• Low Folic Acid intake during pregnancy
• alpha fetoprotein are increased in amniotic fluid/maternal serum
• Other risk Factors: Trisomy 13 or 18
• Anticonvulsant drugs (Esp. VALPROIC ACID) during pregnancy

Pathophysiology of Neural Tube Defect: Failure of fusion of the lateral folds or rupture of previously  closed one

Failure of the posterior vertebral arches to close

Sacrolumbar region (L5-S1)

Tufts of Hair, dimple, or pit may overlie the defect

Meninges (arachnoid and subarachnoid space) protude through the defective spinal canal

• Meninges and Spinal Cord herniated through the spinal canal defect
• Paralysis
• Arnold Chiari Malformation Type 2

Anencephaly

Defective Close of the anterior neuropore and failure of the incorporation of the cerebrum into the systemic circulation.

Brain is absent and blood vessles are exposed to amniotic fluid

Very Common (freq. 1-5/1000 live births)

• orientation
• initiation/plan future
• motor cortex
• childhood/primitve reflex
• arithmatic/calculation
• personality

• Hippocampus (memory)
• Amygdala (seizure)
• Loss of fear/rage
• Loss of aggresion
• psychic blindess (not knowing how to respond) ex: hold door open but not walking through it
• Kluver-Buoy Syndrome
• Deja-Vu/Jamais Vu
• Hypersexuality ,Hyperorality
• Piriform/Periamyloid Cortx (olefactory)

• Hemineglect
• Spacial Neglect
• Anosognosia (not knowing you have a disease)
• Constructional Apraxia (can't copy a picture)
• Dressing Apraxia

-Cranial Nerve 6 is effected no abduction of the eye

-Cranial N. 3 is still intact Convergence is working

Incomplete separation of the cerebral hemisphere along the midline results in a single midline ventricular cavity enclosed within the forebrain

• Cyclopia (single eye in the mideline of the forehead is usually present)
• Associated w/ trisomy 13 and 18

Arnold Chiari Malformation

Enlargement of foramen magnum and subsequent herniation of the caudal aspect of the cerebellar vermis through it.  Cerebellar Vermis protrudes to the level of C3-C5; medulla also shifts downward

CSF obstruction  leads to Hydrocephalus

Frequent, asymptomatic and an incidental finding on autopsy. Downward displacement of the cerebellar tonsils

Arnold Chiari Malformation Type 2

Abnormally Small posterior Fossa results in downward displacement of the cerebellar vermis and medulla through the foramen magnum. Hydrocephalus

Respiratory Depression

Associated with Syringomyelia and meningomyelocele

Abnormally large posterio Fossa.

Cerebellar Vermis is absent and replaced by midline cyst that represents an expanded 4th ventricle. Brainstem nuclei are abnormal

Hydropcephalus is present

Ataxia,wide gait, (due to absence of CV) pushes Foramen M/L

• Blockage of Foramina Of Monroe
• Stenosis of the Aqueduct of Sylvius (e.g. Congenital Stenosis)
• Arnold Chiari Malformation
• Dandy Walker Malformation (cyst in cerebellum)
• Mdulloblastomas (tumor)
• Ependymomas(tumor)
• Pinealoma (Parinaud syndrome)
• Blockage of Foramina of Magendie and Luschka
• Choroid Plexus Papilloma (due to increase CSF production)

Post-meningitis adhesions

Meningiomas --> has somoma body

Choroid Plexus Papilloma (due to increase CSF production)

Papillary Carcinoma of Thyroid

Serous Cyst Adenoma of the Ovum

Mesothelioma

Meningioma

Neuroectoderm

1. Pineal
2. oligodendrocyte
3. neurophysio
4. astrocytes
5. retina
6. neuroepithelial cells

1. Sphinctet pupillae
2. Dialaror pupillae
3. Ciliary  muscle of the eye
4. Pseudounipolar ganglion cells

Upper Motor Neuron (spastic)

corticospinal tract(descending pathway)

• hyperreflex
• hyperspasm
• Clonus
• Rythmic contraction of the muscles in response to passive stretch
• Clasp Knife Rigidity
• Babinski + sign(normally disappears after 1 yr)
• Plantar Flexion (normal person has dorsal flexion)
• Contralateral effect in relations to lesion (above the medulla)

Lower Motor Neuron (Flaxid)

Corticospinal tract(descending pathway)

• Hypotonia
• Hyporeflexia
• loss of dorsal tone reflex
• Fasiculations
• flacid paralysis
• Areflexia
• No Babinski sign
• decrease muscle tone
• Ipsilateral effects (lesion @ lower medulla /spinal cord level)

Spinothalmic tract

(ascending pathway)

• pain
• temperature
• crude touch sensations from the extremities and trunk

Clinical Sign:

Patient comes in w/ presentation of analgesia (usually 1 or 2 segments BELOW the lesion) on one side of the trink/limb, location of lesion is CONTRALATERAL side of the brain stem or spinal cord.

