Neurotrophins are important brain proteins that support the health, survival and growth of brain cells. They act like fertilizers. Brain-derived neurotrophic factor (BDNF), insulin-like growth factor (IGF-I), nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) are some of the important ones. These neurotrophins are at very high levels in the brain during childhood development and help explain the speed and ease of new learning in children (think about language and music). It is important to know that after a brain injury these neurotrophins increase again; scientists call it ‘up-regulation’. Up-regulation means that the brain’s response to injury is to stimulate support cells to make more neurotrophins which in turn helps save struggling neurons and support the growth of new neurons and blood vessels to help repair the brain. Researchers have found that these neurotrophins appear for a discrete period of time which may explain the concept of the neuroplasticity window (read ‘The brain opens a neuroplasticity window’ post for some background). In future posts I will be discussing how sleep, exercise and diet affect neurotrophin levels and brain health.