Reticular Formation and Consciousness Flashcards
(105 cards)
1
Q
Where does the brainstem end
A
The thalamus
2
Q
True or False:
The reticular formation continues into the thalamus a tiny bit
A
True
3
Q
True or False:
The reticular formation consists of a net like arrangement of neurons
A
True
4
Q
What is the net like arrangement of neurons within (3)
A
- Central core of the brainstem (tegmentum)
- Top of the spinal cord
- Non-specific thalamic matter
5
Q
True or False:
Cells of the reticular formation are located in the brainstem tegmentum
A
True
6
Q
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
A
True
7
Q
True or False:
The reticular formation receives input from nearly all sensory systems
A
True
8
Q
What is the only sensory system that the reticular formation does not receive info from
A
Dorsal column - Medial lemniscus
9
Q
True or False:
Has efferent connections, either direct or indirect with all levels of the CNS
A
True
10
Q
True or False:
The reticular formation affects motor, sensory, and autonomic functions as well as the responsiveness of the cortex
A
True
11
Q
What does a mesencephalic transection leave an unresponsive animal with (3)
A
- Abnormal pupils
- A continuously awake state (hypersomnia)
- Spontaneous breathing
12
Q
What does a spinal cord transection leave an alert animal with (3)
A
- Sleep wake cycles (though altered)
- Normal pupillary reactions
- Normal EEG
13
Q
Is the cat alert or unresponsive with a mesencephalic transection
A
Unresponsive
14
Q
Is the cat alert or unresponsive with a spinal cord transection
A
Alert
15
Q
True or False:
The reticular formation is not a diffusely organized set of cells
A
True
16
Q
True or False:
The reticular formation has numerous specific nuclei that each have a precise and organized projection pattern
A
True
17
Q
True or False:
The reticular formation is actually not net like
A
True
18
Q
What are the specific NT released from nuclei in the tegmentum (5)
A
- Acetylcholine
- Dopamine
- Norepinephrine
- Serotonin
- Histamine
19
Q
True or False:
Several CN nuclei are buried deep in the reticular formation
A
True
20
Q
Where do the RF efferent projections travel long and short distances to (3)
A
- Forebrain
- Spinal cord
- Cerebellum
21
Q
Where do the RF efferent long distance projections originate in
A
The medial 2/3 of the RF
22
Q
Where do the RF efferent short distance projections originate in
A
The lateral 1/3 of the RF
23
Q
How are the RF dendritic branches oriented
A
Perpendicular to the axis of the brainstem
24
Q
What do the RF dendritic branches do
A
Maximize communication
25
RF efferent projections of the pons and medulla consist of (2)
1. Long descending neurons that synapse with other neurons that contain a long ascending axon
2. Bifurcating neurons giving rise to both the ascending and descending branches
26
True or False:
| RF efferent projections have collateral connections
True
27
What do the collateral connections provide
Additional integrating mechanism
28
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
29
What is the RF continuous with rostrally
Certain diencephalic nuclei
30
What is the RF continuous with caudally
Within the intermediate zone of the spinal cord
31
What is the rostral continuation of the RF responsible for
Consciousness
32
What is the caudal continuation of the RF responsible for
Unconsciousness
33
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
34
The rostral portion of the RF is in what structures (3)
1. Mesencephalon
2. Upper pons
3. Some diencephalic nuclei
35
What is the function of the rostral portion of the RF
Necessary for maintenance of an alert, conscious state in the forebrain
36
What is another name of the rostral portion of the RF
Ascending reticular activating system (ARAS or RAS)
37
The caudal portion of the RF is in what structures (2)
1. Pons
| 2. Medulla
38
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
39
True or False:
| The caudal reticular formation modulates motor output
True
40
True or False:
| The ascending system of the RF is the same as the RF consciousness system
True
41
What does the reticular formation consciousness system consist of
Cortical and subcortical networks of the brain that carry out the major functions of consciousness
42
