Reticular Formation and Consciousness Flashcards
Where does the brainstem end
The thalamus
True or False:
The reticular formation continues into the thalamus a tiny bit
True
True or False:
The reticular formation consists of a net like arrangement of neurons
True
What is the net like arrangement of neurons within (3)
- Central core of the brainstem (tegmentum)
- Top of the spinal cord
- Non-specific thalamic matter
True or False:
Cells of the reticular formation are located in the brainstem tegmentum
True
True or False:
The reticular formation lies outside major nuclei and tracts though it is connected to a variety of areas by an immense number of polysynaptic pathways
True
True or False:
The reticular formation receives input from nearly all sensory systems
True
What is the only sensory system that the reticular formation does not receive info from
Dorsal column - Medial lemniscus
True or False:
Has efferent connections, either direct or indirect with all levels of the CNS
True
True or False:
The reticular formation affects motor, sensory, and autonomic functions as well as the responsiveness of the cortex
True
What does a mesencephalic transection leave an unresponsive animal with (3)
- Abnormal pupils
- A continuously awake state (hypersomnia)
- Spontaneous breathing
What does a spinal cord transection leave an alert animal with (3)
- Sleep wake cycles (though altered)
- Normal pupillary reactions
- Normal EEG
Is the cat alert or unresponsive with a mesencephalic transection
Unresponsive
Is the cat alert or unresponsive with a spinal cord transection
Alert
True or False:
The reticular formation is not a diffusely organized set of cells
True
True or False:
The reticular formation has numerous specific nuclei that each have a precise and organized projection pattern
True
True or False:
The reticular formation is actually not net like
True
What are the specific NT released from nuclei in the tegmentum (5)
- Acetylcholine
- Dopamine
- Norepinephrine
- Serotonin
- Histamine
True or False:
Several CN nuclei are buried deep in the reticular formation
True
Where do the RF efferent projections travel long and short distances to (3)
- Forebrain
- Spinal cord
- Cerebellum
Where do the RF efferent long distance projections originate in
The medial 2/3 of the RF
Where do the RF efferent short distance projections originate in
The lateral 1/3 of the RF
How are the RF dendritic branches oriented
Perpendicular to the axis of the brainstem
What do the RF dendritic branches do
Maximize communication
RF efferent projections of the pons and medulla consist of (2)
- Long descending neurons that synapse with other neurons that contain a long ascending axon
- Bifurcating neurons giving rise to both the ascending and descending branches
True or False:
RF efferent projections have collateral connections
True
What do the collateral connections provide
Additional integrating mechanism
What is the simplified functional and organizational scheme of the RF
Consists of a central core of nuclei found in the brainstem tegmentum that run through the entire length of the brainstem
What is the RF continuous with rostrally
Certain diencephalic nuclei
What is the RF continuous with caudally
Within the intermediate zone of the spinal cord
What is the rostral continuation of the RF responsible for
Consciousness
What is the caudal continuation of the RF responsible for
Unconsciousness
What is the intermediate zone of the thoracic and sacral levels
Where the fibers of the RF come down and synapse on the gray matter
The rostral portion of the RF is in what structures (3)
- Mesencephalon
- Upper pons
- Some diencephalic nuclei
What is the function of the rostral portion of the RF
Necessary for maintenance of an alert, conscious state in the forebrain
What is another name of the rostral portion of the RF
Ascending reticular activating system (ARAS or RAS)
The caudal portion of the RF is in what structures (2)
- Pons
2. Medulla
What is the function of the caudal portion of the RF
Work together with the cranial nerve nuclei and the spinal cord to carry out a variety of motor, reflex, and autonomic functions
True or False:
The caudal reticular formation modulates motor output
True
True or False:
The ascending system of the RF is the same as the RF consciousness system
True
What does the reticular formation consciousness system consist of
Cortical and subcortical networks of the brain that carry out the major functions of consciousness
What is the reticular formation consciousness system formed principally by (2)
- Medial and lateral frontoparietal association cortices
2. Arousal circuits in the upper brainstem and diencephalon