What is temporal resolution
temporal resolution refers to the discrete resolution of a measurement in respect to time, the lower the value the better the temporal resolution is
what does optogenetics refer to
turning neurons on and off
what are the 4 different causes of brain lesions
- vascular
- surgery
- trauma
- disease
How do vascular disorders affect the brain
- strokes occur when the blood flow is disrupted
- haemorrhages can also happen and leave sections of the brain destroyed
what are the 2 ways in which blood supply can affect us
- lack of blood
- hemorrhagic stroke
How does AD affect brain structure
white matter lesions (wiring of the brain) which impact the connections between neurons therefore affect behaviour
what area of the brain do traumatic brain injuries affect
orbifrontal frontal region
what happens when the blood flow is suddenly disrupted
cerebral vascular accidents or strokes
how do tumours affect neurological symptoms
damage to the neural tissue
or
by producing abnormal pressure on spared cortex and cutting off its blood supply
name examples of degenerative disorders
- parkinsons
- alzheimer
- huntington
- aids related dementia
in what way was Phineas Gage’s brain damaged
potential damage found (using MRI) to Bette link the sites of brain damage to changes in behaviour (personality and decision making)
what is prosopagnosia
- damage to temporal lobes
- one type can distinguish faces well but cannot recognise them
- the other type struggles to differentiate between faces
what is achromatopsia
- colour vision disturbed when lesions occur in the temporal lobe
- overlap brain regions with prosopagnosia but not in the same place
describe neglect (attention deficit)
- patients ignore the left half of visual space but can detect targets if presented alone
- this is interpreted as an attentional deficit
describe GY case study
- lesion to the primary visual cortex in the left hemisphere due to a road traffic accident
- one hemisphere bashed into the other and at the midline, it caused a lesion known and the contra coup lesion
what is homonymous hemianopia
- damage to the LVC
- you no longer see the right visual field
- this is an example of a right sided homonymous hemianopia
describe the term blindsight
- ability to discriminate between visual stimuli that were not consciously acknowledges as present by the patient
- patients cannot recognise objects but can distinguish between the objects they cannot recognise
what does TMS do?
overcome some issues of lesion studies
- the TMS coil is held by the experimenter against the participant’s head and the TMS pulse directly alters the neural activity in a spherical volume of approx 1cm^3
how does TMS disrupt visual processing
- the TMS pulse is applied on some trials either just before or just after the letter is presented
- the IV is the time between the TMS pulse and letter presentation
- visual perception is markedly disrupted when the pulse occurs 80-120ms after the letter due to disruption of neural activity in the visual cortex
describe experimental lesions
- animal models and surgical lesions
- they’re precise and done postmortem
- can’t always generalise to humans and go against plasticity and reorganisation
describe chemical lesions
- animal models and neurotoxins
- very precise but can’t be generalised to humans
what are congenital visual deficits
remapping of visual cortex as a result
congenital vs acquired
- acquiring a retinal lesion in adulthood does not lead to reamapping that is found the lesions are present sp age doesn’t matter
what is diffusion tensor imaging
captures the diffusion of water which is greater than axon - wiring of brain measured
what is single association
lesion affects brain area x so patient can do task a but not b - x and b are associated
