Meet the brain neurophysiology.
The central nervous system is composed of two main types of cells: the most numerous are glia, which have a supportive, protective and regulatory role, and neurons, which are the primary computing element. Neurons transmit information as a pulsed electrical code which is conducted down a specialized process (axon) that connects with other neurons. Each neuron can connect with many others, and each neuron can receive input from many others. At the sites of connection (synapses), information is transmitted across a small gap; small molecules (neurotransmitters) are released from the end of the axon, and these diffuse to receptor molecules on the receiving neuron. The latter then convert the chemical code back into an electrical signal that can be transmitted along the next axon. An important feature of synapses is that they are modifiable according to the prior history of activity in the system. This gives them an important role in learning, memory, and in adaptation to damage. Networks of neurons perform particular tasks. Those controlling movement are located in a number of adjacent areas of cerebral cortex. Some of these have axons that project to the spinal cord where they contact motoneurons that control particular sets of muscles; some have axons that interconnect the areas of the cortex; some have axons that project to subcortical groups of neurons in the basal ganglia and cerebellum. The presence of modifiable synapses in this complex network means that it is capable of learning new tasks and can react to injury by rearranging its connections to optimize function in undamaged parts.
Rothwell
John
J
Sobell Department, Institute of Neurology, Queen Square, London WC1N 3BG, UK.
D000818:Animals; D006801:Humans; D009044:Motor Cortex / Q000166:cytology* / Q000502:physiology*; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D013569:Synapses / Q000502:physiology