neuro diseases/syndromes Flashcards
where is the hippocampus
medial temporal lobe
types of declarative and non-declarative memory
declarative - semantic and episodic
non-declarative - skills, priming, basic associative learning, reflexes
what specific ion channel is involved in learning and memory
NR1 - key glutamate receptor
what is catatonia
motor immobility as evidenced by catalepsy or stupor
what do psychiatric illnesses affect
neurons, astrocytes and microglia leading to altered molecular pathways
epilepsy is characterized by…
recurrent unprovoked epileptic seizures
what causes seizures
paroxysmal excessive, synchronous, abnormal firing of populations of neurons in the brain - where it disrupts normal neuronal processing
why does someone get epilepsy
- genetic = inherited the predisposition
- structural/metabolic = something has happened to the brain as a result of injury
- unknown
what defines a partial (focal) seizure
arise in a limited number of cortical neurons within one hemisphere
what defines a generalized seizure
appear to arise simultaneously in both hemispheres
which cause of epilepsy usually responds well to medication and which type doesnt
responds well - genetic
doesnt respond well - structural
what causes the abnormal firing of neurons that causes seizures
a disturbance in the balance between inhibition and excitation of cortical neurons and neuronal networks (either increases or decreases in neuronal inhibition or excitation)
what can cause the disturbance in the excitatory-inhibitory balance causing seizures
- loss of inhibitory neurons
- gain of excitatory neurons
- aberrhant sprouting
- change in intrinsic neuronal cellular excitability –> change NT in the circuit
- alterations in synpatic transmission
- alterations in the extra-neuronal environment (glia)
what is the typical characteristic pathological pattern of medial temporal sclerosis
- cell loss in CA1, CA3 and dentate hilus regions
- mossy fibre sprouting
- glosis
why is medial temporal sclerosis so important
- commonest pathology in adults with partial epilepsy
- most refractory to medial drug therapy
- good prognosis with epilepsy surgery
what are the MRI signs of focal cortical dysplasia
- focal thickening of the cerebral cortex
- blurring of the grey/white interface
- gyral abnormalities
- may be associated with a region of increased T2 signal
what causes preiventricular nodular heterotopia
abnormal neuronal migration
what is the most common type of tumour to cause seizures
gliomas
what type of vascular lesions can cause seizures
cavernomas
arteriovenous malformations
what is focal encephalomalacia
focal lesion resulting from previous destructive insule
definition of cellular senescence
cells lose the ability to divide
what is organismal senscence
the ageing of whole organism
what is the difference between “successful” and “usual” ageing
successful - changes due solely to the ageing process, UNAFFECTED BY DISEASE, ENVIRONMENTAL OR LIFESTYLE FACTORS
usual - changes associated with THE COMBINED EFFECTS of the ageing process, disease and adverse environment and lifestyle factors
definition of frailty
diminished ability to carry out the important practical and social activities of daily living
why do we want to prevent someone becoming frail
they are unable to integrate responses in the face of stress and therefore are at risk for adverse health outcomes such as geriatric syndromes
what are the “biomarkers” of frailty
associated with a low grade chronic activation of the immune system
- cytokines (IL-6 and TNF-alpha)
- CRP
what is sarcopenia
ageing skeletal muscle due to altered CNS and PNS innervation, altered hormonal status, inflammatory effects and altered caloric, protein intake and disuse
when does the decline in skeletal muscle start to occur
begins in the 3rd decade
which muscle fibres are more affected by sarcopenia
type 2 fibres
proximal and distal muscles affected to the same amount
what are the clinical signs of frailty
slowness weakness weight loss low activity fatigue
What are the Fried’s criteria for frailty
- unintentional weight loss
- weakness
- exhaustion
- slow walking speed
- low physical activity
(pre frail = 1-2, frail = 3 or more)
definition of co-morbility
concurrent presence of 2 or more chronic diseases
definition of a disability
physical or mental impairment that limits 1 or more ADL
what are the geriatric syndromes
incontinence immobility impaired balance impaired cognition iatrogenic illness
What are the protein products leading to Alzeihmer’s disease
alpha-beta amyloid
Neurofibrillary tangles
Which chromosomes are involved in early onset AD
21, 14 and 1
sporadic mutation of which chromosome leads to sporadic AD
19
what are the 4 types of AD
Amnestic (temporal)
Visuospatial (R>L)
Aphasic (L>R)
Frontal
What is the precursor protein to amyloid plaques and how does it become amyloid plaques
APP
Cleaved by beta and gamma secretases which changes the conformation into beta sheets which is insoluble. This screws up neuronal signalling and ultimately leads to degredation
How does gamma secretase cleave APP
Introduces a water molecule into the transmembrane domain
Where are amyloid plaques deposited
On the membrane of extra and Intra synaptic sites
How do we currently diagnose AD
Measure the Amyloid peptide in the CSF and do a PET scan
What is the approximate time frame from normal to full blown AD
30 years
What is Creutzfeldt-Jakob disease
A rapidly progressing disease due to an infectious toxic protein in the brain
What causes mad cow disease
Abnormal Prion protein that is resistant to proteolytic degredation
Why are people not allowed to give blood if you have lived in Britain
Because mad cow disease goes into the blood and therefore can be passed on
Which protein is associated with Parkinson’s disease
Alpha-synuclein
