Neuron
From EvoWiki
A neuron is a type of cell specialized for the exchange of chemical signals between itself and other cells. Together with glial cells, neurons make up most of the nervous systems of animals. Many neurons are also specialized for the transmission of electrical signals along their surface membranes. Some neurons have axons, long thin extensions specialized to conduct electrical signals that move rapidly over long distances (up to several feet). There are three main classes of neurons:
- Sensory neurons. Some neurons are specialized sensory cells that detect light, vibration, heat or chemicals from the environment.
- Motor neurons. Some neurons connect to muscle cells and control muscle contraction.
- Interneurons. Some neurons connect sensory neurons to motor neurons. In humans, most neurons are interneurons. Interneurons are particularly important for learning and memory. Learning and memory result from changes in the synaptic connections between neurons.
Some specific types of large interneurons in the neocortex of humans have attracted the attention of neurobiologists who are trying to account for specialized features of human behavior. Human Betz cells have been suggested to be particularly important for fine motor control and human Meynert cells may be involved in visual adaptations such as recognition of predators in the type of open savanna environment where humans seem to have evolved.
A type of spindle-shaped neuron in the anterior cingulate cortex seems to be a special feature of certain primates including humans. Functional magnetic resonance studies have suggested that the anterior cingulate cortex is involved in several higher cognitive functions that involve the integration of information from multiple brain regions.
