somatosensory function Flashcards
discrimination: explain the principle of lateral inhibition and recognise the clinical importance of two-point discrimination to assess posterior column patency
what is two point discrimination
minimum distance at which 2 points are perceived as separate
what is two point discrimination related to
size of receptive field
somatosensory dermatomes significance
each spinal nerve has specific dermatome on skin, providing mapping system to localise level of sensory innervation perceived on body
somatosensory dermatomes: C5, C6, T4, T10
C5 clavical, C6 down thumb and index finger, T4 at nipples, T10 at umbilicus
what does lateral inhibition do
prevents overlap of receptive fields, allowing pinpoint accuracy of localisation of stimulus
what mediates lateral inhibition and how
inhibitory interneurones within dorsal horn of spinal cord (facilitates enhanced sensory perception (discrimination) due to inhibitory action on adjacent overlapping receptove fields)