Neuro Flashcards
Nuero Development
- Notochord causes overlying ectoderm to become neuroectoderm and neural crest cells come off.
- Notochord becomes nucleus pulposus
- Basal plate is motor and alar plate is sensory
Forebrain
- Telencephalon: Hemispheres and lateral ventricle
- Diencephalon: Thal and hypothal, third ventricle
Midbrain
-Mesenencephalon: midbrain, and cerebral aqueduct
Hindbrain
- Metencephalon: Cerebellum and pons (4th vent)
- Myelenchephalon: 4th ventricle
Neural Tube Defects
- Elevated AFP and AchE
- Occur before 8 weeks and are assocaited with decreased folic acid in the mother at the begning of pregnancy
- Valproic acid, carbemazapine, phenytoin (fetal hydantoin: Microcephaly, retardation, IUGR, cleft lips)
- Anti-epileptics are also common causes of cleft lip and palate, give phenobarbitol to pregnant women
SB
Meningomyelocele associated with chiari 2 (Paralysis below the lesion is common)
Anencephaly
- Failure of cranial neuropore to close
- Increased AFP and polyhydramnios
- Associated with DM1 and decreased folate
Holoprosenchephaly
- Failure of hemispheres to separate
- Associated with cleft lip and palate and maybe cycloplegia
- Patau is common cause
Chiari 2
Hernation of cerebellar tonsils and vermis
- Aqueductal stenosis and hydrocephalus
- Associated with syringomeyleia and meningomyelocele
Dandy Walker
Agenesis of the cerebellar vermis leading to dilation of the 4th ventricle and hydrocephalus
-Spina bifida can also commonly be seen
Syringomyelia
- Cystic dilation of central canal leading to compression of crossing spinothalamic results in loss of pain and temp in cape like distrbution
- May progress to involve symps (Lateral Horn) or motor
- May cause hydrocephalus and headaches
- Associated with chiari malformations
Tongue Development
- Anterior 2/3 is bordered posteriorly by the foramen cecum and terminal sulcus. Senstation from arch 1 in V3 and taste from arch 2 in VII. Sends axons to solitary nucleus
- Post 1/3 formed by 3rd and 4th arches. Glossopharyngeal is tongue tast and sensation, X is palate taste and sesnation, send axons to nucleus soliatarius
Arch 1
V2,3
-Mandilble, muscles of matication, inner ear muscles, general sensatino to face and tongue
Arch 2
Facial, PANS to facial glands, sensation around ear and motor to ear and face
- Facial artery, hyoid, musles of inner ear
- Taste to ant 2/3 sent to solitary
Arch 3
Sytolopharungeus, post tongue taste and sensation, solitary nucleus. Internal carotid artery from 3rd aortic arch
-Thymus, PTH, Hyoid
Arch 4
- Aortic becomes subclavian and arch
- Post tongue, vagus above runs with superior laryngeal
- cricothyroid
- taste and aortic arch to nucleus solitarius
- Superior PTH,
Thyroid
Invagination of endodermal floor
-Foramen Cecum and cyst possible
Muscles of tongue
Derived from occipital myotomes and are innervated by 12 from
Narcolepsy
- Genetic defect in orexin from the lateral hypothalamus
- Begins with REM sleep and causes cataplexy, associated with hallucinations leading to and coming out
Neronal Cell origin
Majortiy derived from neuroectoderm excpet Schwann and PNS from NC
-Microglia are mesodermal
Microglia
-When infected with HIV fuse to form multinucleated giant cells
Wallerian Degeneration
- PNS, retraction proximal, disllolution dystal. Nucleus moved to periphery and dissultion of Nissl substance.
- Recovery occurs.
