Somatosensory system 2

Question 1

Dorsal column medial leminscal (DCML) pathway is responsible for what?

Answer 1

Discriminatory touch
Pressure
Vibration
Conscious proprioception

Question 2

Which pathway is responsible for discriminatory touch, pressure, vibration and conscious proprioception?

Answer 2

Dorsal column medial leminiscal pathway

Question 3

Crude touch
Itch
Tickle
Pain
Thermatosensation

Answer 3

Spinothalamic tract

Question 4

The gracile tract and the cuneate tract make up what?

Answer 4

The dorsal columns

Question 5

Sensory input above T6 travel in which tract? i.e. arms and upper trunk

Answer 5

Fasciculus cuneatus (cuneate tract)

Question 6

Sensory input to T6 and below travels in which tract? i.e. legs and lower trunk

Answer 6

Fasciculus gracilis (gracile tract)

this tract runs the length of the spinal cord

Question 7

V1

Answer 7

Opthalmic

Question 8

V2

Answer 8

Maxillary

Question 9

V3

Answer 9

Mandibular

Question 10

Brodmann area 3a responsible for what?

Answer 10

Body position

Question 11

Brodmann area 3b responsible for what?

Answer 11

Touch (texture, shape, stimulus size)

Question 12

Lesion in Brodmann area 3b would result in what?

Answer 12

Deficits in texture, shape, discrimination

Question 13

Brodmann area 1 responsible for what?

Answer 13

Texture discrimination

Question 14

Lesion in Brodmann area 1 would result in what?

Answer 14

Loss of texture dicrimination

Question 15

Brodmann area 2 responsible for what?

Answer 15

Object perception (size, shape of object - stereognosis)

Question 16

Lesion in brodmann area 2 would result in what?

Answer 16

Impaired grasping and size and shape discrimination (asterognosis)

Question 17

What is astereognosis?

Answer 17

The inability to identify an object by touch of the hands without other sensory input

Question 18

What is the SI?

Answer 18

Somatosensory cortex

Question 19

What is the SII?

Answer 19

Posterior parietal cortex

Question 20

How many layers in the somatosensory cortex?

Answer 20

6 layers

Question 21

Thalamic inputs to the somatosensory cortex terminate mainly on neurones in which layer?

Answer 21

Layer IV

Question 22

There are also columns in the somatosensory cortex - how are they arranged?

Answer 22

Each column consists of neurones with similar inputs and responses

Question 23

What do adjacent strips of the cortex map, map?

Answer 23

Adjacent strips of cortex, map the same parts of the body in parallel to each other

Question 24

The maps are not identical but ______ of each other?

Answer 24

The maps are not identical, but mirror images of each other

Question 25

What happens if e.g. a finger is lost in an accident/amputated, what happens to the area of the central sulcus that previously represented that finger?

Answer 25

It becomes utilised by other sensory inputs (e.g. will respond to stimulation of the adjacent digits and their cortical representation expands into the territory formerly representing that finger)

Question 26

Function of the posterior parietal cortex?

Answer 26

Receives and integrates information from the somatosensory cortex and other cortical areas: -visual, auditory and sub-cortical areas: -thalamus

Question 27

This part of the brain receives and integrates information from the somatosensory cortex and other cortical areas (visual, auditory) and other sub-cortical areas (thalamus)

Answer 27

Posterior parietal cortex

Question 28

Damage to the posterior parietal cortex causes what?

Answer 28

Causes bizarre neurological disorders! -e.g. agnosia, asterognosia, hemispatial neglect syndrome With simple sensory skills remaining intact