What is the reticular formation consciousness system formed principally by (2)
1. Medial and lateral frontoparietal association cortices
| 2. Arousal circuits in the upper brainstem and diencephalon
43
What do the subcortical arousal systems result from
Result from diffuse projection systems
44
True or False:
| The diffuse projections of the subcortical arousal system each emanate from a single region to innervate many structures
True
45
Where do most of the subcortical arousal system projections in the brainstem that innervate the forebrain arise from
Upper brainstem
46
Where do the subcortical arousal system projections of the brain, cerebellum, or spinal cord arise from
Lower pons or medulla
47
True or False:
Some of the subcortical arousal system projections have their main source outside the brainstem in the hypothalamus or basal forebrain
True
48
The content of consciousness is comprised of systems mediating what (4)
1. Sensory
2. Motor
3. Memory
4. Emotional functions
49
What is the content of consciousness mediated by
Brain systems that provide the substrate (content) upon which the consciousness system acts
50
What does the content of consciousness depend on
What gets up to the thalamus
51
What is the level of consciousness regulated by
The consciousness system
52
What are the 3 processes involved in the level of consciousness
1. Alertness
2. Attention
3. Awareness
53
True or False:
| Consciousness is intentional integration of memory
True
54
Alertness depends on what
The RF
55
What circuits of the RF does alertness depend on (3)
1. Rostral brainstem
2. Diencephalic arousal circuits
3. Cortex
56
What circuits does attention use (4)
1. Rostral brainstem
2. Diencephalic arousal circuits
3. Cortex
4. Frontoparietal association cortices
57
True or False:
| Awareness is the least well understood of the levels of consciousness (alertness, attention, and awareness)
True
58
What does awareness refer to
Our subjective and personal experiences
59
What does awareness depend on
Our ability to combine various higher order forms of sensory, motor, emotional, and memory from wide regions of the brain into a unified summary of current mental activity which presumably can be remembered later
60
True or False:
| Working memory is part of awareness
True
61
True or False:
| Alertness is part of the ascending projection systems
True
62
What do lesions of the rostral brainstem and reticular formation and medial diencephalon cause
Coma
63
What can stimulation of the rostral brainstem and reticular formation and medial diencephalon lead to
Behavioral and electroencephalographic arousal fro deep anesthesia (brain thinks they are alert)
64
True or False:
| It is thought that anesthesia interferes with reticular formation Na+ channels
True
65
What regions make up the reticular activating system (RAS) (3)
1. Rostral brainstem
2. Medial diencephalon
3. Reticular formation
66
True or False:
It was found that the critical systems of the reticular activating system are not all ascending and do not all originate from the reticular formation
True
67
What does the RAS not all being ascending and not all originating from the RF cause
There to be multiple interconnected arousal systems acting in parallel to maintain consciousness
68
Lesions to what regions can cause coma (3)
1. Upper brainstem RF and related structures
2. Dysfunction of extensive bilateral regions of cerebral cortex
3. Bilateral lesions of the thalamus (particularly those involving the medial and intralaminar regions
69
What are the related structures of the upper brainstem RF that can cause coma (2)
1. Lower brainstem (pons and medulla)
| 2. Ventral midbrain or pons that spare the RF
70
Does a lesion to the lower brainstem (pons and medulla) effect consciousness
Nope
71
Does a lesion to the ventral midbrain or pons that spares the RF effect consciousness
Nope
72
What happens with lesion to the ventral midbrain or pons that spares the RF
Locked in syndrome
73
The upper brainstem neurons contain what NT (4)
1. Norepinephrine
2. Serotonin
3. Dopamine
4. Acetylcholine
74
Where do the neurons of the upper brainstem containing NE, serotonin, and dopamine project (2)
1. Cortical structures
| 2. Subcortical structures
75
