Neural Circuits
Synapses
Input
All circuits have some sort of input, which is usually a set of axons which originate elsewhere and synapse within the local circuit. Inputs can also be from within. For example, while the thalamus brings sensory information into the cortex, by far the most numerous inputs to the cortex are from the cortex itself.
Output
Processing
Interneurons vary widely in structure and function, and can be both excitatory and inhibitory. The cerebellum contains as many as 1011excitatory granule cells, which are interneurons.
Networks
Local neural circuits usually operate in highly interactive, simultaneously interdependent, networks. While cells are arranged in series, within a circuit, there are usually massive numbers of circuits operating in parallel.
Circuits also communicate with each other, showing a tremendous amount of crosstalk.
Reflexes are among the simplest neural circuits.
Central pattern generators create rhythmic activity.
Modulatory systems have diffuse central connections and widespread effects.