a strong correlation between depression and sleep problems. In order to understand the reasons, the team made use of the database of functional magnetic resonance imaging (fMRI). “To put it simply, we delved into large fMRI data, and found the neural circuit that mediates the association between depression and sleep quality.” As Dr. Cheng Wei introduced, the data set used for this investigation was selected from Human Connectome Project (HCP) and UK Biobank. And by preprocessing and analyzing the neuroimagings of over 10,000 subjects, the research team discovered that people with relatively poor sleep quality have a notable rise of the signal synchronization of functional connectivity among brain regions such as lateral orbitofrontal cortex (related with negative emotions), precuneus (related with reflections upon self and aspects of consciousness), dorsolateral prefrontal cortex (related with working memory), and so on. Meanwhile, the team also found out that people with high depressive problems scores also have similar rise of connectivity among such brain regions. It is the increased functional connectivity between these brain regions that mediates the correlation between depression and sleep quality. And Professor Feng Jianfeng explained that the increase connectivity between these brain areas may result in a long period of negativity, and therefore lead to a decline in sleep quality.

Mapping Clinical Treatment Targets for Two Major Modern Mental Health Problems

People of modern society are often troubled by the two major mental problems of depression and poor sleep. Circumstances as such further underlie the significance of this study to public health. Discovering the neural basic that is associated with both depression and sleep problems indicates a new target brain area that may help to treat these two psychological problems at clinical level. Specific stimulation of these brain regions may alleviate symptoms of both depression and poor sleep.

“As early as 2010, we already started on relevant researches,” said Professor Feng. And he further pointed out that his research team has long been working on issues concerning depression. Cooperating with many universities and hospitals, domestic or overseas, the team has one-third of its members of international background, and has gathered talents of various fields which include neurologists, neurobiologists, mathematicians, and psychologists. And this outstanding team has reaped a series of important achievements in their years of research on depression. For example, the paper published in Brain magazine in 2016, which accurately locates the abnormalities in certain functional brain regions related with depression, has been successfully applied in clinical research and achieved initial results. Another example is that the Medical School of the University of Toronto used 1 Hz transcranial magnetic stimulation to stimulate the lateral orbitofrontal cortex that is one of the abnormal brain areas that the team study showed. And after a month of treatment, it was clinically proven that this method can alleviate the clinical symptoms of pre-existing depression by 46%, and 33% for refractory depression.

Professor Feng said that at present, the team has basically integrated the existing genetic image databases of UK Biobank, HCP, ABCD, IMAGEN and so on. And it has also teamed up with several hospitals to collect comprehensive data on large-scale genetic imaging behaviors such as depression, schizophrenia, Alzheimer’s disease, autism, and common mental illnesses in stroke. With the simple hope of benefiting human health in mind, the team wishes to use a full-scale, multi-center biological metadata to develop a series of new intelligent algorithms in order to explore the reasons of major brain diseases and discover more possibilities for clinical treatment.
The first author of the research paper is Dr. Cheng Wei from the Institute of Science and Technology for Brain-inspired Intelligence Fudan University, and the corresponding author is Professor Feng Jianfeng. And the research was supported by National Natural Science Foundation of China and Shanghai Science and Technology Innovation Plan and so on.