Pain is based on complex neurobiological processes. Often, pain is equated with nociception, but nociception is a part of the pain experience. Various nociceptive processes occur from the noxious stimulus to conscious perception. These include transduction, transmission, and modulation. Nociceptors, primarily Aδ and C fibers, respond to various noxious stimuli and transmit signals via the spinal cord to the brain. Transmission occurs via primary, secondary, and tertiary neurons, with important modulation processes taking place in the spinal cord. Facilitative and inhibitory mechanisms influence signal transmission, controlled by neurotransmitters such as glutamate and GABA. Pain perception in the brain is multidimensional and includes not only sensory nociceptive information but also affective and cognitive aspects.