Sensation in living beings is enabled through various stimulus detection systems
which have evolved to facilitate the survival of the species. One such exquisite system
is the somatosensory system, which mediates exploration of the immediate
environment with respect to one's own body using the sense of touch. This system
contains dynamic representations of tactile inputs and interacts with other effector
systems to enable the organism to interact and adapt to the ever-changing environment.
The tactile inputs from the entire skin surface and the kinaesthetic inputs from the
joints are transmitted via sensory pathways through the spinal cord, brainstem, and
thalamus to the somatosensory cortex. Specifically, one of the pathways, referred to as
the dorsal column medial lemniscal (DCML) system enables fine tactile discrimination
and movements of our body joints. The primary somatosensory cortex has a
systematic representation of the body parts from head to foot in a lateral to medial
order. Similar maps of the body surface are also present subcortically in the thalamic
and brainstem somatosensory nuclei. Further, somatosensory neurons work in tandem
with the neurons in the motor cortex to produce the motor output.
