Individuals can be protected from adverse mental health effects of poor sleep, especially those whose brains are more accustomed to rewards, reveal neuroscientists in a new study by Duke University.
‘Individuals who have higher reward-related Ventral striatum (VS) activity can cope with stress by responding positively.’
Poor sleep and Depression
The research team found that college students who had poor quality sleep and had higher activity in a reward-sensitive region of the brain were less likely to develop depressive symptoms.
These findings help the research team to understand as to why some individuals are more likely to experience depression, and some are not when they have sleep problems, revealed Ahmad Hariri, a professor of psychology and neuroscience at Duke University.
These findings may one day help us identify people for whom sleep hygiene could be more efficient or more relevant. The study appeared online in The Journal of Neuroscience.
The research team intensely studied ventral striatum (VS), a region deep within the brain, which helps in regulating the behavior in response to external feedback. The VS helps in reinforcing behaviors that are rewarded and reduces behavior that is not.
Electrical stimulation of the VS was found to reduce depressive symptoms in patients who are resistant to other forms of treatment.
In previous studies conducted by Hariri's team showed that individuals who had higher reward-related VS activity were found to be coping with stress.
Activity of the Ventral Striatum (VS)
Reut Avinun said, "We've shown that reward-related VS activity may act as a buffer against the adverse effects of stress on depressive symptoms."
Reut Avinun is the lead author of the study, who is a postdoctoral researcher in Hariri's group at Duke. He was keen in examining if the same moderating effect could be seen when looked at sleep disturbances.
Avinun investigated the brain activity of about 1,129 college students, who took part in the Duke Neurogenetics Study. Each participant in this study was given a series of questionnaires to evaluate their sleep quality and symptoms of depression. A fMRI scan was also done when the members were engaged in a task that activated the VS.
The participants were shown the back of the card, which is a computer-generated card and the task given to students was to guess the value of the card, whether it was greater than or less than five.
After guessing, the participants were given the feedback as to whether they were right or wrong. However, the game was rigged because during different trials the participants were either right or wrong 80 percent of the time.
Findings of the study
The research team compared the VS brain activity during trials to get information if general feedback or specifically reward-related feedback would buffer against depression, particularly when students were mostly right than those, who were mostly wrong and still were given feedback.
The research team found that those participants who were less susceptible to the effects of poor sleep had higher VS activity in response to positive feedback compared to negative feedback.
Hariri said that rather than being more or less responsive to the consequences of any actions, we could more confidently say that it is a reaction to positive feedback in doing something right, which is a part of the pattern. He also stated that this reward system gives the individual a deeper reserve.
"Poor sleep is not good, but you may have other experiences during your life that are positive and the more responsive you are to those positive experiences, the less vulnerable you may be to the depressive effects of poor sleep," explained Hariri.
- Reut Avinun, Adam Nevo, Annchen R. Knodt, et al. Reward-Related Ventral Striatum Activity Buffers Against the Experience of Depressive Symptoms Associated with Sleep Disturbances. Journal of Neuroscience (2017).DOI: 10.1523/JNEUROSCI.