Researchers at Ben-Gurion University have devised simple computer-aided brain exercises that help individuals ignore negative stimulation. Functional MRI scans showed reduced activation in the brain region involved in negative emotions, including sadness and anxiety.

http://aabgu.org/brains-can-be-trained-to-regulate-negative-emotions/

http://www.sciencedirect.com/science/article/pii/S1053811915009866