Lecture 19: Somatosensation

Question 1

Types of afferents in somatosensation

Answer 1

• somatosensation (skin, touch)
• visceral afferents (guts)
• special senses (vision,hearing)
• chemical senses (olfaction)

Question 2

Divergence for sensory systems and 5 destinations of nociceptive information

Answer 2

1. sensory cortex via thalamus
2. autonomic centers in brainstem/diencephalon
3. reticular formation
4. cerebellum
5. local arc reflexes

Question 3

Conscious somatosensation pathway

Answer 3

primary afferent (with DRG), decussates, has to go through thalamus to reach cortex, thalamic relay nucleus, neurons become internal capsule and then end at primary somatosensory cortex

Question 4

Somatotopy

Answer 4

neurons are organized in coherent map of the body

Question 5

sensory coding (intensity)
Population code:

Answer 5

intensity perceived is proportional to number of receptors activated