Negative emotions and brain: Negative emotions mediates the association between structural and functional variations...

Emotion plays an important role in sleep quality, meanwhile, poor sleep quality is usually correlated with high negative emotions (NES). However, less is known about the neural basis for NES and the underlying mechanism for how NES affect individuals' sleep quality in the health brain. The present study combined voxel-based morphometry and resting-state functional connectivity analysis to identify the relationship between brain regions and NES, and then explored how NES-related brain structures are related to sleep quality in a large sample of normal young adults.

The present study used a fMRI procedure. Participants were 339 normal young adults. The NES was represented by the principal components of four measures: the Self-rating Anxiety Scale, Self-rating Depression Scale, Negative Affect Schedule, and Psychosomatic Tension Relaxation Inventory. Sleep quality was measured using the Pittsburgh Sleep Quality Index.

Results showed that higher NES scores were associated with larger regional gray matter volume (rGMV) in the left parahippocampal gyrus, right superior temporal gyrus, and right postcentral gyrus. Further functional connectivity analysis demonstrated that the connectivity between these three brain regions and a specific set of emotion-related regions was also significantly associated with NES scores. Moreover, NES acted as a mediator of the relationship between the rGMV of the left parahippocampal gyrus, right superior temporal gyrus, and right postcentral gyrus and sleep quality. NES also mediated the relationship between the connectivity between the right superior temporal-supplementary motor area and the right superior temporal-right precentral gyrus and sleep quality.

The present study provides the further evidence for neural substrates of NES and reveals a potential mechanism that NES mediates the effect of spontaneous brain activity on sleep quality. Meanwhile, these findings indicate that negative emotions share a common brain structure and function based on sleep quality.