CONTRALATERAL loss of pain and temperature in both below spinal cord and above medulla

EXCEPTION: is if the lesion is in the middle - bilateral loss of pain and temp.

Dorsal Column-Medial Lemniscus Pathway

(descending)

Sensory information for discrimination of:

1. touch
2. joint position ( kinestetic or conscious proprioception)
3. vibratory (pacinian corpuscle)
4. pressure sensation fr. trunk and limbs( meissner's corpuscle)
5. 2 point discrimination
6. below spinal cord ipsilateral to lesion
7. pass medulla contralateral to lesion

• is positive  when person sways when they  close their eyes.
• problem with Dorsal Roots of the Spinal nerves
• Vestibular System or Dorsal Root column lesions
• Dz. associated " Friedrich's Ataxia" (ataxia of gait)

• lesion of the ventral horns
• fecal oral route
• lower motor neuro symptoms /demylination
• Werdnig-Hoffman- Floppy Baby

1. Muscle weakness - partial or mild paralysis
2. Slurred speech and related speech problems
3. Paralysis - Total or near total loss of muscle strength
4. Jerking and twitching muscles, Tics
5. Partial numbness, tingling, buzzing and vibration sensations

• 60-70 yrs old person
• tx:tetracycline,erythrocycline,Floroquininone
•  { can be used when it 1st develops}

• corticopsinal tract and ventral horns
• Corticospinal tract for Voluntary Movement

Hemisection of the spinal cord

• Ipsilateral UMN signs (corticospinal tract) below lesion not shown
• Ipsilateral  loss of tactile vibration, proprioception (Dorsal Column) below lesion

• Bilateral  symptoms
• Gait abnormality
• masked by Corticospinal  tract paralysis

Vitamin B 12 Deficit

Pernicious anemia

(share same spinal cord pathology)

• subacute combined degeneration

Areas Affected:

1. Dorsal Column
2. Dorsal spinocerebullar tract
3. Corticospinal
4. Friedrich's Ataxia

Bilateral  loss of pain and temperature

Polio Characterics  - lower motor symptoms

ex: blisters in both hands  (dz. Arnold Chiari Malformation)

chromosome 22

ringing in 2 ears

"bilateral acoustic neuromas"

vascular lesions of the Medulla:

Vestibular Nuclei

1. Nystigmus
2. Vertigo

vascular lesion of the Medulla:

Inferior cerbellar Peduncle

1. dysmetria (decrease ability to measure)
2. dysiadschiosis
3. dystaxia
4. dysarthria

Vascular lesion of Medulla:

Lateral Spinothalmic tract

1. pain
2. temperature

Contralateral

vascular lesion of the Medulla:

Spinal Trigeminal tract and nucleus

1. V₁, V₂, V₃
2. Pain to the face (ipsilateral  pain/temp)

vascular lesion of the Medulla:

Cn. 9, 10

1. dysphagia swallowing liquids, foods, or saliva
2. dysarthria (loss of gag reflex)
3. slurr speech

vascular lesion of the Medulla:

Hypopthalamospinal tract of Horner

1. myadrosis (dialates the pupil)
2. Ptosis (drooping eyelids)
3. anhydrosis (lack of sweating)

Vertebral artery  occlusion

PiCA (posterior inferiorcerebellar arteryOcclusion )

CN. 9,10

Aka: Wallenverg's Syndrome

vascular lesion of the Medulla

Medial Medullary Syndrome

Anterior spinal artery Occlusion

CN. 12 (tongue deviates to the side of lesion)

Corticospinal syndrome

Dorsal Column Syndrome

Reticular activating system

responsible for  blood pressure

Respiration

CN. 9,10, 11, 12

consiousness

wakefullness

CN. 5,6, 7. 8

Disease associated with cranial nerve 6

• basal artery occl.--> pseudo-coma
• central pontine myelinosis --> "locked in syndrome>
• Leigh's Dz --> midbrain unaffected can't speak but they can use Cn. 3,4 to move their eyes

