neurodegenerative Flashcards

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1
Q

Prion disease

A

Prion disease is rare type of neurovegetative disease caused by accumulation of misfolded proteins and loss of synapse

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2
Q

Spongiosis in prion disease

A

Spongiosis is a term for holes in brain tissue

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3
Q

scrapie prion disease

A

Affected animals and develops a loss of coordination, uncontrollable itch

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4
Q

BSE prion disease

A

a type found in cows, BSE was spread to other animals the number of cases was rapidly amplified when infected carcasses were processed into cattle feed.

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5
Q

CJD prion disease

A

most common human type that causes a lot of loss of brain tissue
Life expectancy is around 4 months

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6
Q

Symptoms of CJD prion disease

A

Symptoms include rapidly progressing dementia, development of movement disorders such as tremor and rigidity

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7
Q

vCJD prion disease

A

longer duration
only affected young people
prolonged neuropsychiatric syndrome

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8
Q

3 forms of prion disease

A

Sporadic prion disease - here an unknown stimulus results in the formation of PrPSc. The most common type.

Inherited, or familial, prion disease - results from a genetic abnormality in the Prnp gene, which encodes for the prion protein, resulting in formation of abnormal prion protein.

Acquired prion disease - the misfolded protein is taken in from an outside source; such as the development of variant Creutzfeldt-Jakob disease (vCJD) due to the ingestion of bovine prions or Kuru.

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9
Q

iatrogenic transfer prion disease

A

the accidental spread of prions between humans during medical or surgical treatment

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10
Q

PrPsc prion disease

A

PrPsc are misfolded protein
There is a cycle of proliferation, in which PrPSc accumulates and recruits PrPC
As the brain becomes depleted of PrPC, this stimulates synthesis of more, which in turn means more substrate for pathological conversion.

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11
Q

PrPC vs PrPsc

A

PrPc changes to PrPsc
two isoforms of PrP have identical primary structure but different secondary and tertiary structures.
PrPsc is harder to be broken down due to its stronger bonds

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12
Q

Prnp

A

Prnp codes for the PrP and knockout in mice still caused normal function in mice
Only impaired LTP and reduced after hyperpolarisation potentials.
PrP may have a role in modulation of neuronal excitability.
Can effect Prpsc conversion rate

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13
Q

treatment of Prion disease

A

Treatment only prolongs life a bit but still no cure
Whether in humans or animals, the disease is always fatal
Drug-DBM and trazodone

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14
Q

Largest risk factor of Alzheimer’s

A

Age

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15
Q

Dementia affects what

A

Issues occur with memory

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16
Q

What does dementia mini mental state test for

A

orientation, registration , attention, recall and language

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17
Q

Types of dementia

A

Alzheimer’s disease (AD): 50-75%

Vascular dementia (VD): 20%

Dementia with Lewy body (DLB): 15-20%

Frontotemporal dementia (FTD): 2%

Rare causes: Parkinson’s disease dementia (PDD), Huntington’s disease (HD), Prion disease, others.

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17
Q

Genetic risk factor of dementia

A

most cases are rare but can be inherited (<5%) e.g. mutations in the amyloid precursor protein (APP) and presenilin genes (PSEN1, PSEN2).

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18
Q

Dementia and cardiovascular disease

A

smoking and diabetes increase risk. Exercise decreases risk.

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19
Q

2 types of misled protein in dementia

A

Amyloid B plaques: used normally for synaptic function and BBB protection
Neurofibrillary Tangles: used normally for DNA protection and dendritic development

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20
Q

APP

A

APP has multiple cleavage sites to for different isomers
Once cleaved into its many forms, these have specific tissue expression and multiple functions including synapse regulation, synaptic plasticity and iron transport.

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21
Q

Non-amyloidogenic pathway

A

Used for neuroprotection,
Neurite outgrowth, Neural stem cell proliferation ,Enhances LTP
Use of a-secretase to snip parts of APP and amyloidogenic peptides release sAPPa

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22
Q

Amyloidogenic pathway

A

Mainly uses β-secretase in the brain(BACE1) to snip APP
Left with 3 products:
sAPPβ :Lacks most neuroprotective effects of sAPPα
Aβ:Varies in length, found in alzhiemer patients
AICD:Translocated to the nucleus & activates transcription of target genes such as p53, GSK3β & EGFR.

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23
Q

Treatment of dementia

A

have tried knocking out BACE1 but this leads to hypomyelination and caused seizures so acyetholinesterases are used

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24
Q

Amyloid B

A

play a central role in Alzheimer disease
Secondary structure - predominately alpha-helical but see global conformational rearrangement and formation of beta-sheet structure by fibrillization

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25
Q

Treatment in AD through Amyloid beta

A

Immunization(vaccination shows some help) via
BACE1 inhibitors

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26
Q

Aducanumab medication in Alzheimer’s

A

an antibody therapy that targets amyloid beta protein
Causes antibody to unbundle plaques or be to be engulfed by phagocytosis
Can lead to very bad effects and may decrease quality of life

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27
Q

Neurofibrillary tangles in Alzheimer’s

A

Occur from Tau proteins
Tau proteins is a family of microtubles associated proteins and promote stability of microtubule network
Disorder in Tau become hyperphosphorylated and form intraneuronal aggregates.

