Neuron Neuron A neuron, also known as a neurone (British spelling) and nerve cell, is an electrically excitable cell that receives, processes, and transmits information through electrical and chemical signals. These signals between neurons occur via specialized connections called synapses. Neurons can connect to each other to form neural pathways, and neural circuits. Neurons are the primary components of the central nervous system, which includes the brain and spinal cord, and of the peripheral nervous system, which comprises the autonomic nervous system and the somatic nervous system. There are many types of specialized neurons. Sensory neurons respond to one particular type
Intrinsically photosensitive retinal ganglion cells able to isomerize "all-trans-"retinal into "11-cis-"retinal when stimulated with light without help from additional cells. The two isoforms of melanopsin differ in their spectral sensitivity, for the "11-cis"-retinal isoform is more responsive to shorter wavelengths of light, while the "all-trans" isoform is more responsive to longer wavelengths of light. ipRGCs are both pre- and postsynaptic to dopaminergic amacrine cells (DA cells) via reciprocal synapses, with ipRGCs sending excitatory signals to the DA cells and the DA cells sending inhibitory signals to the ipRGCs. These inhibitory signals are mediated through GABA which is co-released from the DA cells along with dopamine.