Central Nervous System (Part 2 - Sensory System Focused)

Question 1

what does the somatosensory system serve as ? (3 points)

Answer 1

1. the somatosensory system serves as the consultant between the different sensory modalities in the body
2. sends info from periphery to post central gyrus to convey info from environment
3. sensory neurones carry a unique modality of sensation to the somatosensory cortex

Question 2

state what it is meant by the key term - somatosensory processing

Answer 2

there is a tight link between sensory processing and movement production = somatosensory processing

Question 3

state what it is meant by the key term - somatosensory cortex

Answer 3

somatosensory information converges in the parietal lobe of the cerebral cortex, where it is processed to provide cohesive perception of your body and your physical environment

Question 4

state what it is meant by the key term - primary somatosensory cortex

Answer 4

located posterior to the central sulcus, on the post central gyrus of the parietal lobe

Question 5

why is S1 considered S1 ?

Answer 5

considered S1 as it receives direct somatosensory input from the thalamus, relayed from the periphery and the spinothalamic tract

Question 6

state what it is meant by the key term - homonucleus

Answer 6

representation of the body based on sensory information, not the size of the body part

Question 7

what is the function of S1 ?

Answer 7

S1 is associated with the identification of shape, size and texture

Question 8

what does S1 communicate with ? (2 points)

Answer 8

1. S1 communicates with S2, the posterior parietal cortex and the motor cortex
2. S1 relays info to M1, with ongoing sensory input used to refine and update descending motor commands

Question 9

state what it is meant by the key term - secondary somatosensory cortex

Answer 9

S2 is located in the lateral wall of the Sylvian sulcus

Question 10

what is the function of S2 ?

Answer 10

S2 is important for tactile object recognition, as well as tactile learning and memory

Question 11

what does S2 communicate with ?

Answer 11

S2 communicates with S1, motor cortex, Insular and the posterior parietal cortex

Question 12

what is the issue with damage to S2 ?

Answer 12

damage (lesions) to S2 result in deficits in learning through object manipulation

Question 13

state what it is meant by the key term - posterior parietal cortex

Answer 13

the PPC is a multi-sensory association area that integrates sensory information, including vision, somatosensory and auditory inputs

Question 14

state 2 additional facts about the PPC

Answer 14

1. PPC is involved in the control of, and error correction, in movements
2. also involved in movement planning to achieve a movement goal

Question 15

what percentage of people suffer with phantom limbs post amputation ?

Answer 15

approx. 65%

Question 16

state 2 additional facts about phantom limbs

Answer 16

1. representation of the missing limb in the brain leads to vivid experiences of the limb being there
2. often time, this representation in the brain may change or remain the same

Question 17

state what it is meant by the key term - stroke

Answer 17

a stroke is an event characterised by an alteration in blood flow (either blockage or bleed) in the CNS, resulting in a neurological deficit lasting more than 24 hours

Question 18

depending on the location of the stroke, what can the effects be ?

Answer 18

depending on the location of the stroke, both motor and sensory deficits can occur

Question 19

state 3 key symptoms of strokes

Answer 19

1. hemiparesis (weakness to one side of the body)
2. somatosensory loss - including proprioception and tactile information
3. somatosensory processing is altered and impacts rehabilitation - particularly balance and gait