Scientists have discovered a subcortical neural pathway, responsible for the development of depressive behavior in mice after long exposure to night lighting. The path starts with the photosensitive ganglion cells of the retina and ends with neurons in the nucleus accumbens. Intermediate switching occurs in doralina periareolar the nucleus, the activation of which by night and leads to depressive behavior due to its direct connection with an adjacent nucleus, responsible, including, for mood. The authors of an article published in Nature Neuroscience, notes that the circadian rhythms of mice were not violated.
Depression (at least, exogenous) can trigger by many factors, ranging from excessive prolonged stress, ending with the disorders of physical health. In particular, the researchers as of symptom and factor in the development of isolated depression sleep problems: violation of sleep hygiene, which includes the lighting of the place of sleep, may be, for example, the reason for the failure of circadian rhythms and cause insomnia and provoke the development of depression. On the neural mechanism of such violations, however, little is known.
Scientists from the University of science and technology of China under the leadership of ena Kai (Kai An) investigated the effect of light on mice day and night. One group of mice every night at the same time for two hours shone with blue light, to another group, the control, illuminated only in the daytime. The experiment lasted three weeks and in mice, in which shone a blue light at night, began to observe depressive behavior: a decrease in physical activity and appetite. This behavior in mice persisted for three weeks after cessation of the experiment.