For instance, I just read an article describing an area on the left hemisphere that is consistently smaller in dyslexics than normal readers and purports that dyslexia is a developmental syndrome of a failure of some cells to degenerate. This includes smooth and cardiac muscle and glands. Please ponder the fact that the only physical activities of the brain are to cause muscle contraction or glandular secretion. The ANS is divided into the sympathetic nervous system that is active when we are excited and the parasympathetic nervous system that is most active when we are at rest or digesting food. These are called fixed action patterns that are set off by key stimuli .
Examples are numerous feeding behaviors, sexual behaviors, etc.
The frog has one type of ganglion cell in its eye that only fires in response to a small dark object that moves against the background. The response it illicits is for the tongue to shoot out and catch flies. Properties of Neuronal Circuits Connections between nerve cells can get stronger and weaker. The specificity of a sensation depends upon where in the CNS the nerve connects. The output of a nerve cell is a function of all of its inputs.