VALO'S ARCHIVE

 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...

Abstract Heavy cannabis use has been frequently associated with increased rates of mental illness and cognitive impairment, particularly amongst adolescent users. However, the neurobiological processes that underlie these associations are still not well understood. In this review, we discuss the findings of studies examining the acute and chronic effects of cannabis use on the brain, with a particular focus on the impact of commencing use during adolescence. Accumulating evidence from both animal and human studies suggests that regular heavy use during this period is associated with more severe and persistent negative outcomes than use during adulthood, suggesting that the adolescent brain may be particularly vulnerable to the effects of cannabis exposure. As the endocannabinoid system plays an important role in brain development, it is plausible that prolonged use during adolescence results in a disruption in the normative neuromaturational processes that occur during this period....