Reticular Formation Flashcards
What is the structure of the reticular formation?
Several zones of nuclei found in the central core of the brainstem that extends into the cerebrum as the hypothalamus
What are some major functions of the reticular formation?
Regulation of:
- posture
- some stereotypic motor behaviors
- internal environment
- pain regulation
- sleep and wakefulness
- emotional tone
What are the three longitudinal zones of the reticular formation?
- Raphe nuclei
- Medial zone
- Lateral zone
T/F: Reticular formation neurons have a simple connection pattern limited to the brainstem.
FALSE
RF neurons have complex connections, and my innervate multiple levels of the spinal cord, brainstem, and thalamus
What are the two reticulospinal tracts?
Medial: pons; ipsilateral and descends near the midline in anterior funiculus
Lateral: medulla; descends bilaterally in lateral funiculus
How does the reticular formation impact movement?
- It is an alternative to corticospinal tract; regulate spinal motor neurons
- Influence spinal motor neurons directly
- Regulate spinal reflexes
T/F: The main role of the reticular function is that in some cases it can bypass the brain for reflex like movements.
TRUE
What are some rhythmic motor patterns that are under control of the reticular formation?
- Gaze centers
- Mastication: supratrigeminal nucleus (pons)
- Locomotion
- Heart rate
- Respiration
- Swallowing
4-6 in the Medulla “Vital Center”
What is the central causes theory in relation to Bruxism?
Says that dysfunction in the reticular formation during sleep is leading to input to the supratrigeminal nucleus
What role does the reticular formation play in pain?
Can help to suppress pain when necessary
Briefly describe the PAG pain suppression pathway.
PAG receives pain info -> also receives input from hypothalamus, cortex, etc. -> the hypothalamus input can at times suppress the pain input
What types of medicines activate the PAG-raphe pathway to suppress pain?
Opiates
T/F: The RF can heighten arousal due to projections to the thalamus and cortex.
TRUE
What role does the ascending reticular activating system play?
Maintains consciousness and has a role in sleep-wakefulness cycle
In the reticular formation, what are the signature neurochemical makeups of the various nuclei?
Brainstem: norepinephrine, dopamine, serotonin
Hypothalamus: histamine containing neurons
Telencephalon: acetylcholine
What areas of the brainstem use norepinephrine?
Medulla: solitary nucleus, ventrolateral medulla
Rostral Pons: Lucas ceruleus
What are the two RF nuclei in the medulla and what are their functions?
Solitary nucleus: memory
Ventrolateral medulla: pain regulation
What is the RF nucleus in the rostral pons and what is its function?
Locus ceruleus: attentiveness
Where does the RF send noradrenergic (norepinephrine) projections?
Basically the entire CNS
What diseases are connected with abnormal levels of norepinephrine?
Decreased: Parkinson’s disease, depression
Increased: panic disorder
Where are RF dopamine transmitting neurons found?
Midbrain: substantia nigra, ventral tegmental area
What are the functions of the RF nuclei in the midbrain?
Substantia nigra: motor activity
Ventral tegmental area: organized thinking and planning, as well as emotional reward and drug dependency
Where does the midbrain send the most dopamine projections?
Frontal cortex
What disease is associated with the ventral tegmentum area?
Schizophrenia
What do changes in dopamine levels cause?
Decrease: social withdrawal
Increase: hallucinations
Where are seratonin transmitting RF nuclei in the brainstem?
All levels in the raphe
What RF nuclei transmit seratonin? What is their function?
Midbrain raphe nuclei: to all regions of cortex; inhibit distraction, keep track of day-night cycle
Medullary raphe nuclei: to spinal cord; pain suppression
T/F: Serotonin projections from the RF are very extensive and numerous.
TRUE
