Reticular Formation Flashcards
name the areas & their function
What are the major functions of the reticular formation systems?
- Pain - central group form ascending pathway for poorly localised pain, raphe neuron form descending inhibitory pathway, periaqueductal analgesia
- Somatic motor - reticulospinal fibres
- Visceral activity - maximal inspiration and expiration, cardiovascular and respiratory centres, viscera regulation via connection with hypothalamis/amygdala
- Sleep and arousal - normal loss of consciousness (sleep) vs abnormal (injury or disease)
Describe the concepts of wakefulness and sleep
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.
Describe REM and non-REM Sleep
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
What system is active during wakefulness
locus coeruleus most active when awake, NA
Which neurons in brainstem/hypothalamus promote sleep?
- serotonergic raphe neurons
- lateral hypothalamus
- suprachiasmatic nucleus of hypothalamus
- pedunculopontine and lateral dorsal tegnmental cholinergic neurons
- gaba-ergic neurons
What role does the suprachiasmatic nucleus play?
24hr internal clock