1. Medulla Oblongata
2. Pons
3. Midbrain

1. Serves as a conduit for the ascending and descending tracts between the spingal cord and the brain.
2. Contains important reflex centers, controlling the respiratory and the cardiovascular systems.
3. It contains nuclei of CNIII-CNXII

the substantia gelatinosa

they become continuous

consists of the lateral and anterior spinothalamic tracts and the spinotectal tract, which lie lateral to the decussation of the lemnisci

they convey sensory information to the thalamus

**Accessory nucleus (CN XI) and Hypoglossal nucleus (CN XII) are found here**

voluntary muscle movements

it receives afferents from the spinal cord, cerebellum and cerebral cortex

it sends fibers to the cerebellum

• olivary nuclear complex
• vestibular nuclear complex
• anterior post-cochlear nuclei
• nucleus ambiguus

What is found in the floor of the 4th ventricle?

(Medial to Lateral)

1. Hypoglossal nucleus
2. Dorsal nucleus of vagus nerve (CNX)
3. Nucleus of tractus solitarius
4. Medial and inferior vestibular nuclei

consists of ascending and descending tracts

connects the nuclei innervating the muscles of the eye and the vestibular nerve

coordinates eye movement

mediates nystagmus and lateral conjugate gaze

consists of a deeply placed continuous network of nerve cells and fivers that extends from the spinal cord, through the medulla, the pons, midbrain, sub-thalamus, thalamus, and hypothalamus.

it influences skeletal muscle activity, somatic and visceral sensations, the autonomic and endocrine systems and the level of consciousness.

Herniation of the tonsils of the cerebellum and the medulla through the foramen magnum.

Results in the blockage of the CSF passage at the roof of the 4th ventrical, causing internal (obstructive) Hydrocephalus which affects 1/1000 births.

Affected children may have: dysphonia, laryngeal stridor and respiratory arrest due to the involvement of CNX.

The lateral part of the medulla is supplied by the posterior inferior cerebellar artery, a branch of the vertebral artery. Thrombosis of either of these arteries causes:

• Dysarthria and dysphagia (ipsilateral pharyngeal and palatal muscle paralysis due to being innervated by the nucleus of ambiguus, CNX and CNXI)
• Analgesia and thermoanesthesia on the ipsilateral side of the face (damage to CNV).
• Vertigo, nausea, vomiting and nystagmus (damage to the vestibular nuclei, CN VIII)
• Horner's syndrome (damage to the ipsilateral descending sympathetic fibers)
• Gait and limb ataxias due to damage to the cerebellum and inferior cerebellar peduncle.
• Contralateral loss of sensation of pain and temperature (damage to spinothalamic tract)

The medial side of the medulla is supplied by the vertebral artery and its thrombosis leads to:

• Damage to pyramidal tract (contralateral hemiparesis)
• Damage to the medial Lemniscus (impaired contralateral sensation of position and movement and 2 point discrimination)
• Damage to the hypoglossal nerve (ipsilateral paralysis of the tongue muscles)

Between the medulla oblongata (below) and the midbrain (above).

Anterior to the cerebellum and is connected to the cerebellum by the Middle Cerebellar Peduncle.

1. Abducent (CNVI)
2. Facial (CNVII)
3. Vestibulocochlear (CNVIII)

Called Substantia Ferruginea

Due to a group of cells deep in there

1. Superior cerebellar peduncle
2. Median Sulcus
3. Medial Eminence
4. Sulcus Limitans
5. Area vestibuli
6. Facial colliculus

What are the two parts of the internal pons?

What causes the segmentation?

1. Posterior Part - Tegmentum
2. Anterior Part - Basal Part

Transversely running fibers called the Trapezoid body cause the segmentation.

1. transverse section through its caudal part passing through the facial colliculus
2. transverse section through its cranial part, the trigeminal nucleus

1. Nuclei of CNVII (vestibular nuclei) - regulates postural mechanisms and vestibulo-ocular reflexes
2. Motor nucleus of CNVII (facial nerve) - innervates all facial expression muscles
3. Nucleus of CNVI (motor to the lateral rectus muscle of the eye) - involved in lateral gaze
4. Motor nucleus of CNV (trigeminal nerve) - innervates the muscles of mastication

1. facial nucleus
2. abducent nucleus
3. medial vestibular nucleus
4. spinal nucleus of CNV
5. pontine nuclei
6. trapezoid nuclei

