Reticular Formation

Question 1

name the areas & their function

Answer 1

Question 2

What are the major functions of the reticular formation systems?

Answer 2

1. Pain - central group form ascending pathway for poorly localised pain, raphe neuron form descending inhibitory pathway, periaqueductal analgesia
2. Somatic motor - reticulospinal fibres
3. Visceral activity - maximal inspiration and expiration, cardiovascular and respiratory centres, viscera regulation via connection with hypothalamis/amygdala
4. Sleep and arousal - normal loss of consciousness (sleep) vs abnormal (injury or disease)

Question 3

Describe the concepts of wakefulness and sleep

Answer 3

consciousness is the state of awareness of oneself and surroundings, accompanied by neuronal activity in whole cerebral cortex.

Sleep is a normal loss of consciousness.

Question 4

Describe REM and non-REM Sleep

Answer 4

REM = rapid eye movement.
* muscles are relaxed (mediated by RF inhibition of spinal cord motor neurons)
* deeply asleep (significant stimulus needed for arousal - thalamus to cerebrum comms are inhibitied)
* cerebral cortex very active
* NA-ergic neurons no active, cholinergic neurons active (same as awake)

non-REM sleep
* lower levels of activity in systems that are active in REM sleep
* NA-ergic neurons decreased (but not off), cholinergic neurons off, gaba-ergic neurons on

Question 5

What system is active during wakefulness

Answer 5

locus coeruleus most active when awake, NA

Question 6

Which neurons in brainstem/hypothalamus promote sleep?

Answer 6

• serotonergic raphe neurons
• lateral hypothalamus
• suprachiasmatic nucleus of hypothalamus
• pedunculopontine and lateral dorsal tegnmental cholinergic neurons
• gaba-ergic neurons

Question 7

What role does the suprachiasmatic nucleus play?

Answer 7

24hr internal clock