Obviously, the amount and quality of light that a person encounters can significantly affect mood.

In a new study published in the Proceedings of the National Academy of Science, Brown University scientists used functional magnetic resonance imaging to determine how light intensity signals reach the brain and how brain structures involved in mood formation process those signals. The study showed that certain areas of the cerebral cortex involved in cognitive processing and mood are sensitive to light intensity.

The researchers used functional magnetic resonance imaging to study whole brain activation patterns in 20 healthy adults.

As part of the experiment, participants viewed four different levels of light intensity through glasses that diffused light and eliminated visual shapes, colors, and other objects in the environment. Participants looked at light of varying intensity, from dark to bright, for 30 seconds each.

Based on the results of the experiment, the researchers identified 26 areas of the human brain, in which activity either decreased or increased depending on the intensity of light. This activation occurred in the cerebral cortex, in various subcortical structures, and in the cerebellum, spanning areas with functions related to visual imagery, motor control, cognition, and emotion.

They found that light suppresses activity in the prefrontal cortex in proportion to light intensity. Light reactions in the prefrontal cortex and their change under the influence of light resembled the reactions of intrinsically photosensitive retinal ganglion cells.

In this study, scientists have shown that the prefrontal areas of the human brain have light-sensitive signals, and that these signals are similar to intrinsically light-sensitive retinal ganglion cells , according to scientists, can explain the effect of light intensity on complex emotional and cognitive behavior.