Motor

1. Corticospinal and corticonuclear tracts

2. Transverse pontine fibers

3. Medial longitudinal fasciculus

Sensory

1. Spinal tract of CNV

2. lateral, spinal, and medial Lemnisci

1. Main sensory nucleus of CNV
2. Main motor nucleus of CNV
3. Pontine nuclei
4. Trapezoid nuclei

Motor

1. Corticospinal and corticonuclear tracts

2. Transverse pontine fibers

3. medial longitudinal fasciculus

Sensory - Lateral, spinal, and medial lemnisci

1. ipsilateral facial muscle weakness (CNVII)
2. lateral rectus muscle weakness (nucleus of CNVI)
3. jaw muscle weakness (CNV)
4. weak hearing (cochlear nuclei) and Nystagmus (vestibular nuclei)
5. Contralateral hemiparesis or quadriparesis (corticospinal fibers)
6. Conjugate eye movement impairment (medial longitudinal fasciculus that connects nuclei of CNII, CNIV and CNVI)
7. no touch sensation in face and contralateral loss of touch in limbs and trunk (medial and spinal leminisci)

1. ipsilateral facial paralysis
2. contralateral paralysis of the limbs
3. paralysis of conjugate eye movement (CNVI and MLF)

1. cerebral peduncle (composed of crus cerebri)
2. tegmentum
3. substantia nigra (between the cerebral peduncle and the tegmentum)

1. coricospinal
2. coricobulbar
3. corticopontine

1. inferior colliculus
2. cerebral aqueduct of sylvius
3. trochlear nucleus
4. periaqueductal gray matter
5. substantia nigra
6. MLF, medial leminiscus, spinal leminiscus

binaural auditory inputs through the lateral leminiscus

it projects the medial geniculate body via the brachium of the inferior colliculus

connects the 3rd and 4th ventricles

**blockage causes hydrocephalus**

1. locus ceruleus
2. mesencephalic nucleus and tract
3. dorsal tegmental nucleus (endogenius pain control)
4. dorsal nucleus of raphe (5ht neurons)

pars compacta (dorsal)

pars reticulata (ventral)

receives GABAergic fibers from stratum

projects dopaminergic fivers to striatum

receives visual input form the retina, area 8 and area 19

receives auditory input to mediate audiovisual reflexes

involved in detection of movement in the visual field (searching, tracking, visual orientation)

parasympathetic fibers to constrictor pupil and cilliary muscles

involved in pupillary light reflex and accomodation

1. superior colliculus
2. brachium of superior colliculus
3. cerebral aqueduct of sylvius and PAG
4. Edinger-Westphal Nucleus
5. Red Nucleus
6. MLF, ML, SPL, Substantia Nigra

1. inferior colliculus
2. substantia nigra
3. trochlear nucleus
4. mesencephalic nuclei of CNV

Motor

1. Corticospinal and corticonuclear tracts

2. temporopontine

3. frontopontine

4. medial longitudinal fasciculus

Sensory

1. lateral, trigeminal, spinal, and medial leminisci

2. decussation of superior cerebellar peduncles

1. superior colliculus
2. substantia nigra
3. oculomotor nucleus
4. edinger-westphal nucleus
5. red nucleus
6. mesencephalic nucleus of CNV

Motor

1. corticospinal and corticonuclear tracts

2. temporopontine

3. frontopontine

4. medial longitudinal fasciculus

5. decussation of rubrospinal tract

Sensory - trigeminal, spinal, and medial leminisci

Occlusion of a branchy of the posterior cerebral artery that supplies the midbrain: (HAS PARALYSIS)

1. lesion to CNIII and crus cerebri - ipsilateral ophthalmoplegia
2. contralateral paralysis of the lower part of the face, tongue, arm, and leg
3. eyeball deviated laterally
4. ptosis of the upper lid
5. pupil is dilated and fixed to light and accommodation

Similar to Weber Syndrom, but necrosis is involves the medial leminiscus and the red nucleus (NO PARALYSIS)

1. contralateral hemianesthesia
2. contralateral involuntary movements of the limbs

1. Anterior
2. Middle
3. Flocculonodular 

1. Primary Fissure (between superior & middle lobes)
2. Uvulonodular Fissure
3. Horizontal Fissure 

Gray matter - cerebellar cortex

white matter - central

folia

each folium has a core of white matter covered superficially by grey matter

1. Molecular layer - external
2. Purkinje Cell layer - middle
3. Granular layer - internal 

what kind of cells does the molecular layer of the cerebellar cortex contain?

stellate cells and the inner basket cells

found along the folia's long axis

passes through the tranular layer and enters the white matter where it acquires a myelin sheath

terminate in cerebellar nuclei

4-5

have synaptic contacts with the mossy fibers

where do golgi cells send their dendrites?