- Loss of nuclear integrity leads to death
Oligodendrocytes
These cells are destroyed in MS
Schwann Cells
- Neural Crest
- Destroyed by Guillan Bare (Ascending paralysis)
- Acoustic Neuroma NF-2
Miessners Copuscles
Dyamic fine touch and position sense, glaborous skin (hairless)
Pacinian
Deep skin layers. Vibration and pressure
Merkels discs
Hair Follicles
-Pressure, static touch,
Peripheral Nerve
Endoneureum: Invests individual nerves, site of inflammation in GB
- Perineureum: Surrounds a fascile, site of reattacment in surgery
- Epineureum: Carries blood vessels
Merkels Discs
Slowly adapting, deep pressure
Meisners orpuscles
Smooth, glaborous hairless skin for fine touch
Pacinian Corpuscles
-Vibration and pressure
NE
- Pons in locus ceruleus
- Increase in anxiety and decrease in dpression
DA
-SNc for nigrostriatal
-Ventral tegmental and septal (along with GABA) mediated pleasure. Midbrain
+ Psychosis
-Depression and parkinsons
5-HT
- In gut and dorsal raphe (pons)
- Depression and aniety
Ach
Basal Meynert
-Alzhiemers huntingtons
+parkinsons relative, and REM
GABA
septal, nucleus acumbens for pleasure
-huntingtons and anxiety
BBB
Endothelial cells tight junctions and non fenestated
- BM
- Astrocyte foot processes
- Polar solutes cannot cross, glucose and AA need carriers
- Fenestrated at area postrema, OVLT, neuropohysis
- Destruction by trauma, tumor, infection can lead to vasogenic edema
Lateral Hypothalamus
- Destruction leads to anorexia and apathy
- Leptin will inhibit and lead to similar symptoms
- Normally mediates feelings of hunger and aggression
DM hypothalamus
- Destruction leads to agression and hunger (Craniopharyngoma possible cause)
- Leptin will stimulate (normaly mediates feelings of satiety)
Anterior
PANS, part of papez circuit
Posterior
SANS
Suprachiasmatic
-Circadian Ryhtms
Paraventricular and supraoptic
Neurons from the PP that secrete oxytocin and ADH. Production of hormones occurs in cell bodies in paraventricular and supraoptic hypothalamus
VPL
Input from sesnation of body, output to sensory cortex
VPM
Input from sensation of face, output to sensory cortx
VA/VL
-Input basal ganlia and cerebellum, output to motor cortex of cerebrum
MGN
-Input from superior olive and inferior colliculus, output to temporal lobe
LGN
-Input from CNII, vision. Output to calcarine sulcus of occipital lobe
Limbic
Emotions, Feelings, memory, etc
-Olfactory is part
Kluver Bucy
- HSV encephalopathy or strokes
- Bilateral lesions lead to docility, hyperphagia, hypersexuality
Foster Kenedy
-Meningoma or other destruction of olfactory tract and associated emotional liability. Damage to frontal lobe
Papez Circuit
-Hippocampus to mamlary bodies via the fornix. To the anterior hypothalamus to the cingulate gyrus ot the entorhinal cortex
Cerebellum
Inputs via the inferior peduncle (body) and middle peducnle (contralateral cortex) all sensation is from the ipsilateral side
- Output via the superior cerebellar peduncle. To VA/VL thalamus to contralateral motor cortex. Motion is to ipsilateral side
- All lesions will result in ipsilateral defect
Localizations
- Anterior is legs and posterior is upper body
- Vermal is balance and lateral is directed purposeful movements
- Floculonodular communicates with vestibular nuclei of CN8 and is impt for vertigo and nystagmus
Lesions
- anterior vermal commonly seen in alcoholics causes cerebellar ataxia, intention problems
- Posterior vemal is more commonly seen involving tumors of kids, upper body ataxia
- Lateral is commonly involved in stroke and can be seen involving problems with purposeful movement
- Floculonodular damage in a stroke will lead to nystagmus and vertigo
- All lesions will be ipsilateral. More important for stroke localization
Basal Ganglia
Control and process motion and cognition from cerebellum and cortex
- Cortical input with negative feedback on cortex
- Output is inhibitory via the Gpi/snr
- Input is dopaminergic from snr (parkinsons)
Striatum
Putamen (motor) and Caudate (cognition)
- D1 Gs receptor mediates direct pathway increasing motion
- D2 mediates inhibitory pathway (Gi)
Direct Pathway
-D1 leads to inhibition of Gpi/snr which is the inhibitory output. Net is loss of inhibition and action
Indirect Pathway
D2 leads to inhibition of STN which is normally excitatory onto snr/gpe. This leads to an increased action of inhibitory outputs and a decrease in motion
-D2 antagonist used in psychosis can cause tardive dyskinesia through this receptor
Parkinsons
- Characterized by loss of neurons in the snc that leads to a decrease of stimulation of the putamen and caudate.
