Neurodegenerative Diseases Practice Flashcards

These flashcards cover the key vocabulary, anatomy, pathophysiology, and treatments for various neurodegenerative and neurological disorders discussed in the lecture.

Caudate Nucleus

A subcortical nucleus that, together with the putamen, forms the striatum, serving as the primary input zone of the basal ganglia.

Substantia Nigra

A midbrain structure containing dopamine-producing neurons characterized by a dark color from neuromelanin.

Hippocampus

The limbric structure responsible for encoding and indexing explicit memory (facts and events) via Long-Term Potentiation (LTP).

Fornix

A nerve tract through which the hippocampus sends signals directly to the mammillary bodies of the hypothalamus.

Long-Term Potentiation (LTP)

A process where repeated neural firing strengthens synaptic connections, turning short-term neural activity into lasting structural changes.

Amyloid-Beta Plaques

Clusters of protein fragments that accumulate outside neurons in Alzheimer's disease, blocking synaptic transmission and triggering inflammation.

Neurofibrillary Tangles (Tau)

Twisted fibers of tau protein that accumulate inside neurons, causing the collapse of internal structural scaffolding and transport lines.

Entorhinal Cortex

The anatomical main doorway into the hippocampus and the initial target of tau pathology in Alzheimer's disease.

Lecanemab

A first-line monoclonal antibody disease-modifying therapy (DMT) that clears amyloid pathology to slow cognitive decline in early AD.

Donepezil

An Acetylcholinesterase (AChE) inhibitor used as first-line symptomatic treatment for mild to moderate Alzheimer's disease.

Memantine

A second-line/adjunctive NMDA receptor antagonist used in moderate to severe AD to prevent calcium-mediated excitotoxic cell death.

Basal Forebrain

The primary producer of acetylcholine ($ACh$) which is severely damaged in Alzheimer's disease, leading to lower levels of essential synaptic chemical lubricant.

Direct Pathway

The "GO" motor signaling pathway activated when dopamine binds to striatal $D_1$ receptors, causing hyperpolarization of the $GPi/SNr$ and lifting the brake on the thalamus.

Indirect Pathway

The "NO-GO" motor pathway suppressed when dopamine binds to $D_2$ receptors, which normally inhibits the motor thalamus via the $GPe$ and $STN$.

Medium Spiny Neurons (MSNs)

Striatal neurons that release GABA; they either express $D_1$ receptors ($dMSNs$) for movement initiation or $D_2$ receptors ($iMSNs$) for movement cessation.

Carbidopa

An inhibitor of peripheral aromatic L-amino acid decarboxylase ($AADC$) that prevents the premature breakdown of levodopa outside the brain.

Pramipexole

A dopamine-2 ($D_2$) agonist used as first-line monotherapy for younger Parkinson's patients to spare them from levodopa-related motor complications.

Rasagiline

A Monoamine oxidase type B ($MAO-B$) inhibitor that extends the half-life of dopamine by preventing its enzymatic breakdown.

Entacapone

A $COMT$ inhibitor used as an adjunct to levodopa to prevent its peripheral degradation and smooth out "off" time in Parkinson's disease.

$\alpha$-Synuclein

The protein whose abnormal intracellular aggregation is the primary pathological hallmark of both inherited and idiopathic Parkinson's disease.

Bradykinesia

A classic motor symptom of Parkinson's disease characterized by slowness of movement.

Nucleus Basalis of Meynert

A specific region within the basal forebrain that undergoes marked neurodegeneration in Alzheimer's, leading to a significant acetylcholine deficit.

Micrographia

A clinical motor sign in Parkinson's disease where a patient's handwriting becomes noticeably smaller.

Trigeminovascular System (TGVS)

The core neural network involving the trigeminal ganglion whose activation centers the pathophysiology of primary headaches.

Substance P

A neuropeptide that is the primary driver of plasma protein extravasation ($PPE$) and mast cell degranulation in headache disorders.

Vasoactive Intestinal Peptide (VIP)

A potent vasodilator neuropeptide that mediates cranial autonomic symptoms ($CAS$) like tearing and nasal congestion in cluster headaches.

Cortical Spreading Depression

An electrical wave in the brain that can trigger the trigeminal ganglion to fire action potentials centrally and peripherally during migraine aura.

Cluster Headache

An extremely severe, strictly unilateral headache characterized by sharp, stabbing pain and brief frequency ($15$ to $180$ minutes).

Verapamil

A calcium channel blocker routinely used for the long-term prophylactic management of cluster headaches.