their axons?

dendrites to molecular layer

axons synapsw with dendrites of granular cells

1. cortex of vermis
2. intermediate zones
3. lateral zone

what are the intermediate zones of th cerbellar cortex responsible for?

control the muscles of the distal parts of the limbs expecially the hands and the feet

immediately lateral to the vermis

vestibulospinal and reticulospinal tracts

concerned with balance

influences the rubrospinal tract

concerned with posture and muscle tone

influences from cerebral cortex via the thalamus and the rubrospinal tract

concerned with muscle coordination

1. dentate nucleus
2. emboliform nucleus
3. globose nucleus
4. fastigial nucleus 

1. intrinsic fibers - don't leave cerebellum; connect different folia and vermis on same side; some connect 2 hemispheres
2. afferent fibers - form greater part of white matter; proceed to cortex; lose myelin sheath and end as either climbing or mossy fibers. most pass through inferior and middle cerebellar peduncles
3. efferent fibers - output of the cerebellum; axons of the neurons of the cerebellar nuclei upon which the axon of the purkinje cells synapse. most pass through superior and middle cerebellar peduncles.

terminal fibers of the olivocerebellar tracts

enter molecular layer of cortex and branch to make multiple synapses with only one purkinje cell

few side branches synapse with adjacent stellate and basket cells

terminal fibers of all other cerebellar afferents

have multiple branches and exert more excitatory effect

single fiber can stimulate thousands of purkinje cells through granule cells

remaining cells in the cerebellar cortex, the golgi, basket and stelate cells limit the area excited by the purkinje cells by inhibiting these

1. inferior - arise form medulla
2. middle - arise from pons
3. superior - arise from lower midbrain 

pontine nuclei in the brainstem

produce the transverse fibers of the pons, and cross the midline to the opposite side to reach the cerebellar hemisphere

where does the Cerebro-olivocerebellar pathway originate?

terminate?

originates in the cerebral cortical neurons

terminates at the bilateral olivary nuclei

fibers from the inferior olivary nuclei cross the midline to the opposite side cerebellar hemisphere and terminate as climbing fibers

cerebellar afferent fibers that pass through the internal capsule and function in the control of voluntary movements.

cerebral cortex informs the cerebellum about initiation of th emovement, so that it can be monitored by the cerebellum

where does the cerebro-reticulocerebellar pathway originate?

terminate?

originates at the cerebral cortical neurons

terminates at boths sides of the reticular formation

the reticulocerebellar fibers enter the cerebellar hemisphere on of the side

originate in the innter ear (utricle, saccule, and semicircular canals)

terminate as mossy fibers to the cerebellum

what do the anterior and posterior spinocerebellar tracts convey information about?

how do they terminate?

muscle and joints

end as mossy fibers

Pontocerebellar Fibers

Origin?

Cells?

Cerebellar Peduncle?

Origin - Cortex

Cells - Pontine Nuclei

Middle Cerebellar Peduncle

Dorsal Spinocerebellar Tract (a Spinocerebellar Pathway)

Origin?

Cells?

Cerebellar Peduncle?

Origin - Leg Proprioceptors

Cells - Nucleus dorsalis of Clark

Inferior Cerebellar Peduncle

Cuneocerebellar Tract (a Spinocerebellar Pathway)

Origin?

Cells?

Cerebellar Peduncle?

Origin - Arm Proprioceptors

Cells - External Cuneate Nucleus

Inferior Cerebellar Peduncle

Ventral Spinocerebellar Tract (a Spinocerebellar Pathway)

Origin?

Cells?

Cerebellar Peduncle?

Origin - Leg Interneurons

Cells - Spinal Cord Neurons

Superior Cerebellar Peduncle

Rostral Spinocerebellar Tract (a Spinocerebellar Pathway)

Origin?

Cells?

Cerebellar Peduncle?

Origin - Arm Interneurons

Cells - Spinal Cord Neurons

Superior & Inferior Cerebellar Peduncles

Climbing Fibers

Origin?

Cells?

Cerebellar Peduncle?

Origin - Red Nucleus, Cortex, Brainstem, Spinal cord

Cells - Inferior Olivary Nucleus

Inferior Cerebellar Peduncle

Vestibular Inputs

Origin?

Cells?

Cerebellar Peduncle?

Origin - Vestibular System

Cells - Vestibular Ganglia & Vestibular Nuclei

Juxtarestiform Body

The major input source of the cerebellum is the _______1______ systems that originate in the __2__ cortex, primary ___3___ cortex, and __4___ cortex and relay through the ___5___ nuclei.

