Brain Damage Effects on Memory [W4] Flashcards
Name two kinds of brain tumour
meningiomas, infiltrating
What are meningiomas
brain tumours that grow between the meninges, typically benign
What are infiltrating tumours [brain]?
Brain tumours that grow within the brain tissue, difficult to remove
Two types of strokes
haemorrhagic, ischemic
What is a haemorrhagic stroke? How common? How does it damage the brain?
haemorrhage (bleeding), may be caused by burst aneurism, very dangerous; about ~15% of strokes; damages the brain due to lack of oxygen downstream, also ‘leaking blood’ will pool and subsequent buildup of pressure damages the brain
What is an ischemic stroke? How common? How does it damage the brain?
stroke caused by a blood clot/blockage (blood supply occluded); most common ~85% of strokes; lack of oxygen to downstream parts of the brain
What is an aneurism?
bulge in a blood vessel caused by a weakness in the blood vessel wall [think: radiator hose incident in my Peugeot]
What is a stroke?
Loss of some blood supply to the brain, which means the “downstream” parts of the brain can’t get oxygen and glucose which are needed for brain function. This damages the brain tissue and leads to a loss of brain function; happens to varying degrees of severity
Why does a lack of oxygen to the brain cause damage?
Oxygen is required to convert glucose to energy. If that energy can’t be converted (due to lack of oxygen) then it can’t power the brain which starts to “shut down” where it can’t get oxygen.
The middle cerebral artery supplies blood to what key areas ?
Wernicke’s and Broca’s, etc.
What functions might be affected by a stroke preventing bloodflow to Wernicke’s area?
may have difficulty with speech processing and understanding language
What functions might be affected by a stroke preventing bloodflow to Broca’s area?
may have difficulty producing coherent speech
What determines the severity of a stroke?
location of the stroke, amount of brain tissue that is damaged
The basilar artery supplies blood to what key areas ?
brainstem (pons, medula, midbrain) and cerebellum
What is a tumour?
an abnormal mass of tissue cause by excessive cell replication/growth or cells not dying off when they should; can be benign (not cancer) or malignant (cancer)
What functions might be affected by a stroke in the anterior cerebral artery (ACA)?
affects motor cortex –> movement on other side of body
What functions might be affected by a stroke in the middle cerebral artery (MCA)?
speech, among many other functions
What functions might be affected by a stroke in the posterior cerebral artery (PCA)?
occipital cortex, vision on opposite (contralateral) hemifield
Def: hemifield [visual field]
one half of the visual field; usually divided vertically through the fovea into L and R field
What is the most common neurological disorder?
Alzheimer’s disease
What causes Alzheimer’s?
genetic and environmental causes leading to amyloid plaques and tau tangles (buildup of protein clumps)
What happens the the physical brain in someone with Alzheimers?
degeneration/loss of neurons and synapses, cortical atrophy
What is an amyloid plaque?
abnormally configured proteins that form in the spaces between neurons (outside the cells)
What are neurofibrillary tangles?
abnormally buildup of tau proteins inside the neuron; in healthy brains, tau binds to and stabilises microtubules. In Alzheimer’s brain, tau detached from microtubules and binds with other tau proteins.
What’s the difference between Alzheimer’s and Dementia?
Alzheimer’s is a specific brain disease; Dementia is a general term for symptoms like decline in memory, reasoning or other thinking skills
Where are plaques and tangles in Alzheimer’s patients?
Distributed everywhere but especially prominent in limbic areas
Why could brain damage be considered useful (neuroscience)?
Effects of brain damage can help in determining the role of the affected brain areas re: behaviour
Why could brain damage be considered useful (neuropsychology)?
Effects of brain damage can help in revealing how the mind is organised. ie., does damage to a specific area affect certain behaviours/functions and not others?
Famous patient who had bilateral removal of hippocampus and surrounding cortex to control epilepsy?
HM reported by Scoville and Milner (1957)
Explain patient HM (Scoville & Millner, 1957)
HM had severe seizures which left him unable to lead a normal life, due to a bike accident as a child. Desperate for a solution, he underwent an experimental procedure to control his epilepsy with lobotomist, William Scoville. Most of his medial temporal lobe (esp. hippocampus) was removed. Fixed seizures but left him with global anterograde amnesia (i.e., amnesia existed regardless of test type, material, or sensory modality). Forgot thing within 30 min. Severe long-term deficits (couldn’t convert to long term memory) for episodic memory (events) and semantic knowledge (new facts). Motor skills, perceptual and lexical priming, and classical conditioning unimpaired. Could learn new motor skills.
Why was HM (Scoville & Millner, 1957) significant?
One of, if not the first, memory study patient; showed that new memories are generally created in the medial temporal lobe but long term memories are not stored in the hippocampus.
def: retrograde amnesia
don’t remember anything that happened before brain damage
def: anterograde amnesia
can’t remember events that happened after brain damage
Who is Clive Wearing?
Example of severe case of anterograde amnesia
Hippocampus is important for what role re: memory?
Memory consolidation, short term memory
What structures are important in memory ?
perirhinal cortex (recognition); amygdala (emotional memories); basal ganglia (habit learning); hippocampus (memory consolidation and short term memory)