Vascular Lesion of Pons

• Medial Pontine Syndrome

Cn. 6 affected inability to adduct eye

artery lesion--> Paramedian Penetrating branchof the Basil artery

• symptoms are similar to medial medullary except for the Cranial nerve
• Tract affected: Corticospinal and DC
• CN. 7 --> Hyperacusis  (volume too loud )
• CN. 8 --> tinnitus, high pitch volume in the ear
• Lesion of MLF (Medial Longitudinal Fasciculus)

superior colliculus--> affects upward gaze

Consciousness, wakefulness (true coma)

Vascular lesion of the midbrain

Medial Midbrain Syndrome

• Crus cerebri
• WeberSyndrome (corticospinaltract,Corticobulbar tract affected)
• CN. 3

 

Lesion of the Midbrain

Posterior Midbrain

• Parinaud Syndrome (produce  by pineal tumor, compression of the superior colliculus
• hydrocephalus (increase pressure)
• papillary edema
• precautious puberty
• paralysis of upgrade
• papillary reflex abs.
• problem w/ insomnia (problem w/ sleep)

Anterior Inferior  Cerebellum Artery

• lateral striate artery
• lentriculostriate arteries
• Pure MOTOR ( corticobulbar, Corticospinal)
• Pure SENSORY (Spinothalmic, DCML)
• weakness paralysis of face,arms,legs, foot, toes
• sudden numbness
• trouble walking, dizzy,lost balance, coordination
• weakness of eye muscles, paralysis of eye muscles
• effects the internal capsule --> ant/post limb {genu}

Aneurysms

Anterior Communicating Artery

• Cn.3 is affected w/ corticobulbar and corticospinal fibers
• Corticobulbar tract they can still wrinkle their forehead/ move their upper face
• ptosis,mydriasis (dialated pupils)
• external strabismus
• accomodation + convergence area affected
• shut eyes + blink reflex intact
• contralateral spastic hemiparesis of both limbs
• contralateral lower face weakness (drop of corner of mouth)
• Cn. 5 is not intact (contralateral lower face wk)
• Cn.7 intact
• Nucleus ambiguous (Cn.9,10)

CN.3

• compression if this causes mydriasis
• mydriasis can also be caused by cocaine, amphetamine

serotonin secretion

Melatonin

• stroke
• diabetes
• hypertension
• Lateral Striate arteries or enticulostriatal arteries supply this area

• Pineal tumor compressing on the Sup. Colliculus
• paralysis of upward gaze
• dialated pupils (myadriasis)
• compression cerebral aqueduct (non.commun. hydrocephalus)

• Huntington Disease
• caudate shrinks in size (GABA/ AcH depletion)
• Hydrocephalus exvacus (large ventricle)
• alzheimers

Substantia Nigra

Hemiballismus (swinging of the arms)

• Located in the brain stem
• function - coordinate action of different parts of the CNS
• Regulation of muscle/ reflex activity
• control respiration, cardio respone, behavioral arousal + sleep

raphe nuclei- extends fr. medulla to midbrain

• 5-hydroxytryptamine from L-tryptophan
• plays a rold in mood aggression and the induction of non-rapid eye movement (REM)

locus caeruleus

synthesize NE and send projections to most brain areas involved in the contorl of cortical activation  (arousal ) decreases levels of NE are evident in REM, paradoxic sleep

• Hypothalmic tumors. infarct
• midbrain strokes
• lateral pontine
• lateral medullary
• Central Pontine Mylenosis
• Brown Segard Syndrome
• Syringomylial
• Anterior Spinal Artery Occlusion

Preganglionic Causes of Horner's

• Cervicothoracic cord trauma
• brachial plexus lesion
• neurofibromas
• cervical spondylosis
• pancoast tumor

Post-Ganglionic Causes of Horner's

1. Superior cervical ganglion tumor lesion
2. internal carotid artery dissection (trauma, tumor, thrombosis)
3. Lesion in the neck
4. skull based lesion
5. otitis media
6. cavernus sinus, thrombosis, inflammation, fistulas, aneurysm
7. cluster headaches

• Miosis
• anhydrosis
• ptosis
• damage to CN3 --> myadriosis
• damage to Diallator Papillae --> Miosis

Subfalcial Herniation

Cingulate Herniation

Subdural Hemmorage (CBT,CST)

causes mydriasis (CN3)

Tonsillar Herniation (Cerebellar Herniation)

Arnold Chiari Malformation

Downward Cerebellar Herniation downward

Respiration Collapse

Cavernous Sinus

• loss corneal reflex
• medial rectus palsy
• Horner's tract passes through here: Ptosis, Miosis, Anhydrosis
• Enlargement of the pituitary  laterally (lack of abduction)

• Normal Lab values
• Mild Headache
• since sella turica repture or membrane on x-ray  due to CSF
• Can't see pituitary Stalk

