The term "synaptogenesis" refers to the process that occurs when a new synapse is created within the central nervous system of an organism. The literal meaning of "synapse" is "to clasp." In less abstract terms, the synapse is where the end of one nerve cell, or neuron, meets another. Specifically, the synapse is where the end of the axon of one neuron meets the dendrite or cell body of the other.
The synapse is particularly important as it is where information is passed from one cell to another. The various components of a synapse include a synaptic knob of the presynaptic neuron, the synaptic cleft, and the postsynaptic knob. The information is passed across the synaptic cleft either through chemical or electrical means, although chemical neurotransmitters are the most common method of transmission.
There are two different places along an axon where synaptogenesis occurs. If the presynaptic ends form along the length of the axon, the formation of the synapse is said to be en passant. A new synapse that forms at the end of the axon, on the other hand, is called terminaux.
When a neuron is carrying a nerve impulse towards or away from the brain, it rarely passes the information to just one neuron. In most cases, each neuron has many synapses meeting the dendrites or cell bodies of other neurons. Each neuron can have several synapses with a following, and can also interact with several different neurons at the same time.
If an organism has a high degree of synaptogenesis, it will have an increased number of synapses forming. With more synapses, the central nervous system can pass messages at a quicker rate. As a result, the more synaptogenesis there is, the faster and more efficient the central nervous system.
The process of synaptogenesis usually occurs throughout the lifespan of an organism. This does not mean that synapses are forming at the same rate all the time. In most cases, there is a much higher level of synaptogenesis occurring when the brain is developing during early life. This process is of particular importance when pathways are initially forming within the brain.
When the brain is developing, there is competition between neurons to create strong pathways. Those that are used more often will develop into stronger pathways and have more neurons and synapses in them. Inhibiting, or not even using, a particular process during this developmental stage can lead to decreased numbers of synapses, and even the loss of neurons. This may result in problems later in life as the less-used processes may not go on to develop properly.