_______6_______ fibers then decussate and enter the cerebellum via the __7___ cerebellar peduncle.

1. Corticopontine
2. Motor
3. Sensory
4. Visual
5. Pontine
6. Pontocerebellar
7. Middle 

What is the Globose-Emboliform-Rubral Pathway?

What's its origin?

Where does it terminate?

Cerebeller Efferent Fibers that control ipsilateral motor activity

Originate - Clobose and Emboliform NN in Cerebellum

Terminate - contralateral red nucleus, then via rubrospinal tract to ipsilateral LMN.

What is the Dento-Thalamic Pathway?

Where does it originate?

Where does it terminate?

Cerebellar Efferent Fibers that control ipsilateral motor activity

Originate - Dentate Nucleus (cerebellum)

Terminate - contralateral thalamic nuclei, then to contralateral cerebral cortex

What is the Fastigial Vestibular Pathway?

Where does it originate?

Where does it terminate?

Cerebellar Efferent Fibers that control ipsilateral extensor tone

Originate - Fastigial Nucleus (Cerebellum)

Terminate - Vestibular nuclei, then via vestibulospinal tract to ipsilateral LMN.

What is the Fastigial Reticular Pathway?

Where does it originate?

Where does it terminate?

Cerebellar Efferent Fibers that control ipsilateral muscle tone

Originate - Fastigial Nucleus (Cerebellum)

Terminate - reticular formation, then via reticulospinal tract to ipsilateral LMN.

Lateral Hemispheres

Deep Nuclei?

Cerebellar Peduncle?

Output target?

Deep Nuclei - Dentate Nucleus

Superior Cerebellar Peduncle

Output Target - Ventrolateral Nucleus of Thalamus (VL), Parvocellular Red Nucleus

Intermediate Hemispheres

Deep Nuclei?

Cerebellar Peduncle?

Main Target?

Deep Nuclei - Interposed Nuclei

Superior Cerebellar Peduncle

Main Target - Ventrolateral Nucleus of the Thalamus (VL) and Magnocellular Red Nucleus

Vermis

Deep Nuclei?

Cerebellar Peduncle?

Main Target?

Deep Nuclei - Fastigial Nuclei

Uncinate Fasciculus (travels with Superior Peduncle)

Main Target - Ventrolateral Nucleus of Thalamus and Tectum

Inferior Vermis & Flocculonodular Lobe

Deep Nuclei?

Cerebellar Peduncle?

Main Target?

Deep Nuclei - Vestibular Nuclei & Fastigial Nuclei

Juxtarestiform body (travels with inferior cerebellar peduncle)

Main target - medial longitudinal fasiculus (eye movement pathways)

produce much less severe symptoms and signs than acute lesions do.

IE - slowly growing tumor

the muscles lose resilience to palpation. Shaking the limb produces excessive movemtns of the terminal joints

(loss of cerebellar influence on the simple stretch reflex)

Disturbances of voluntary movement

the muscles contract irregularly and weakly

Decomposition of movement - muscles fail to work harmoniously

Can't touch index finger to nose

inability to perform alternating movements regularly and rapidly.

Pronation/Supination of hand is slow, jerky and incomplete on the lesion side.

pendular knee jerk, tapping on the patellar tendon induces multiple flexion and extensions of the knee

(loss of influence of stretch reflex)

Nystagmus

(pendular type or jerk nystagmus)

Truncal - lesion of vermis causes wide-based, unsteady, staggering gait. Patient will often fall toward the side of the lesion and in severe cases they cannot even sit up without assistance

Appendicular - lesion of intermediate and lateral regions which affects finger to nose test

Brain metastases

alcoholism

multiple sclerosis

degenerative disorders of the cerebellum

Occurs when dorsal column - medial lemniscus pathway is damaged.

Impaired proprioception occurs.

Function improves with visual input and worsens with eyes closed or in the dark.

cerebellar astrocytoma

medulloblastoma

Friedreich's ataxia - idiopathic degeneration of dorsal columns and spinocerebellar tracts

posterior inferior cerebellar artery

anterior inferior cerebellar artery

superior cerebellar artery

PICA and SCA

Not AICA

1. Vertigo
2. Nausea
3. Vomiting
4. Horizontal Nystagmus
5. Limb Ataxia
6. Unsteady Gait
7. Headache 

Lateral Medullary Infarcts - Medullary symptoms also accur including Horner's Syndrome

Large Cerebellar Infarcts - cause cerebellar swelling leading to block of 4th ventricle apertures and hydrocedphalus

**Swelling in the posterior foss is life-threatening due to potential for brainstem compression!**

Central Core (Diencephalon)

Cerebral Hemispheres (Telencephalon)

Thalamus

Subthalamus

Epithalamus

Hypothalamus

optic chiasm

optic tract

infundibulum with the tuber cinereum

mammillary bodies

It's concealed by the fornix (originating from the hyppocampus of the temporal lobe and arches posteriorly over the thalamus to join the mammillary body).

