1.7 Somatosensation

Question 1

Which part of the thalamus do mechanoreceptor and nocireceptors both synapse in?

Answer 1

Ventral Posterior

Question 2

Explain small receptor fields and give an example

Answer 2

Highly discriminative - fingertips

Question 3

Explain big receotor fields and give an example

Answer 3

Sparse - Low discrimination - back

Question 4

Give an example of convergant sensory pathway

Answer 4

Rods in retina - allows for modulation

Question 5

Explain lateral inhibition and its purpose

Answer 5

when the centre of a receptive field has an increased stimulus - it inhibits adjacent receptive fields - decreased stimulus - shapes the sensory input

Question 6

Which parts of the body have the biggest parts in the sensory cortex

Answer 6

Hands, lips and tongue

Question 7

Name each Bodmann area ; 3b, 3a, 3b&1, and 2

Answer 7

3a - proprioception
3b - primary sensory cortex
3b&1 - cutaneous
2 - size and shape

Question 8

Which of the above areas are similar to the receptive fields to 2nd order neurons

Answer 8

everything except for 1, This is important in extraction and stereognosis.

Question 9

Explain the columnar organization

Answer 9

The cortex is organised in columns, each one representing a different modality or part of the body, each one may work differently to the other.

Question 10

Where is the secondary somatosensory cortex found

and function

Answer 10

It is located on the superior aspect of the lateral aspect, it is bilateral and it has higher secondary functions, such as sensorimotor integration, integration from both body halves and attention, learning and memory.

Question 11

What is the function of the posterior parietal cortex?

Answer 11

Involved in integrating sensory information, mainly recognition of objects by touch.