#1 Reticular Formation

Question 1

______ is the Central core of the brainstem.

Answer 1

Reticular formation

Question 2

The Reticular formation is important in the regulation of what 6 things?

Answer 2

1. Posture
2. Some stereotypic motor behaviors
3. the internal environment
4. Pain regulation
5. Sleep & wakefulness
6. Emotional tone

Question 3

What are the 3 zones of the reticular formation? DESCRIBE EACH ONE.

Answer 3

1. Raphe or median = just adjacent to sagittal plane.
2. Paramedian or medial (Middle) = mixture of large and small neurons, source of most ascending and descending projections.
3. Lateral = prominent in rostral medulla and caudal pons, primarily involved in cranial nerve reflexes and visceral functions.

Question 4

What causes sleep paralysis?

Answer 4

When you wake up but your pons does not….

Question 5

RF divides into 3 tracts… what are they?

Answer 5

Two reticulospinal tracts:
- 1 Medial: pons; ipsilateral, descends near MLF & in anterior funiculus.

• 2 Lateral: medulla, descend bilaterally in lateral funiculus.

Question 6

The Reticular formation is the major alternative to the ________ in regulating spinal motor neurons.

Answer 6

Corticospinal tract

Question 7

Reticulo spinal tract neurons receive input from many areas including….

Answer 7

Cerebral cortex, basal ganglia, substantia nigra

Question 8

The vertical gaze center is found where?

Answer 8

Midbrain

Question 9

The horizontal gaze center is found where?

Answer 9

Pons

Question 10

Mastication pattern generator is located where?

Answer 10

Supratrigeminal Nucleus

Question 11

The Medulla “Vital center” controls what?

Answer 11

Locomotion
Heart Rate
Respiration
Swallowing & Vomiting

Question 12

Problems with the Reticular Formation can cause what stereotyped movement disorder?

Answer 12

Bruxism (tooth grinding)

*both opening and closing muscles are contracting at same time.

Question 13

What is the Central cause theory regarding Bruxism?

Answer 13

Sleep-related dysfunction cause bruxism. Input to supratrigeminal nucleus may be from basal ganglia, lateral hypothalamus and central nucleus of the Amygdala.

Question 14

How does the Reticular Formation moderate transmission in Pain pathways?

Answer 14

Periaqueductal gray (PAG) is central one well described pain suppression system.

Question 15

PAG receives pain info from ______ fibers.

Answer 15

Spinomesencephalic fibers

Question 16

PAG runs to _______ then to _______.

Answer 16

Raphe and then to posterior horn of spinal cord/spinal V nucleus.

Question 17

_______ work to control pain by activating PAG-raphe at multiple levels.

Answer 17

Opiates

Question 18

How is the Reticular formation related to Autonomic Reflex circuitry?

Answer 18

• A lot of visceral information reaches the RF.

- RF responds to environmental changes and PROJECTS to brainstem autonomics nuclei and spinal cord.

Question 19

RF Centers controlling inspiration, expiration and rhythm of breathing are located where?

Answer 19

In pons and medulla.

Question 20

Where are heart rate and blood pressure controls located?

Answer 20

Medulla

Question 21

True or false. The Reticular formation is critical in arousal and consciousness?

Answer 21

True!

• The RF projects to the thalamus and cortex!
• Midbrain and pons RF get input from multiple sensory modalities (pain &spinoreticular fibers)
• Project to thalamic intralaminar nuclei, ehich diffusely project to cortex.
• Heightens arousal in response to sensory stimuli or tasks that demand attention.

Question 22

RF _______ & ______ work together to modulate cortical activity.

Answer 22

Thalamic intralaminar nuclear projections & monoamine reticular projections

Question 23

What is the main monoamine of the brainstem?

Answer 23

Norepinephrine

*Also dopamine and serotonin

Question 24

What is the neurochemical signature of the hypothalamus?

Answer 24

Histamine containing neurons.

Question 25

What is the neurochemical signature of the Telencephalon?

