Brain development takes place significantly in the first part of life, and before birth. As a large and energy-hungry organ, its development starts from a simple location at the end of the nerve cord in the early embryo, to a highly complex structure with multiple areas, as neurons are synthesised in a stem cell rich part of the brain before migrating to their respective final locations.
Neuron axons then start forging their way into tissue to their destination, sometimes very far from origin, by sensing their environment. Some of them can overgrow and later get “pruned”.
New neurons continue growing, mainly before the birth of the individual. Newborns have brains with significantly more neurons than adults. The first part of life, baby to toddler i.e. 0-3 years old, is a critical time for the development of human learning and language acquisition. Children deprived of stimulation and care (environmental stimulation) lag behind in terms of speech development and cognitive function. The outlook for redressing these challenges is time-sensitive, and can have better or worse outcomes depending on whether the intervention was made before or after the first 6 months of life.
Language acquisition develops rapidly during this time, with new words being added to a child’s vocabulary constantly, and reaching several hundred words by the time they are a toddler.
The processing of new information is carried out by the brain in terms of synapse formation and retraction, which means that there is an excess of competition between the formation of new synapses, so unless the right environmental stimuli exists to create specific functions in the brain, it will fare less successfully in the future.
The timelines for peak synapse creation and pruning are the first few months of life for sensory pathways, followed a little bit later in the first year of life for language, and finally around the first year of life and beyond for higher cognitive function. All three overlap and peak in the first year of life.
Brain development continues to a lesser degree into the teenage years and adulthood, when individual synapses change, or even entire areas of the cortex are remapped. Factors contributing to these lasting changes over a lifetime, known as neuroplasticity, include the environment, thoughts and emotions.
Relevant outcomes of neuroplasticity are seen in learning, memory and recovery from brain damage. One man experienced loss of most of his brain but retained an outwardly unaffected appearance and function. If an area of the brain is injured, function can move to another area. Synapses can change as a result of whether, and how, they are used.
Focusing on specific patterns of learning or activity over a long period of time can boost the number and strength of synapses and dendrites in neurons, and eventually create a larger volume of the cortex that is associated to that activity.
Other outcomes of neuroplasticity have been observed in meditation with regards to changed activity in areas of the brain that process anxiety and cognition, as well as increased resilience against Alzheimer’s disease with greater levels education.