Reticular Formation And Cerebellum

Question 1

What does the reticular formation consist of?

Answer 1

A substantial part of the dorsal part of the brain stem in which the groups of neurons and intersecting bundles of fibres present in netlike appearance in transverse sections.

Question 2

What functions does the reticular formation contribute to?

Answer 2

Sleep-arousal cycle
Perception of pain
Control of movement
Regulation of visceral activity

Question 3

How do parts of the reticular formation differ from one another?

Answer 3

Cytoarchitecture, connections and physiological functions

Question 4

What are an aggregation of neurons in the reticular formation called?

Answer 4

Nuclei

Question 5

What are the nuclei of the reticular formation?

Answer 5

Precerebellar nuclei
Raphe nuclei
Central group of nuclei
Cholinergic and catecholamine cell groups
Lateral parvocellular reticular area
Parabrachial area
Superficial medullary neurons.

Question 6

What paracerebellar reticular nuclei project to the cerebellum?

Answer 6

Lateral reticular nucleus
Paramedical reticular nucleus
Pontine reticulotegmental nucleus

Question 7

Where are the raphe nuclei located?

Answer 7

Groups of neurons either in or adjacent to the midline of the brain stem, interspersed among bundles of decussating axons.

Question 8

What do raphe neurons synthesise?

Answer 8

Serotonin

These serotonergic raphe neurons are thin, unmyelinated and greatly branched and are distributed to gray matter through the CNS.

Question 9

Which pathway in the raphe nuclei suppress the conscious awareness of pain.

Answer 9

Medullary raphe nuclei connects with the periaqueductal gray matter and the spinal dorsal horn

Question 10

Where does the pontine and mesencephalic raphe nuclei project to?

Answer 10

The cerebellum and all parts of the cerebrum, including the cerebral cortex, basal ganglia and lambic system

Question 11

Where are the central group of reticular nuclei located.

Answer 11

Medically located nuclei in the medulla and pons and the cuneiform and subcuneiform nuclei in the midbrain.

Question 12

What do central nuclei of the reticular formation receive?

Answer 12

Afferents from all the general and special sensory systems and from the reticular formation of the midbrain, the cholinergic reticular nuclei, the hypothalamus, and the pre motor area of the cerebral cortex.

Question 13

Where do ascending axons of the central romp of reticular nuclei travel in?

Answer 13

In the central tegmental tract

Question 14

What are the two groups of neurons that use acetylcholine as their synaptic transmitter in the reticular formation?

Answer 14

1. Pedunculopontine nucleus
2. Lateral dorsal tegmental nucleus

Question 15

What do the cholinergic neurons in the reticular formation receive?

Answer 15

Afferents from the nearby noradrenergic (locus coeruleus) and serotinergic (raphe) nuclei, from histominergic neurons in the hypothalamus and inhibitory GABA descending fibres from the pallidum and the pre optic area.

Question 16

Name the catecholamines

Answer 16

Dopamine
Noradrenaline
Adrenaline

Question 17

Where are the dopaminergic neurons located in the reticular formation?

Answer 17

Pars compacta of the substantia nigra and in the hypothalamus

Question 18

where is the largest group of central noradrenergic neurons?

Answer 18

Locus coeruleus or nucleus pigmentosus at the pontomesencephalic junction

Question 19

How do noradrenergic neurons function?

Answer 19

Fire spontaneously but are modulated by neurons in other parts of the reticular formation, the hypothalamus and the cortex of the orbital surface of the frontal lobe and the anterior part of the cingulate GYRUS.

Question 20

Where do efferent axons of noradrenergic neurons travel?

Answer 20

Efferent axons of the locus coeruleus travel rostrally in the central tegmental tract and the medial forebrain bundle.

Question 21

Where do descending noradrenergic axons arise?

Answer 21

Predominantly from the lateral medullary catecholamine nuclei.

Question 22

Where is the parvocellular reticular area located?

Answer 22

Medulla and pons, lateral to the central group and medial to the trigeminal nuclei.

Question 23

Where do neuron send their axons from the parvocellular reticular area?

Answer 23

To the motor nuclei of the Hypoglossal, facial, and trigeminal nerves.

Indicate involvement in feeding,

Question 24

Where are the parabrachial area located?

Answer 24

Lateral part of the reticular formation of the caudal midbrain, close to the superior cerebellar peduncle.

Question 25

Where do neurons from the parabrachial area project to and from.

Answer 25

Afferent fibres are from the solitary nucleus and from the cortex of the insula and adjoining parts of the parietal lobe.

Project rostrally to the hypothalamus, preoptic area, intralaminar thalamic nuclei and amygdala.

Question 26

The parabrachial area serves as a relay station for what?

Answer 26

In ascending pathways for visceral sensations.

Question 27

What region of the reticular formation is concerned with cardiovascular and respiratory regulation?

Answer 27

The ventral superficial reticular area in the medulla

Question 28

Describe the Afferents in the superficial medulla reticular neurons

Answer 28

Are from the spinal cord and solitary nucleus. They include fibres activated by the baroreceptors of the carotid and aortic sinuses and by the oxygen-sensitive chemoreceptors of the carotid and aortic bodies.

Question 29

Where do the efferent axons project to from the ventral superficial reticular area?

Answer 29

Project to the hypothalamus and to preganglionic autonomic neurons in the medulla and spinal cord

Question 30

At the level of the midbrain and ROSTRAL pons, the central tegmental tract consists of what three populations of axons from the reticular formation that directly or indirectly stimulates the whole cerebral cortex in regards to consciousness?

Answer 30

1. Noradrenergic neurons - more active when awake
2. Cholinergic neurons - active during the awake stage and in REM sleep.
3. Central group of reticular nuclei

Question 31

What is the function of the intralaminar thalamic nuclei?

Answer 31

Provides an essential link in most of the ascending pathways concerned with both arousal and REM sleep.

Question 32

How does the hypothalamus contribute to arousal?

Answer 32

Posterior part of the hypothalamus constains the tuberomammillary nucleus which is composed of histamine-secreting neurons. Histamine participates in arousal

Question 33

Which neurons in the brain stem and hypothalamus actively promote sleep?

Answer 33

1. Serotonergic raphe neurons - active in deep sleep
2. Orexins produced by neurons in the lateral hypothalamus - active in awake state
3. Suprachiasmatic nucleus of the hypothalamus - internal clock
4. Cholinergic neurons - active in REM sleep and in the awake state
5. Preoptic area - galanin. Active in deep sleep

Question 34

What is the role of the raphespinal tract?

Answer 34

Pathway best known for the involvement of its serotonergic neurons in the modulation of pain sensation.