Adult Neurogenesis
Neurogenesis occurs in two main areas in the adult brain: the hippocampus and the olfactory bulb. The transformation of a new cell into a neuron appears to crucially involve a specific protein called WnT3, which's released by support cells called astrocytes. A chemical called BDNF also appears critical for the transformation into neurons. Most recently, T-cells have also been revealed as important for neurogenesis to occur. The extent and speed of neurogenesis can also be enhanced by various chemicals. Nerve growth factors appear to enhance the proliferation of precursor cells (cells with the potential to become neurons), and the prion protein that, damaged, causes mad cow disease, appears in its normal state to speed the rate of neurogenesis. The integration of the new neuron into existing networks appears to need a brain chemical called GABA. Indications are that moderate alcohol may enhance neurogenesis, but excess alcohol certainly has a negative effect. Most illegal drugs hav