cerebral cortex Flashcards
cortical function: recognise the inter-hemispheric differences in cortical function, and recognise ways to assess cortical function, including lesions, functional imaging and brain stimulation
what 4 main lobes comprise the neocortex
occipital, parietal, temporal, frontal
3 features of primary cortices (symmetry, organisation, function)
predictable function, organised topographically, left-right symmetry
where is the autitory cortex
in superior temporal gyrus of temporal lobe
what causes callostomy (split brain patients)
where left and right hemispheres, which are specialised, are separated (born with no corpus callosum, or in epilepsy corpus callosum is cut to prevent spread)
what is the trade off in different methods used to measure brain function
invasiveness, spatial precision, temporal precision
2 examples of ligand binding non-invasive methods to measure brain function
SPECT, PET
microscopic to macroscopic brain structures
synapse -> dendrite -> neurone -> layer -> column -> map -> brain
when structurally imaging lesions, what is looked at
how they interrupt normal tractography, leading to complex symptoms
what is diffusion tensor imaging (MRI derivative), and what does it show
where movement of water molecules in brain is used to infer underlying structure of white matter; integrity of functional pathways (e.g. tumour, or more subtle differences in structure or function)
what happens in transcranial magnetic stimulation, and what does it test
induction of electrical current in cortex below coil, causing neurones to fire, and tests whether specific brain areas are responsible for a function (e.g. speech); therapeutics also (stimulation of damaged pathways)
what happens in transcranial direct current stimulation
changes local excitability of neurones, increasing or decreasing their firing rate (doesn’t directly induce neuronal firing)
how can transcranial direct current stimulation reduce motion sickness
by suppressing area of cortex associated with processing vestibular information
what happens in positron emission tomography (PET)
different radioactive tracers on ligands (e.g. dopamine) are traced as they emit positrons as they are absorbed in the brain
in positron emission tomography (PET), why is there a loss of signal in Parkinson’s patients
lower uptake of dopamine in posterolateral putamen
what happens in magnetoencephalography (MEG)
surface magnetic fields produced by natural brain electrical currents are recorded