Where do the neurons of the upper brainstem and pontomesencephalic RF neurons that contain acetlycholine project (3)
1. Thalamus
2. Hypothalamus
3. Basal forebrain
76
The posterior hypothalamic neurons contain what NTs (2)
1. Histamine
| 2. Orexin
77
Where do the posterior hypothalmic neurons project (2)
1. Cortical areas
| 2. Subcortical areas
78
What are histamine and orexin involved in
Sleep
79
The basal forebrain neurons contain what NTs (1)
1. Acetylcholine
80
Where do the basal forebrain neurons project (1)
1. Cerebral cortex
81
The neurons in the rostral thalamic intralaminar nuclei and other medial thalamic nuclei contain what NTs (1)
1. Dopamine
82
Where do the neurons in the rostral thalamic intralaminar nuclei and other medial thalamic nuclei project (1)
1. Cerebral cortex
83
Cholinergic projeciton systems release what
Acetylcholine
84
What are the functions of the cholinergic projection systems (3)
1. Arousal
2. Selective attention
3. Learning and memory
85
Cholinergic inputs to the thalamus cause what
Arousal
86
What do direct (mostly facilitory) inputs to cortex of the cholinergic projection system originate in
Forebrain
87
What are the functions of the noradrenergic projection systems (5)
1. Arousal
2. Selective attention
3. Sleep
4. Autonomic functions (with hypothalamus and amygdala)
5. Sensory processing (especially pain)
88
True or False:
| Pain will wake you up out of sleep but has no effect on coma
True
89
True or False:
| The ascending tract of the RF comes to life in dreams while the descending tract of the RF is paralyzed
True
90
True or False:
| Serotonergic projection systems have the most variations of its receptors
True
91
True or False:
| Serotonin is thought to have been around the longest
True
92
What are the functions of the serotonergic projection systems (5)
1. Arousal
2. Selective attention
3. Sleep
4. Sensory processing
5. Regulation of muscle tone and spinal reflexes
93
What is the function of the dopaminergic projection systems in the mesostriatal neurons (nigrostriatal neurons)
Regulates direct and indirect pathways for movement
94
What is the function of the dopaminergic projection systems in the mesolimbic neurons
Positive symptoms of schizophrenia
95
What is the function of the dopaminergic projection systems in the mesocortical neurons
Cognitive deficits and hypokinesia in parkinson's
96
What are the functions of the histamine projection systems (4)
1. Arousal
2. Sleep
3. Learning and memory
4. Energy balance
97
Where do the arousal circuits of the pontomesencephalic reticular formation travel through
The internal capsule
98
Does a person in the brain death stage of impaired consciousness have purposeful responses to stimuli, Behavioral arousal, sleep-wake cycles, brainstem reflexes, and spinal cord reflexes
Purposeful responses to stimuli: No
Behavioral arousal, sleep-wake cycles: No
Brainstem reflexes: No
Spinal cord reflexes: Yes
99
Does a person in the coma stage of impaired consciousness have purposeful responses to stimuli, Behavioral arousal, sleep-wake cycles, brainstem reflexes, and spinal cord reflexes
Purposeful responses to stimuli: No
Behavioral arousal, sleep-wake cycles: No
Brainstem reflexes: Yes
Spinal cord reflexes: Yes
100
Does a person in the vegetative stage of impaired consciousness have purposeful responses to stimuli, Behavioral arousal, sleep-wake cycles, brainstem reflexes, and spinal cord reflexes
Purposeful responses to stimuli: No
Behavioral arousal, sleep-wake cycles: Yes
Brainstem reflexes: Yes
Spinal cord reflexes: Yes
101
Does a person in the minimally conscious stage of impaired consciousness have purposeful responses to stimuli, Behavioral arousal, sleep-wake cycles, brainstem reflexes, and spinal cord reflexes
Purposeful responses to stimuli: Yes
Behavioral arousal, sleep-wake cycles: Yes
Brainstem reflexes: Yes
Spinal cord reflexes: Yes
102
What part of the brain is responsible for purposeful response to stimuli (1)
Cerebral cortex
103
What part of the brain is responsible for behavioral arousal, sleep-wake cycles (2)
Diencephalon and upper brainstem
104
What part of the brain is responsible for brainstem reflexes (2)
Brainstem reflex and motor systems
105
What part of the brain is responsible for Spinal reflexes (1)
Spinal cord circuits