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28
Q

Tau microtubule binding

A

6 isoforms of Tau all with different binding sites
four microtubule-binding repeats(4R) promote microtubule construction(more likely to misfold)
three microtubule-binding repeats (3R)worse at promoting microtubule stability

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29
Q

synapse loss in AD

A

Synapse loss occurs with aging but with advancing AD synapses are disproportionately lost relative to neurons.
reduction in dendritic branch length and complexity
down regulation of postsynaptic proteins such as PSD-95

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30
Q

synaptic plasticity in AD

A

Synaptic plasticity fails with AD
Experiment done with mice cultured with higher temperature produced more synapses per area after 3 months

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31
Q

Astrocytes and microglia in AD

A

Astrocytes and microglia help to protect against Alzheimer’s
neuroprotective as it aims to clear cell debris, phagocytose dead cells, and release neurotrophic factors.

In later disease – persistence of damaging stimuli means microglia are chronically activated & release inflammatory cytokines that drive neurotoxicity and neurodegeneration

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32
Q

Types of astrocytes

A

A1 astrocytes are neurotoxic – they are stimulated by activated microglia release of (IL-1α), (C1q) and TNF-α. They can then activate β & γ secretase activity.They can also cause secretion of neurotoxins, loss of synaptogenesis and neuronal death

A2 astrocytes are neuroprotective – they upregulate several neuroprotective factors that promote synaptic repair

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33
Q

Genetic risk factor in AD

A

APOE ε4 allele is one of the highest risk factors

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34
Q

How is dopamine synthesised in basal ganglia

A

amino acid tyrosine is converted to L-dopa then L-dopa is decarboxylated to form dopamine.

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35
Q

Dopamine rich areas in the brain

A

localised to the substantia nigra and the ventral tegmental area in the midbrain

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36
Q

Dopamine pathways

A

mesocortical; mesolimbic; and the nigrostriatal pathway

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37
Q

Outline Basal ganglia structures

A

the striatum, which includes the caudate nucleus and the putamen,

the globus pallidus (GP) which is divided into two segments, the internal (GPi) and external parts (GPe),

subthalamic nucleus

substantia nigra

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38
Q

substantia nigra

A

divided into two parts, the reticular part (SNpr)-essential for movement coordination and initiation and the compact part (SNpc)-This region contains GABA-producing neurons. GABA is an inhibitory neurotransmitter that helps to regulate movement.

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39
Q

substantia nigra dysfunction causes which diseases

A

Parkinson’s disease, Huntington’s disease, and progressive supranuclear palsy

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40
Q

Basal ganglia

A

important in planning and modulation they switch pathways to determine motor program by using muscle tone, muscle length, speed, and strength of the movement by using the pyramidal system

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41
Q

Where do basal ganglia receive input

A

Caudate nucleus
Putamen
Nucleus accumbens

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42
Q

Output in basal ganglia

A

send information to the thalamus and internal segment of the globus pallidus (GPi), & substantia nigra pars reticulata (SNr)

43
Q

Intrinsic nuclei in basal ganglia

A

The Intrinsic nuclei are located between the input and output nuclei in the relay of information

44
Q

Limbic loop in basal ganglia

A

Involved in behaviour and emotion response

45
Q

Oculomotor loop in basal ganglia

A

connects cortical regions involved in visual attention and eye movement planning

46
Q

Cognitive loop in the basal ganglia

A

area relies on DA input from the SubstNigra – together with motor loop, considered to be involved in procedural learning and decision making

47
Q

Thalamus in the basal ganglia

A

provides the feedback loop between the cortical areas and the BG

48
Q

the motor loop in basal ganglia

A

dysfunction of this loop that leads to the neurological disorders of Huntingtons & Parkinsons.
The motor loop arises from the primary, premotor and supplemental motor cortex, and the primary sensory cortex.

