Functions of Somatosensory Cortex

[E.S.Prakash]

From what I’ve read the somatosensory cortex has 2 components:

1.       Primary sensory area (SI)

2.       Secondary sensory area (SII)

It also notes that SI is used for ‘discrimination of different cutaneous and proprioceptive senses’ & SII for the ‘perception of sensation’. 

It notes that occurrence of a lesion of SI without involvement of the thalamus – discriminative senses are lost but sensations are still perceived. Does this mean SI is damaged but SII is OK?        

However it goes on later to say that lesions in SII produce ‘deficits in discrimination power whereas sensory processing in SI is not affected’

I thought discrimination power was a function of SI not SII.

Any clarification will be greatly appreciated.

Regards,

Waye Young

Year 2 Medical Student