11.5

Question 1

What does the primary somatosensory cortex (S1) do?

Answer 1

Receive projections from the thalamus; basis processing of somatosensory information (begins to construct perception)

Question 2

What does the secondary somatosensory cortex (S2) do?

Answer 2

Refines the construction of somatosensory perceptions; combines somatosensory information with visual and auditory information

Question 3

What are the four representations of the body in the somatosensory (S1) homunculus?

Answer 3

Muscles; skin (slow); skin (fast); joints, deep tissue pressure

Question 4

How does the somatosensory pathway participate in the dorsal visual stream?

Answer 4

Visual and somatosensory information is integrated to produce unconscious movements

Question 5

How does the somatosensory system participate in the ventral visual stream?

Answer 5

It provides haptic information about the identity of objects and status of completed movements

Question 6

What happens when S1 is damaged?

Answer 6

Impaired sensory thresholds, proprioception, hapsis, and simple movements

Question 7

What happens when S2 is damaged?

Answer 7

Does not disrupt plans for making movements, but does disrupt how the movements are performed; apraxia

Question 8

What is apraxia?

Answer 8

The inability to complete a plan of action accurately; inability to make voluntary movement

Question 9

The ______ somatosensory cortex (S1), arranged as a series of homunculi, feeds information to the _______ somatosensory cortex (S2), which also receives information from the ________ cortex and the ________ cortex

Answer 9

Primary; secondary; visual; auditory

Question 10

Damage to the secondary somatosensory cortex produces ________, an inability to complete a series of movements

Answer 10

Apraxia

Question 11

The somatosensory cortex provides information to the _______ stream to produce unconscious movements and also provides information to the _______ stream for conscious recognition of objects

Answer 11

dorsal visual; ventral visual

Question 12

Explain briefly why we can’t tickle ourselves

Answer 12

Studies show that unpredictability plays a role in the tickle perception, and because we can predict when we are about to tickle ourselves, we do not perceive the tickle sensation in these cases