Superior wall of the diencephalon is formed by the roof of the 3rd ventricle.

What is the lateral surface of the diencephalon bound by?

What does that consist of?

Bounded by the internal capsule of white matter

Consists of nerve fibers that connect the cerebral cortex with the brainstem and the spinal cord

Diencephalon is divided into two symmetrical halves by the 3rd ventricle, therefore its medial surface is also the lateral surface of the third ventricle.

The medial wall is formed by the thalamus (superior) and the hypothalamus (inferior)

Contains hypothalamic sulcus

Large, ovoid mass of gray matter that forms the major part of the diencephalin.

Important cell station that receives sensory tracts (NOT olfactory pathway) mainly from the contralateral side.

Information is integrated in thalamuse and relayed to the cerebral cortex and many other subcortical regions.

thrombosis

hemorrhage of a supplying artery

Lies inferior ot the thalamus

Between the thalamus and the tegmentum of the midbrain

crainial ends of the red nucleus and the substantia nigra

parts of the medial, spinal, and trigeminal leminisci

similar to a binconvex lens in shape

involved in the control of muscle activity through its connection to the corpus striatum

sudden, forceful involuntary movement in a contralateral extremity

the movement may be jerky (choreiform) or violent (ballistic)

habenular nuclei and their connections

pineal gland

received from the amygdaloid nucleus in the temporal lobe through the stria medullaris thalami

some of the fivers cross the midline to reach the havenular nucleus of the opposite side, these are havenular comissural fibers.

superior part of the stalk contains havenular commissure

inferior part of the stalk contains posterior commissure

two cell types (pinealocytes and glial cells)

sympathetic fibers and blood vessels

NO NERVE CELLS

extends from the optic chiasm to the caudal border of the mammillary bodies

lies below the hypothalamic sulcus

• Controls emotional states
• assists in regulation of fat, carbohydrate and water metabolism
• influences body temperature
• influences genital functions
• influences sleep
• influences food intake
• in close relation to the pituitary - controls the pituitary hormone releases

infection

trauma

vascular disorders

craniopharyngioma or chromophobe adenoma of the pituitary

pineal tumors

• genital hypoplasia
• genital atrophy
• diabetes insipidus
• obesity
• disturbances of sleep
• irregular pyrexia
• emaciation 

lateral ventrical

masses of gray matter (basal nuclei

nerve fibers

white matter (fibers embedded in neuroglia)

collection of masses of gray matter situated within each cerebral hemisphere

Corpus Striatum

Amygdaloid Nucleus

Claustrum

"internal capsule" lateral to the thalamus

divided into 2 nuclei by a band of nerve fibers - caudate nucleus and lentiform nucleus

1. Lentiform
2. White
3. Gray
4. Claustrum 

Receives afferent fibers from different areas of the cerebral cortex, the thalamus, the subthalamus, and the brainstem

Efferent fibers travel back to the same areas of the nervous system

Involved in muscular movement by controlling the cerebral cortex

situated in the temporal lobe close to the uncus

part of the limbic system

commissural fibers

association fibers

projection fibers

connect corresponding regions of the two hemispheres

these are:

corpus callosum

anterior commissure

posterior commisure

fornix

habenular commissure

largest commissure of the brain that connects the two cerebral hemispheres

lies at the bottom of the longitudinal fissure

rostrum

genu

body

splenium

transverse fibers that cross the midline

they connect the hippocampal formation of the two sides

connect various cortical regions within the same hemisphere

divided into short and long groups

Uncinate fasciculus - connects motor speech area with temporal lobe

Cingulum - in cingulate gyrus; connects the frontal and parietal lobes with parahippocampal gyrus.

afferent and efferent nerve fibers passing to and from the brainstem to the entire cerebral cortex

pass between large nuclear masses of gray matter within the cerebral hemisphere

ie: internal capsule

What would result from a lesion of the anterior 2/3 of the posterior limb of the internal capsule?

posterior 1/3?

progressive spastic hemiplegia

sensory impairments of the opposite side