Previously I had believed that synaptic pruning within the brain was something that happened only twice in your life: during the first years of life and during puberty. And that once this had happened your brain was moulded and set for life. However resent scientific advances, reported in the new scientist (20:08:11 edition) have suggested that this is not the case and in fact your brain is still remoulding its design, through synaptic pruning late into the twenties.
Moreover my belief that synaptic pruning was occuring in the first few years of life seems to have been wrong, as the article states that: “(dendritic) spine density increased rapidly during infancy reaching a peak before the 9th birthday”. Dendritic spines are small “door knob” shaped extensions of the dendrites, which have on their ends a PSD (post synaptic density). The role of the PSDs and therefore also the denritic spines is to recieve the incoming neurotransmitters, from an axon of another neuron and then send the message the signal to the neruon cell body (the soma).
By the age of nine then our brain has far too many connections between individual neurons. Over the next 20 years of our lives our brains are pruned so that half of these neurons are disconnected. this pruning is done to the crude: “Use it or loose it” principle. Therefore the neuron connectors we dont use – we loose. This neural pruning is believed to be crucial for learning and other cognative functions.
So whats the significance of this advancement? Well the disease schizophrenia is commonly developed whilst in the twenties. So now many neurologists and psychiatrists are theorizing that it may be due to a developmental complication, rather than a degenrative component. So we may be one step closer to curing a long incurable psychiatric disorder and who knows the further implications and applications this revelation could have – this is the beautiful ambiguity and mystery of science.