The role of ERK/MAPK signalling in emotional behaviour &ndash; studies on <em>Braf </em>knockout and gain-of-function mutant mice.

In recent years, the ERK/MAPK signalling pathway has been implicated into emotional behaviour and the development of mood disorders. To unravel the roles of ERK/MAPK signalling in emotional behaviour, Braf knockout mice were analyzed to interfere with the ERK/MAPK signalling pathway in forebrain neurons. The juvenile depletion of ERK/MAPK signalling results in a reduction in anxiety, a diminished complexity of the hippocampal network, and the disregulation of the expression of 150 genes. In contrast, mutants with a late depletion of BRAF during adulthood showed normal anxiety levels, but increased depression-like behaviour. Besides its effects on emotions, my studies also revealed a regulatory function of the ERK/MAPK signalling on circadian activity. Taken together, these results on the roles and mechanisms of ERK/MAPK signalling in anxiety and depression contribute to the understanding of the development of mood disorders and may further enable the design of new therapeutic drugs