Sensations from surgically transferred glabrous skin; central versus peripheral factors

Area of Science:

• Neuroscience
• Somatosensation
• Neuroplasticity

Background:

• Tactile acuity is crucial for hand function.
• Innervation density is theoretically linked to sensory perception.
• Previous models suggest a direct correlation between nerve fiber density and tactile sensitivity.

Purpose of the Study:

• To investigate the factors determining tactile acuity in reinnervated skin.
• To challenge the prevailing hypothesis that innervation density is the primary determinant of tactile acuity.
• To explore the role of central nervous system (CNS) organization in sensory recovery.

Main Methods:

• Skin grafts from the foot to the hand were reinnervated.
• Sensory thresholds were measured in the transferred skin.
• Comparison of sensory thresholds with theoretical predictions based on innervation density.

Main Results:

• Reinnervated skin in the hand exhibited sensory thresholds close to normal hand values.
• This recovery exceeded predictions based solely on innervation density.
• Observed sensory performance suggests factors beyond peripheral innervation.

Conclusions:

• Innervation density is not the sole or primary determinant of tactile acuity.
• The hand region of the central somesthetic map possesses inherent specialization.
• CNS specialization may provide a superior functional capacity for sensory processing in the hand, independent of peripheral nerve density.