Functional Flashcards
In the neurosurgical management of Parkinson disease, lesioning of the ventrolateral nucleus of the thalamus has proved especially beneficial in controlling which of the signs and symptoms of the disease?
Tremor
Focal midbrain atrophy is most commonly seen on MR imaging of the brain in a patient with which of the following neurological disorders?
Focal midbrain atrophy with relative sparing of the pons, sometimes referred to as the “Hummingbird sign” or “Penguin sign” is characteristic of progressive supranuclear palsy (PSP).
PSP is a neurodegenerative disease characterized by Parkinsonian features, postural instability, and supranuclear vertical gaze palsy.
Pathologic specimens exhibit neurofibrillary tangles composed of misfolded tau protein.
Midbrain atrophy is specific to PSP and can be diagnostically useful in distinguishing PSP from idiopathic Parkinson’s disease and multiple systems atrophy, which may have overlapping symptoms.
Enkephalins and GABA are the main neurotransmitter from:
putamen to GPe
substance P and GABA are the main neurotransmitters from:
GPe to GPi
Glutamate is the main neurotransmitter from:
cortex to putamen and STN
STN to GPe, GPi, and SN
Thalamus to cortex and putamen
serotonin and cck are the main neurotransmitters from:
dorsal raphe nucleus to SN
serotonin and enkephalins are the main neurotransmitters from:
dorsal raphe nucleus to caudate
projections to and from the medial dorsal nucleus of the thalamus:
input to MD are: prefrontal cortex, GP, amygdala, temporal cortex and SN
output: prefrontal cortex
DBS target for dystonia:
GPi
DBS target for bradykinesia and rigidity (parkinsons):
STN
input and projections of LP nucleus of thalamus:
LP nucleus of thalamus receives input from area 5 and projects to areas 5 and 7
What is the main cortical input to the hippocampus?
entorhinal cortex through the alvear (to CA1) or perforant (to dentate gyrus and CA3) pathways
What is the best treatment for drop attacks?
corpus callosotomy
prevents spread of seizures to the contralateral hemisphere
Risks of disconnection syndrome; therefore, the posterior part of the corpus callosum (splenium) should be preserved
Inclusion bodies (all intracytoplasmic) type and disease:
hirano bodies: alzheimers
lafora bodies: lafora disease
pick bodies (stain with silver): picks disease
lewy bodies: parkinsons
bunina bodies: ALS
type of inclusion bodies found in melanin cells?
marinesco bodies (normal)
contain ubiquitin
Sodium valproate (AED) works by:
Increasing GABA
benzodiazepine and barbiturates (AEDs) work by:
stimulating GABAa receptors
phenytoin and carbemazepine (AED) work by:
decreasing sodium conductance by blocking sodium channels
DBS of the periaqueductal gray can result in (side effects):
diplopia, oscillopsia, fear, and anxiety
When targeting STN for Parkinson’s disease, if the DBS electrode is too:
Medial → III n → diplopia, ipsilateral eye adduction.
Lateral and anterior → internal capsule → contralateral contractions, contralateral gaze deviation.
Posterior → medial lemniscus → contralateral paresthesias.
Deep (ventral) → substantia nigra → fear, depression
When targeting GPi with DBS for Parkinson’s disease or dystonia, if the electrode is too:
Medial and posterior → internal capsule → contralateral contractions.
Deep → optic tract → phosphenes (flashes of light) in the contralateral visual field.
Lateral and anterior → GPe, putamen → no effect.
What forms the thalamic fasciculus (FFH1)? What is the main neurotransmitter?
thalamic fasciculus (FFH1) is formed by the lenticular fasciculus (FFH2) and the ansa lenticularis. It projects from the GPi to the thalamus using GABA. It also carries dentate nucleus projections to the thalamus
Which thalamic nuclei project to the cingulate gyrus and what are the inputs?
Anterior nuclear group
receives input from the fornix and the mamillothalamic tract
dorsal anterior cingulate cortex (dACC) is thought to be responsible for which type of pain?
affective
What are the different targets for DBS and what are they treating?
Parkinsonism → STN
essential tremors → Vim
dystonia → GPi
nucleus accumbens septi → obsessive-compulsive disorder (OCD)
subcallosal cingulate gyrus → depression.
What are the two neurotransmitters in the dorsal horn that transmit pain?
substance P (chronic pain, burning, slow) and glutamate (acute pain, sharp, fast) via C and Adelta fibers, respectively
Marchiafava–Bignami disease: It was first described in Italian men drinking inexpensive red wine. Symptoms include dementia, depression, apathy, and delusions. What are the CNS manifestations?
