Types
At any given moment, a neuron may be receiving postsynaptic potentials from thousands of other neurons. Whether or not threshold is reached, and an action potential generated, is dependent upon the spatial (from multiple neurons) and temporal summation (from a single neuron) of all inputs at that moment. In addition, the summation of excitatory and inhibitory influences will modulate the outcome. The closer a synapse is to the cell body of a neuron, the greater the influence on the final summation. This is due to the fact that the postsynaptic potentials travel through the unmyelinated dendrites to the axon hillock, where they are combined in summation. Because dendrites are unmyelinated the sustained membrane potential decreases increasingly over the amount of distance travelled.
Read more about this topic: Summation (neurophysiology)
Famous quotes containing the word types:
“The wider the range of possibilities we offer children, the more intense will be their motivations and the richer their experiences. We must widen the range of topics and goals, the types of situations we offer and their degree of structure, the kinds and combinations of resources and materials, and the possible interactions with things, peers, and adults.”
—Loris Malaguzzi (1920–1994)
“Our children evaluate themselves based on the opinions we have of them. When we use harsh words, biting comments, and a sarcastic tone of voice, we plant the seeds of self-doubt in their developing minds.... Children who receive a steady diet of these types of messages end up feeling powerless, inadequate, and unimportant. They start to believe that they are bad, and that they can never do enough.”
—Stephanie Martson (20th century)
“The rank and file have let their servants become their masters and dictators.... Provision should be made in all union constitutions for the recall of leaders. Big salaries should not be paid. Career hunters should be driven out, as well as leaders who use labor for political ends. These types are menaces to the advancement of labor.”
—Mother Jones (1830–1930)