Synaptogenesis

The synaptogenesis (Synapse σύν Greek syn ' together '; ἅπτειν haptein ' grab, grasp, grope '; genesis Greek γένεσις genesis, birth ',' origin ',' genesis ' ) refers to the creation or formation of new synapses on a neuron. The synaptogenesis, together with the elimination of synapses basis for the lifelong plasticity of the brain.

General

The majority of nerve cells or neurons prenatally developed through cell division and subsequent migration. The synaptogenesis dominated especially in the last trimester of pregnancy and in the postnatal period. At birth, the human being has accordingly already 100 billion neurons. This build using synaptic connections with each other, whereby initially caused much more synapses than are actually needed. Then there is an experience-dependent elimination of synapses. The synapse formation and elimination are achieved depending on the brain region, at different times their heyday. In the visual cortex, the peak of synapse formation is used for example in the first year of life. The frontal cortex, which is also responsible for the planning of action, forms only in the course of preschool age adequately synapses.

Elimination of synapses

Which synapses are eliminated and remain which is decided by the Hebbian learning rule. The more neurons fire together, the stronger the connection between the two. Accordingly synapses a strong connection persist, while synapses of a weak or missing links are eliminated. A distinction is made between experience-dependent plasticity and experience expected. Some synaptic connections must be strengthened by experience, not to be degraded. This includes for example the vision. If, in a so-called Kaspar Hauser attempt a living being reared in a completely dark room, wither the synapses of the visual cortex. The organism is then later even in a visually stimulating environment no longer able to perceive things visually. The synapse of the visual cortex is therefore dependent on experience. Experience-expectant synaptogenesis refers to the generation of synapses through an experience that makes the organism will not automatically be set before him by his environment ( such as sight, hearing and touch ), but. Example would be the formation of synapses in learning a foreign language.