Dendrites integrate thousands of inputs locally before sending signals to central axon
A tiny neuron is a very complicated structure. Its complex network of dendrites, axons and synapses is constantly dealing with information, deciding whether or not to send a nerve impulse, to drive a certain action.
It turns out that neurons, at one level, operate like another complicated structure -- the United States, particularly its system of electing a president, through the Electoral College.
A new Northwestern University study provides evidence that supports the "two-layer integration model," one of several competing models attempting to explain how neurons integrate synaptic inputs. The findings are published in the journal Neuron.
In this model, each dendritic branch of a neuron receives and integrates thousands of electrical inputs, deciding on just one signal to send to the axon. The axon then receives signals from all the dendrites, much like electoral votes coming in from state elections, and a final decision is made. The result could be an output in the form of an impulse, or action potential, or no action at all.
"There are more than 100 billion neurons in the human brain, so detailed knowledge of individual neurons will lead to a better understanding of how the brain works, including the processes of learning and memory," said Nelson Spruston, who led the research team. He is professor of neurobiology and physiology in the Weinberg College of Arts and Sciences at Northwestern.