Answer 25

Acetylcholine

Question 26

Where are Noradrenergic neurons found?

Answer 26

Medulla - solitary nucleus (memory enhancement) Rostral Pons - Locus Ceruleus - Cortex (arousal ) vigilance and attention. - Ventrolateral medulla - Spinal cord = pain regulation.

Question 27

Where is the Locus Ceruleus?

Answer 27

At base of Cerebellar Stalk ( looks like a black/blue sliver)

Question 28

True or false. Noradrenergic projection are very diffuse.

Answer 28

True! especially in somatosensory cortex

Question 29

What might a shortage of Norepinephrine cause?

Answer 29

Clinical depression - Locus Ceruleus activity is reduced. - Parkinsons disease patients often suffer from depression b/c locus ceruleus neurons are lost. * Drugs used to treat depression increase rate of firing at Locus ceruleus.

Question 30

What might increased levels of Norepinephrine cause?

Answer 30

Panic disorder

Question 31

What do the Neurons of the Locus Ceruleus do?

Answer 31

Respond to novel environmental stimuli. * Stimuli produces: - Increased state of arousal. - Feeling of anticipation * Norepinephrine released in cortex facilities attention to selected stimuli.

Question 32

Where is Norepinephrine realized to suppress incoming pain signals?

Answer 32

Spinal nucleus and spinal cord.

Question 33

Where are Dopaminergic neurons of the midbrain located?

Answer 33

- Substantia Nigra (putamen & caudate) | - Ventral tegmental area (limbic system)

Question 34

What are the divisions of the Ventral Tegmental Area responsible for? (2)

Answer 34

Mesocortical fibers = Organized thinking & planning; Heavy projections to frontal cortex. Mesolimbic fibers (Nucleus accumbens, amygdala) = emotional reward & drug dependency.

Question 35

Nigrostriatal neurons are important in what kind of function?

Answer 35

Motor function

Question 36

______ is major source of dopamine.

Answer 36

Ventral Tegmental area

Question 37

Schizophrenia is thought to be linked with problems of what area?

Answer 37

Ventral segmental area - Disorganized thinking (Frontal lobe) - Hallucinations (Limbic system/Temporal lobe)

Question 38

Schizophrenic hallucination are associated with ______ of dopamine in the limbic system.

Answer 38

High levels

Question 39

Schizophrenic social withdrawal is associated with _____ of dopamine levels in the prefrontal cortex.

Answer 39

Low levels

Question 40

Where are Serotonergic neurons located?

Answer 40

Pretty much all brainstem levels in raphe....so Raphe Nuceli.

Question 41

What is the ultimate function of Serotonergic neurons?

Answer 41

Help you focus and ignore distractions

Question 42

The midbrain raphe nuclei up to all regions of the cortex do what?

Answer 42

- attention = inhibition of distracting nuclei. | - Hypothalamus = day night cycle.

Question 43

The Medullary raphia nuclei down to spinal cord are know as what?

Answer 43

Nucleus Raphe Magnus

Question 44

Selective Serotonin Reuptake inhibitors are used for what?

Answer 44

Treatment of Clinical depression

Question 45

Serotonergic projections are very diffuse, but especially in what 2 areas?

Answer 45

Sensory and Limbic Areas

Question 46

What do low level of serotonin cause?

Answer 46

- High carb consumption - Binge eating - Carb preference in obese women

Question 47

What do high levels of serotonin cause?

Answer 47

- compulsive behavior and anorexia nervosa.

Question 48

Drugs that increase serotonin levels would be used to treat what?

Answer 48

Depression and Anxiety

Question 49

____ produces acetylcholine.

Answer 49

Cholinergic neurons found in the basal forebrain; basal nucleus (of meynert) & Part of RF = dorsolateral pontine tegmentum.

Question 50

What is one of the functions of the Dorsolateral pontine tegmentum of the RF?

Answer 50

Sleep and wakefulness

Question 51

Where do cholinergic projections project to?

Answer 51

to cortex mostly. | * a little bit to limbic also.