49
Q

direct and indirect pathway in basal ganglia

A

DIRECT PATHWAY which facilitates movement and the INDIRECT PATHWAY which inhibits movement.
Activation and inhibition leads to smooth voluntary movement

50
Q

Indirect pathway in basal ganglia

A
  • In the indirect pathway, Glutamatergic input from the motor and sensory cortex excite the GABA inhibitory neurons in the Putamen which release GABA to the GPe which inhibits the neurons in the GPe.
51
Q

Huntington’s disease in basal ganglia

A

slow progressive neurodegenerative disease, in which there is a cognitive, motor and psychiatric deterioration over 20-30 year period. hyperkinetic disorder and results from dysfunction of the striatum. Hyperkinetic means abnormally increased movement

52
Q

Autosomal dominant hereditary disease in the basal ganglia

A

expansion of CAG repeat(CAG codes for amino acid Glutamine, these repeats add an abnormally long string of Glutamine to the protein which is thought to aggregate in the neurons, a higher number of CAG repeats in the huntingtin gene

53
Q

Aggregates of CAG in basal ganglia

A

Aggregates cause mitochondrial dysfunction; neuronal stress; excitotoxicity & neuroinflammation

54
Q

main pathological features in HD from basal ganglia

A

The main pathological features in HD are drastic loss (degenration)of (mostly) medium spiny neurons in the striatum &raquo_space; atrophy of the striatum

55
Q

symptoms of Huntingtons disease

A

loss of executive function

depression

irritability

cognitive decline

hallucinations

56
Q

Parkinson’s disease in basal ganglia

A

linked to the motor loop of the BG is Parkinsons
It is a hypokinetic disorder linked with dysfunction of the SubNigra.

57
Q
A
58
Q

Phases of issues with basal ganglia in Alzheimer’s

A
  • Prodromal :- range of non-motor symptoms can last up to 20 years: constipation, hyposmia, sleep disorder, depression, anxiety, cognitive impairment – all of which can so easily be classified as completely separate to PD as they predate the classical symptoms of PD seen in the
  • Clinical phase of tremor, rigidity, slowness of movement, together with the continuing symptoms of the prodromal phase – mild memory and thinking problems, sleep problems, pain, depression, anxiety
59
Q

Lewy body

A

lewy bodies are abnormal aggregates of protein that develop inside nerve cells . They are found in the brains of people with Parkinson’s disease, dementia with Lewy bodies (DLB)

60
Q

Areas of the brain associated with lewy body

A

Associated with lewy bodies in the subcortical and cortical regions

61
Q

alpha synuclein in Lewy body

A

Lewy bodies contains protein alpha synuclein(helps in synapses)
Lewy body disform the cell as they push things away from the cell
A-synuclien helps with vesicle trafficking

62
Q

types of lewy body

A

Brain stem:Has a halo
Cortical: Less well defined

63
Q

FTLD

A

damages frontal and temporal disease
Early onset of 45-64

63
Q

treatment of Lewy body

A

Treatment with cholinesterase is used for delirium but antipsychotic is needed to be avoided
Acetylcholine is needed to be boosted in LD
Donepezil is a reversible cholinesterase inhibitor

64
Q

types of FTLD

A

Primary progressive aphasia (PPA): This type of FTD is characterized by problems with language.
FTD with motor neuron disease (FTD-MND): This type of FTD is characterized by symptoms of both FTD and amyotrophic lateral sclerosis (ALS), a motor neuron disease that causes muscle weakness and wasting.

65
Q

TDP-43 in FTD

A

This protein is normally found in healthy neurons, but in FTD, it clumps together and forms toxic aggregates.

66
Q

other factors that affect FTD

A

Oxidative Stress: An imbalance between free radicals and antioxidants can damage neurons.
Inflammation: Chronic inflammation in the brain
Environmental Factors: Exposure to toxins or head injuries

67
Q

Stroke types

A

Ischemic Stroke (most common): A blood clot blocks an artery supplying blood to the brain.
Hemorrhagic Stroke: A weakened blood vessel ruptures and bleeds into the brain tissue.

68
Q

primary impacts of stroke

A

Brain cell death: Deprived of oxygen and nutrients, brain cells die in the affected area
Disruption of neural circuits: Brain regions rely on interconnected networks of neurons. Stroke damage can disrupt these circuits

69
Q

Types of neurorehabilitation

A

Physical therapy
Occupational therapy
Speech therapy
Cognitive rehabilitation

70
Q

Neuroplasticity and Stroke Recovery

A

Relearning skills: By practicing lost skills, the brain can strengthen existing neural connections or form new ones to compensate for damaged area
Promoting growth factors

71
Q

Highest priority in neurorehabilation

A

Arm and hand function is by far the highest priority

72
Q

Monkey experiment into neurorehabilitation

A

Rasta plot used on a monkey and one neurone is measured and every time the monkey fires action potential there is a pop
Decoding can predict the direction the monkey is going to move

73
Q

Corticospinal tract in stroke

A

Corticospinal tract is a major pathway that connects the primary cortex to the muscle for movement
Stroke can damage the CST, disrupting the communication between the brain and muscles causing weakness or paralysis on one side

74
Q

Therapy for Corticospinal tract dysfunction

A

Physical therapy to improve movement control and coordination.
Electrical stimulation techniques to enhance neural activity.
Constraint-induced movement therapy to encourage use of the affected side