Propranolol

A beta-blocker used as a prophylactic treatment for migraines to suppress cortical spreading depression.

Paroxysmal Depolarizing Shift (PDS)

The hallmark cellular mechanism of seizure onset characterized by a giant, abnormal electrical event at the single-neuron level.

Tonic Phase

A seizure phase lasting $10$ to $20$ seconds where all muscles contract, eyes roll back, and an "epileptic cry" may occur.

Clonic Phase

A seizure phase lasting $30$ to $90$ seconds involving synchronous, violent rhythmic jerking of the limbs and potential tongue biting.

Atonic Seizures

Generalized seizures also known as "drop attacks" that involve a sudden, complete loss of muscle tone lasting less than $2$ seconds.

Ethosuximide

A T-type calcium channel blocker that is the first-line treatment for generalized non-motor (absence) seizures.

Benzodiazepines

Positive allosteric modulators of the $GABA_A$ receptor that increase the channel opening frequency to treat acute status epilepticus.

Barbiturates

$GABA_A$ receptor modulators that increase channel opening duration and can antagonize AMPA/Kainate glutamate receptors directly.

Status Epilepticus

A medical emergency defined by a seizure lasting $\ge 5\,minutes$ of continuous activity or multiple seizures without recovery.

End-Plate Potential (EPP)

A localized, graded depolarization of the motor end-plate caused by a massive influx of $Na^+$ through nicotinic acetylcholine receptors ($nAChR$).

Acetylcholinesterase (AChE)

The enzyme that terminates signaling at the neuromuscular junction by hydrolyzing acetylcholine into choline and acetate in $< 1\,ms$.

Multiple Sclerosis (MS)

An inflammatory autoimmune disorder of the central nervous system characterized by the destruction of oligodendrocytes and myelin.

Saltatory Conduction

The rapid jumping of electrical signals between nodes of Ranvier, which is lost during demyelination in MS.

Amyotrophic Lateral Sclerosis (ALS)

A progressive neurodegenerative disease causing the death of upper and lower motor neurons and subsequent muscle atrophy.

EAAT2

The astrocytic glutamate transporter that is lost in ALS, leading to synaptic glutamate accumulation and excitotoxic $Ca^{2+}$ influx.

Riluzole

A medication that modestly extends survival in ALS by blocking voltage-gated $Na^+$ channels and enhancing astrocytic glutamate re-uptake.

Edaravone

A free radical scavenger that neutralizes reactive oxygen species ($ROS$) to slow functional decline in select ALS patients.

Baclofen

A selective $GABA_B$ receptor agonist used as first-line oral pharmacotherapy to reduce muscle spasticity.

Tizanidine

A central $\alpha_2$-adrenergic receptor agonist that reduces spasticity by increasing presynaptic inhibition of motor neurons.

Oxybutynin

An antimuscarinic agent that blocks $M_2$ and $M_3$ receptors on the detrusor muscle to treat spastic bladder in MS.

Optic Neuritis

An MS symptom involving visual loss often treated with high-dose intravenous corticosteroids to hasten recovery rate.

Sialorrhea

The clinical term for excess drooling in ALS, managed with anticholinergics like glycopyrrolate or atropine.

Pedunculopontine Nucleus (PPN)

A brainstem area containing cholinergic neurons whose degeneration in PD leads to gait freezing and postural instability.

REM Sleep Behavior Disorder (RBD)

A prodromal PD symptom where loss of brainstem cholinergic tone causes patients to physically act out their dreams.

Dyskinesia

Involuntary, erratic movements that often occur as a side effect or complication of long-term Levodopa therapy.

Stevens-Johnson Syndrome (SJS)

A severe, potentially fatal skin rash that is a known idiosyncratic risk of sodium channel blockers like Lamotrigine.

Mirabegron

A $\beta_3$-adrenergic agonist used for neurogenic detrusor overactivity that relaxes the bladder during the storage phase.

Natalizumab

A monoclonal antibody for MS that blocks $\alpha_4\beta_1$ and $\alpha_4\beta_7$ integrins to prevent leukocytes from crossing the blood-brain barrier.

Tau Pathology Spread

In Alzheimer's, this starts in the entorhinal cortex, moves to the hippocampus, and eventually covers the broader neocortex.

Papez Loop

The neural circuit through which the hippocampus replays firing patterns to the neocortex during slow-wave sleep for memory consolidation.

Glutamate

The primary excitatory neurotransmitter whose imbalance/excess leads to excitotoxicity and seizures through NMDA and AMPA receptors.