Building your brain
Can we grow new nerve cells in our brains?
Some organs, such as the liver, can regenerate if they are damaged, and will grow to cope with demand (within limits). Exercise your muscles in the gym, and they get larger. Sadly, this will not work for your brain: although ‘exercising’ your brain may alter synaptic connections between neurons, the number of neurons will not change. Or will it? There is controversy about whether the brain can grow new neurons through a process known as neurogenesis, especially in the cerebral cortex, home of advanced thinking skills. If so, the numbers are small. The vast majority of neurons in the brain of the oldest man or woman have been there for their entire lifetime.
It was discovered in the 1990s that the hippocampus, where new memories form, can produce new neurons late in life. Since then, evidence has mounted that stem cells that make extra neurons are found in the cerebral cortex as well, at least in mice and monkeys. Recent evidence suggests that limited neurogenesis does occur within the adult brain but is restricted to two regions in the hippocampus and olfactory bulb. However, whether these new neurons contribute to overall brain function remains disputed.
Researchers are interested in how these new neurons are activated and whether this might suggest a mechanism for healing brain injuries after events such as a stroke, or even improving brain function.Lead image:
Biosciences Imaging Gp, Soton/Wellcome Images