Every memory begins as a “spark” in the brain triggered when we receive input from our senses. This spark becomes an electrical signal as it travels from neuron to neuron. Each memory forges a unique pathway among the billions upon billions of neurons in the brain, as if blazing a new trail through a dense forest.
As the information passes from one neuron to the next, it jumps across gaps called synapses, with the help of neurotransmitters, such as serotonin and dopamine. Neurotransmitters are vital to memory-and, unfortunately, we produce less of them as we age.
But by continuing to challenge our brains to learn new skills and information, we can create more and more dendrites, which help keep our brains young and spry.
Work hard enough or long enough at a given type of memory and your brain will grow and adapt in other ways, too.
In a stunning 2000 study, London cab drivers, who spend their whole careers learning to navigate one of the largest, most-convoluted roadway systems in the world, underwent MRI screenings of their brains. The cabbies were found to have unusually large hippocampuses, an area of the brain that plays a major role in memory formation, particularly spatial memory.