1. Lesion of Optic N. Chiasm (no reaction in either eye): Blind in the eye that has the lesion
2. Lesion of the retina ex:  optic neuritis,both eyes dialates

1. Lesion of the Pretectal Nucleus
2. No reaction to light, no reaction (prostitute/she accomdates)
3. Ciliary muscles work (accomodation intact)
4. Syphyllis
5. Older then 60

1.  complete lesion of 5  --> no blinking , no mastication
2. lesion of 7 on same side it won't respond

Visual Field Defects:

Optic Nerve

 blindness in that eye (anopsia)

Visual Field Defects:

Optic Chiasm (midsagittal lesion)

Bitemporal hemianopsia

disease cranial pharyngioma

Visual Field Defects:

Lateral Compression

Visual Field Defects:

Optic tract

Contralateral homonymous hemiansopsia

Visual field Defects:

Entire optic radiation

Visual Field defects:

Meyer's Loop (temporal lobe)

Visual Field Defects:

Upper Optic radiation (parietal lobe)

Visual field defects:

Visual Cortex

Visual field Defect:

Macula

can cause with or without macular sparing but if it is not a blood supply problem then macular not spared

Taste to posterior 1/3 of the tongue

Pain, Taste

• intention tremors
• dyschiadochokinesis (inability to perform rapid alterating movement)
• ipsilateral

Leg dystaxia (drunk bad gait)--> alcoholism

Ipsilateral

• truncal
• wide base gait
• legs far apart to stand to be stable due to cerebellum tumors
• Ipsilateral

• person will have problems with motor skills
• no fine tune movement uncoordinated tremors, all will be ipsilateral from the site of lesion

Tremor occurs when voluntary movements are performed

ex:

picking up a penny, slight tremors of the finger is evident and is increase when closer to the penny.Tremor is barely noticeable or absent @ rest.

pt. has a problem w/ finger to nose fast, inability to stop a movement @ a proper place.

Inability to recognize familiar objects, despite adequate sensation.

Inability to recognize objects placed in the hand.

area 3, 1, 2 --> astereoagnosis

inability to recognize familar faces.

temporal lobe

denial of a hemiplegic deficit (inability to recognize the presence of a hemiplegia)

Position agnosia; the inability to recognize the position of a limb  or digit in space.

the inability to write, a common symptom of aphasia

loss of the capacity for spoken and written language

also known as nonfluent, motor or expressive aphasia, it is characterized by difficulty in speaking, with preserved comprehension.

also called fluent, receptive or sensory aphasia, it is defined  by impaired comprehension, while speaking (fluency) is preserved.

preserved comprehension and fluent speech but with an inability to repeat words.

Loss of the inability to carry out certain movements correctly in response to stimuli that normally elicit them. It occurs through patient has no sensory loss, no weakness and no disturbance of language comprehension.

Loss of the ability to retrieve common nouns (such as names of animals, vegetables, tools and utensils).  It is due to a lesion of the inferior part of the temporal lobe, especially on the left.

UMN symptoms in the Leg (L)

Lateral aspects UMN symptoms in the (L) arm

Right Postcentral Gyrus/ Parietal

Loss of sensation in the (L) leg

lateral aspects

loss of sensation in the left arm

Music artistic language

1. NigroStriata--decreaseindopamine (parkinsons)
2. Mesolimbic/Meso-cortical  increase in dopamine (schitzophrenia)
3. Tuberoinfundibular (pituitary located) decrease in dopamine --> hormonal regulation, pregnancy, sensory process, maternal behavior
4. Area Postrema increase in dopamine,  Nausea + Vomiting

Olfactory

Smell (sensory)

Cn. 2

Optic

Sight (sensory)

Oculomotor

Eye movement, pupil constriction (motor)

accomodation, eyelid opening

Trochlear

Eye movement  (motor)

trigeminal

Mastication, Facial sensation (BOTH)

Abducens

Eyemovement (motor)

Facial Nerve

Facial movement, taste from anterior 2/3 of tongue, lacrimination,salivation(submaxillary and sublingual glands), eyelid closing

sensory and motor

Vestibulocochlear

hearing (sensory)

Glossopharyngeal

Taste from posterior 1/3 of tongue, swallowing, salivation (parotid glands), monitoring carotid body and sinus chemo- and baroreceptors

Vagus

Taste from epiglottic region, swallowing, palate elevation, talking, thoraco-abdominal viscera, (BOTH)

Accessory

Head turning, shoulder shrugging (MOTOR)

Hypoglossal

Tongue movement (MOTOR)

Cn. 1, 2, 3, 4

Cn. 9, 10, 11, 12