An ascending somatosensory pathway can be considered literally as any axonal conduction route from the spinal cord or brain stem to higher levels of the brain. There are a number of such pathways, which convey somatosensory information to the brain for three purposes: arousal and attention, movement control, and the perception of somatic sensation. In this chapter, we will concentrate mainly, though not exclusively, on the ascending pathways that are generally believed to enable the organism to experience a conscious appreciation of energies impinging on transducers of the body surface and deep tissues. These sensory modalities are classified as tactile, nocisensory, and propriosensory and are typically described by terms such as touch, pressure, vibration, pain, heat, cold, position, itch, and tickle. The pathways extend from the peripheral transducers as far as the cerebral cortex and involve a minimum of three synaptic connections to get there (Fig. 12.1).