H-shaped tray matter column (see figure below) at dorsal side of the spinal cord (i.e., situated toward the spine) and one of two major routes by which afferent information (i.e., somaesthesis) is carried to the thalamus via the dorsal roots (the other being the spinothalamic tract that transmits information about pain and temperature). Bilateral transection of the dorsal roots in monkeys leads to a loss of sensory feedback. While their movements appear to be more or less normal, they make more movement errors and have considerable difficulties learning new movements. Moreover, when the same procedure is carried out before normal movements have developed, the effects are even more strikingly obvious.