- Dead neurons have lewy bodies composed of intracellular aggregates of alpha synuclein
- Leads to classic quartade of Bradykinesia, resting tremor, rigidity, and gait instability
Huntingtons
- Characterized by destruction of caudate nucleus due to AD trinucleotide repeat.
- Loss of Ach and GABA can lead to NMDA induced excititotoxicity
- Clinically will present as depression and choreoathetosis leading to death in midlife
Hemibalism
Infarction of STN which leads to loss of excitment to inhibitory snr/gpi leads to a net increase in motor activity
- Clinically will present as contralateral random flinging movements
- Infarction is due to disruption of flow in branches of posterior communicating artery
Wilsons Disease
- Mutation in ATPB7 involved in copper loading into cerruloplasm
- Leads to hepatoleticular degeneration
- Commonly see deposits in lenticular nuclei (putamen and globus pallidus)
Kernicterus
-Elevated bilirubin, commonly precipitates in BG
Essential Tremor
- Exacerbated by static posture, not intention tremor and is present at rest
- Treat with beta blockers
Resting Tremor
-Parkinsons
Intention Tremor
Think of cerebellar injury, especially lateral cerebellum
MPTP
Street drug that can cause symptoms of parkinsons
VA/Premotor
Communication generally between VA and premotor in frontal lobe
VL-primary motor
Most outputs go to primary motor cortex
Brocas area
- Dominant (left hemisphere in frontal lobe, supplied by MCA)
- Speaking aphasia
Arcuate fasiculus
Connects the two
-Each work fine idependently, but can’t repeat
Wernickes Area
- Auditory sensory and association
- Damage, MCA leads to fluent aphasia
- Temporal lobe posterior to sylvian fissure
Primar Auditory
Temporal lobe, receieves input from MGN
Fronatl Eye fields
Damage leads to looking towards lesion, MCA
PPRF
Midbrain, lesion leads to looking away from lesion
-Horizontal palsy with lack of saccades. Connects to superior colliculus and vestibular
Homunculus
- Legs are aterior cerebral
- Hand is MCA and loctate at superior frontal lobe
- Mouth and tongue is lateral frontal lobe MCA
Amygdala
- Damaged by HSV-1 encephalitis, leads to Kluver Bucy
- Hyperorality, phagia, sexuality
Frontal Lobe
Damage leads to loss of concentration and inhibition
Right, non dominant parietal
-Spatial neglect on the nondominant side (anosognosia)
RAS
- Midbrain, Ach and NE with locus ceruleus and septal etc
- Coordinates arousal status
Mamillary Bodies
- Wernicke Encephalopathy
- Hemorrhagic necrosis leading to opthalmoplegia, ataxia, anterograde amnesia (confabulations and confusion)
- Lack of thiamine
Central Pontine Myelinolysis
- Too rapid of correction of Na leads to osmotic necrosis of central pons
- Leads to paralysis, dysarthria, and loss of conciousness can lead to locked in syndrome
Gerstmann’s
-Damage to angular gyrus or superior parietal lobule leads to acalcula and agraphia on dominant side
Watershed Areas
-Upper leg and arm and higher order visual processing
Regulation
- Relies almost exclusively on CO2
- Theraputic hyperbetalation leads to constriction and decreased cerebral blood flow and decreased cerebral edema
Vulnerable spots to global ischemia
- Cerebral layers 3,5,6
- Perkinje Cells of cerebellum
- Hipocampal pyramidal cells
Infarcts
Pale: Thrmobus, atheroscleososis, most common at branch points
- Red: Embolus, A fib
- Lacunar: HTN and hyaline arteriosclerosis