It is rare, and causes demyelination and necrosis of the genu and body of the corpus callosum.
CNS manifestations and symptoms of central pontine myelinolysis?
demyelination and necrosis with preserved axons and neurons and absence of inflammatory cells. Symptoms include quadriparesis, hyperreflexia, seizures, coma, and pseudobulbar palsy.
Black widow spider venom: symptoms, mechanism, treatment
This depletes the presynaptic ACh stores into the neuromuscular junction, causing cramps and spasms followed by weakness. Treatment is with Ca2+ gluconate and MgSO4.
Huntington’s disease: onset, inheritance/chromosome, mutation, symptoms, treatment
Onset in the 30s, with survival 15–30 years more.
autosomal dominant on chromosome 4 with no sex predilection
trinucleotide repeat disorder of CAG
Symptoms begin with personality changes followed by subcortical dementia (no aphasia, agnosia, or apraxia) and choreiform movements (affects hands and face first)
atrophy mostly of the caudate (with boxcar ventricles) more than the putamen, GP, and cortex. Medium spiny type 1 neurons are affected first and aspiny neurons are spared. There is decreased GABA and ACh and increased NE and somatostatin.
Haloperidol (2–10 mg/day) may be used to treat the athetosis, with low doses and frequent drug holidays to decrease the risk of tardive dyskinesia
primary basal ganglia and cerebellar blood vessel calcification (sometimes also dentate nuclei) associated with renal disease or decreased parathyroid hormone.
Fahrs disease
Striatonigral degeneration: symptoms, CNS manifestations
Symptoms include rigidity and akinesia (Parkinson-like symptoms) with syncope. There are atrophic and brown putamen and depigmented SN as well as decreased neurons in the putamen, caudate, and SN. There are no Lewy bodies or neurofibrillary tangles.
Progressive supranuclear palsy: onset, symptoms, response to L-DOPA, CNS manifestations, type of neurofibrillary tangles
Onset of 50–60 years and death within 1–12 years with male predominance
Symptoms include deterioration of intellect, vision, speech, and gait, with vertical gaze palsy, loss of voluntary eye movements and opticokinetic nystagmus, decreased oculocephalic reflexes, pseudobulbar palsy, and axial rigidity without tremor
poor response to L-DOPA
atrophy of the midbrain, superior colliculus, and subthalamic nuclei with ventricular dilation and decreased neurons in the GP, SN, and various brainstem nuclei
neurofibrillary tangles are different than the Alzheimer type (i.e., globose versus flame-shaped).
Olivopontocerebellar atrophy: onset, inheritance, symptoms, CNS manifestations
Onset is at 15 years with sporadic, recessive, and dominant inheritance
Ataxia of the lower limbs occurs first
atrophy of the pons, middle cerebellar peduncle, inferior olive, and cerebellar cortex. It is associated with Parkinson’s syndrome.
Strokes in children are caused by:
Fabry disease, homocystinuria.
Caudate subcomponents:
Head: contiguous with the anterior perforated substance.
Body: separated from the thalamus by the stria terminalis and the terminal vein.
Tail: in the roof of the temporal horn near the amygdala.
Nucleus accumbens septi: located where the caudate and putamen meet anteriorly.
striatum definitions:
Lentiform nuclei = putamen + GP.
Corpus striatum = neostriatum + paleostriatum (caudate, putamen, GP).
Neostriatum (or striatum) = caudate + putamen.
Striatum input fibers:
Corticostriate fibers (most important input) which travel from:
Area 4 → bilateral putamen.
Premotor cortex → ipsilateral caudate and putamen.
Prefrontal cortex → caudate.
Amygdalostriate fibers:
Amygdala → caudate and putamen.
Thalamostriate fibers, which travel from:
Intralaminar CM nucleus (the largest intralaminar nucleus) → putamen.
Parafascicular nucleus (PF) → caudate.
Nigrostriatal fibers, which travel from:
SN → caudate and putamen (inhibitory dopamine).
Raphe nucleus sends inhibitory fibers (serotonin).
Striatum ouput:
Striatonigral fibers: head of caudate → substantia nigra pars reticulata (SNpr).
Striatopallidal fibers: caudate/putamen → GP interna (inhibitory, GABA).
Nigrothalamic fibers: terminate in VA, VLm, MD (GABA).
Pallidosubthalamic fibers:
LGP → ST.
MGP → stria medullaris → lateral habenula.
GP → VA, VL, and CM.
