Poor maternal mental health in the perinatal period has been related to adverse outcomes for both the mother and the infant, and to parental conflict. The development of the child may be affected in several spheres, which include cognitive functioning, regulation of emotions, behavioural difficulties and psychological problems. The first three years of an infant's life are the most important and, during the early months, his mother in particular is the main source of highly arousing, visually affective communication. The importance of neurological stimulation for the infant is crucial, as recent studies have investigated the neurophysiology of the infant whose mother is depressed. There is reduced activity, particular in the frontal lobe, responsible for controlling behaviour and emotions. Changes have been found in the brain stem and mid-brain, responsible for alertness and sensation. Reduction of activity has also been found in the cortical and limbic functions, primarily responsible for emotional life and the formation of memories.