Somato-sensory stimulation

Complementary and alternative medicine (CAM) therapies include acupuncture, massage, touch therapy, chiropractic, aromatherapy, music therapy, etc. The beneficial effects of these therapies are, at least in part, due to stimulation of senosry neurons in our body. It has been demonstrated that somatic afferents from the skin and muscle are involved in the control of various autonomic functions.

images-2The spinal–supraspinal pathways responsible for somatosensory stimulation mainly comprise the posterior spinal cord column pathway and the spinothalamic pathway. Most peripheral thick myelinated afferent fibers activated by the discriminative touch and sense of vibration enter the ipsilateral dorsal column-medial lemniscus tract (posterior column pathway) and emerge into the contalateral spinothalamic pathway.

In contrast, the thinly myelinated or unmyelinated afferent fibers activated by pain and temperature are carried up by the contalateral spinothalamic tract to supraspinal levels (spinothalamic pathway). These impulses are further relayed to the thalamus, and ultimately sent to the primary somatosensory cortex.

In addition, these impulses are also relayed to other brain areas, including the brain stem, periaqueductal gray (PAG) and hypothalamus, via collateral connections.