75
Q

Decussates in corticospinal tract

A

Decussates means neurones crosses to the other side of the body from the brain stem cross to the other side

76
Q

Timing of stroke recovery

A

Largest increase in recovery is in the first 3 months

77
Q

Types of learning for recovery

A

Skill Re-learning-learning lost skills like walking, talking, or using your arm through repetitive practice and targeted exercises
Implicit Learning-This unconscious form of learning involves gradual improvements through repeated exposure or experience
Cognitive Learning

78
Q

Reinforcement learning in stroke

A

use the non dominant hand to learn ,the frequency with reward will determine the action, constraint induced movement is based of reinforming learning, there can be plasticity that connect muscle groups together

79
Q

motor sequence learning

A

Motor sequence learning-motor action is performed with higher spatial and temporal accuracy

80
Q

Multiple sclerosis

A

Attacks myelin sheath in the brain and spinal chord causing inefficient transmission

81
Q

Types of MS

A

Clinically Isolated syndrome
Relapsing syndrome-characterized by episodes of worsening symptoms (relapses) followed by periods of recovery
Secondary progressive MS
Primary progressive MS-a steady worsening of symptoms from the outset
Primary relapsing MS

82
Q

Symptoms of MS

A

Optic neuritis-inflammation of an optic nerve, causing blurred vision.
Uhthoff’s phenomenon- increased temperature causes fatigue, pain, balance, weakness,
Lhermitte’s phenomenon- when the neck is moved in the wrong way a electrical shock in the body

83
Q

Microphage and microglia formation in MS

A

Microphage and microglia formation causes oxidative stress and nitrous oxide which leads to neuronal mitochondrial dysfunction

84
Q

MS on the CNS

A

MS only affects the CNS therefore Specific antigens must be for the CNS
Myelin specific T cells affects this
Specific bacteria and viruses triggers these T cells

85
Q

Risk factors for MS

A

Increased MS to temperate region
Environmental risk factors
Sunlight – Vitamin D
Diet – obesity in early life
Low Vit. D + smoking = increased risk
Virus / infection exposure
HLA gene DRB1

86
Q

treatment of MS

A

Drug treatment destroys b cells -Ocrelizumab
Ocrelizumab & Natalizumab more effective
Relapse reduced or controlled
Disability symptoms stabilized or improved
Westernised diet is a factor in MS

87
Q

TBI

A

Executive functions get disrupted in TBI meaning thinking gets distorted

88
Q

Measurement of TBI

A

Mild to severe TBI rated via Glasgow coma scale

89
Q

Primary injury phase in TBI

A

Primary injury phase causes damage to the brain that cannot be undone and has highest levels of glutamine

90
Q

Focal TBI

A

Focal TBI happens in one area of the brain high glutamine causes higher levels of calcium which all lead to downstream factors which lead to cell death

91
Q

Severity of TBI

A

Mild TBI (mTBI): Most common type, with symptoms like headaches, dizziness, and brief confusion.
Moderate TBI Longer periods of unconsciousness, memory problems
Severe TBI: Prolonged coma, seizures, and significant cognitive and physical impairments.

92
Q

primary and secondary injury in TBI

A

Primary injury: Immediate damage to brain cells at the impact site, including tearing, shearing, and bleeding.
Secondary injury: A cascade of events triggered by the primary injury, including inflammation, oxidative stress, and cell death in areas beyond the initial impact.

93
Q

Remylination in TBI

A

Sub acute stage in first 3 months can be remyelinated

94
Q

Blood flow in TBI

A

TBI reduces blood flow in the brain hypothermia

95
Q

Acute TBI

A

Acute TBI usually causes metabolic and mitochondrial dysfunction
Chronic causes neurodegenerative processes

96
Q

Areas of neuronal loss in TBI

A

Grey matter loss is in the hippocampus and prefrontal motor cortex in TBI

97
Q

CTE

A

CTE occurs from the repetitive head impacts
Causes chronic depression leading to aggression, suicide and mood swings caused by degradation

98
Q

inhibiting CTE affects

A

Inhibit CTE affects by using anti inflammatory and anti exotoxins

99
Q

Interneurones in TBI

A

Interneurons are extremely vulnerable to death after TBI

100
Q

Biomarkers in TBI

A

GFAP ↑ with TBI
NfL ↑ with TBI
Synaptophysin ↓

101
Q

Tau in CTE

A

abnormal accumulation of a protein called tau inside brain cells, particularly neurons.

102
Q

How do prions cause cell death

A

By affecting membranes and shortening the dendritic spines that the cells use to transmit signals to each other

103
Q

oxidative stress and misfolding proteins

A

Oxidative stress can damage proteins and increase misfolding risk

104
Q

FTD affects what mostly

A

Behaviour and language