PROPRIOCEPTION

roprioceptive information is transmitted up the spinal cord in the dorsal columns. A good deal of the proprioceptive input goes to the cerebellum, but some passes via the medial lemnisci and thalamic radiations to the cortex. Diseases of the dorsal columns produce ataxia because of the interruption of proprioceptive input to the cerebellum.

There is some evidence that proprioceptive information passes to consciousness in the anterolateral columns of the spinal cord. Conscious awareness of the positions of the various parts of the body in space depends in part upon impulses from sense organs in and around the joints. The organs involved are slowly adapting "spray" endings, structures that resemble Golgi tendon organs, and probably pacinian corpuscles in the synovia and ligaments. Impulses from these organs, touch receptors in the skin and other tissues, and muscle spindles are synthesized in the cortex into a conscious picture of the position of the body in space. Microelectrode studies indicate that many of the neurons in the sensory cortex respond to particular movements, not just to touch or static position. In this regard, the sensory cortex is organized like the visual cortex .