neuroimaging and disease

Question 1

what does a CT scan show?

Answer 1

high signal (bright) = calcium, blood, contrast agent

low signal (dark) = water e.g. edema or cell swelling

Question 2

what is EEG and how does it work?

Answer 2

EEG = electroencephalogram

records cortical electrical energy from the scalp
– excitatory post-synaptic potential generates an extracellular dipole at the apical dendrites of pyramidal cells
– generates electrical field in pyramidal cells which can be detected on scalp

has high temporal resolution but poor spatial resolution

Question 3

what is hippocampal sclerosis?

Answer 3

hippocampal sclerosis is neuronal loss + gliosis in the hippocampus:
– neuronal loss in CA1, CA4 and dentate gyrus
– gliosis
– granule cell dispersion

can be a cause of epilepsy