Synapses are structures that permit communication between neuronal cells.
One side of the synapse is presynaptic and the other postsynaptic. There are two types of synapses associated with hair cells. Action potentials are essentially pulses that travel down the fiber and carry information in a type of digital code. The brain cannot change the gain of chemoreceptor or photoreceptor sensory cells directly because, in contrast to hair cells, they are not innervated by nerve fibers from the central nervous system. All Rights Reserved.