LECTURE 22 - neurodegeneration Flashcards
What is neurodegeneration?
- large group of neurological disorders with no apparent cause
- very few are genetically determined biochemical disorders
Why do neuronal changes occur in response to?
- damage
- reaction to damage
can be - non-specific: cell death
- specific: disease specific pathology
What do consequences of neurodegeneration depend on?
Depends on the SITE not the type of degeneration
What are the disorder of movement and system degenerations?
Akinetic/rigid movement disorders:
- Parkinsonism
- Stiff man syndrome
Hyperkinetic movement disorders:
- Chorea
- Myoclonus
- Dystonia
- Tics
Ataxic movement disorders:
- Spinocerebellar degenerations
Motor neurone disorders
- Motor neurone disease
- Spinal muscular atrophy and related disease
What is dementia?
- an acquired ‘global’ impairment of intellect, memory and personality without impairment of consciousness
learning = acquisition of new info or knowledge memory = retention of learned info
What information processing pathways are associated with learning and memory?
cortical association areas –> parahippocampal region –> hippocampus –> thalamus
Describe the variation of synaptic plasticity
- brain regions responsible for integrative functions have highly plastic synapses e.g. limbic system (hipp. parahipp.)
- brain regions responsible for descriptive and executive functions have rigid synapses (e.g. primary sensory motor areas)
- the higher the plasticity, the higher the age related neuronal loss
What is Alzheimer’s disease?
- a progressive dementia of long duration
- increases in prevalence with age
- irreversible and eventually leads to early death
- ~60% of dementia cases
What cognitive deficits arise from AD?
- memory (LTM & STM)
- decision making
- judgement, insight, future planning
- language
- praxis and visuo-spatial processing
However the procedural memory, aspects of language and motor skills are spared
What happens to the brain areas of AD patients?
- medial temporal lobe structure shrinks
- hippocampus shrunken
- hippocampus is the first to be affected and is the most affected
- severe brain atrophy (however not to the back of the brain)
What happens to blood flow in the brain in AD?
- highly reduced blood flow
- lack of flow in parietal temporal lobe (receives direct input from hippocampus)
What is the pathology of AD?
- senile plaques accumulate
- intracellular neurofibrillary tangles (NFT) accumulate also
- NFT affect hippocampus first, spread to lateral temporal love
- leave primary sensory and motor areas unaffected
What can affect AD?
- age (biggest influencer)
- head injury
- low education
- menopause
- smoking
- high BP
What is multi-infarct dementia?
- blood vessels can be obstructed causing that part of the brain to die
- also known as cerebrovascular dementia
- little holes = infarcts that affect neuronal networks severely
What is PD with dementia?
Lewy body dementia
~30% Parkinson patients develop dementia
- dementia can arise first
