Cerebral Cortex Flashcards
what does the cerebral cortex contains ? and how thick is it?
it covers the entrie surface of the brain. it is about 2-3mm thick.
Together with the deep nuclei, it contains grey matter.
organised into lobes and has folds called gyri
Describe the microscopic organsiation of the cerebral cortex?
it is organised into layers and columns
draw out and label the layers of the cerebral cortex
Draw out and label the columns of the cerebral cortex
Describe how Bordmann classifed the 52 different regions of the brain
Cytoarchitecture.
This is bascially cell size, spacing or packing density and layers.
these cytoarchitecture relates to different functions
what are the functions of the frontal lobe?
what are the functions of the parietal lobe?
- sensation - pain and touch
- sensory aspect of language
- spatial orientation and self perception
What is the function of the occipital lobe?
Processing visual information
what are the functions of the temporal lobe?
what does the limbic lobe entail and what does it do?
it contains the :
- cingulate gyrus
- Amygdala
- Hippocampus
- Mammillary body
it’s functions are: learning, memroy, emotion, motivation and reward
what is the insular cortex and what does it do
it lies deep top the lateral fissure.
it is concerend with:
- interoception
- visual-vestibular intergation
- auditory processes
- visceral sensations
- autonomic control
what are the arrows poitning out and desciribe the features of the cells.
Grey matter- umyelinated cell bodies and glial cells. around 85 billions
Whtie matter- myelinated axons arranged in tracts
What are the 3 different types of white matter tracts and what do they each do?
they connect cortical areas of the brain.
What are the 2 different types of association fibres?
Short fibres (u-fibres)- connects adjacent cortical regions.
green in image.
Long fibres - other colours in image
The image below show the short and long association fibres.
label the long fibres and give function.
- Pink - the SUPERIOR LONGITUDOINAL FASCICULUS: it connects frontal lobe to occipital lobe.
- purple- ARCUATE FASCICULUS: connects frontal lobe with temporal lobe (broca’s area to wernicke)
- blue- INFERIOR LONGITUDINAL fasciculus- connects temporal lobe to occipital lobe
- orange- UNCINATE fasciculus- connects anterior frontal lobe to temporal lobe.
what are the 2 commisural fibres of the brain
what are the types of projection fibres?
Afferent- towards cortex
Efferent- away from cortex
Deeper to the cortex what do the projection fibres radiate as? and hwere do they converge?
Thye radiate as the corona radiata
They converge through the internal capsule between thalamus and basal ganglia
What are the differences between primary and association cortices?
label the respective areas in the frontal lobe
What are the respective functions of the priamry motor cortex, premotor area and supplementary area of the frontal lobe?
what are the functions of the primary somatosensory cortex and somatosensory association
Primary- it processes somatic sensations in the body arising from receptors
Assocation- interprets significance of sensory information ie. recognising information/thing placed in hands when eye is closed. it is also responsible for self awareness and personal space awareness.
What are the functions of the primary visual cortex and association cortex
Primary- processes visual information.
Association- interprets and gives meaning to visual input
What are the functions of the primary auditory cortex and assocation cortex?
What are the functions of the prefrontal cortex?
- attention
- planning
- adjusting social behaviour
- personality erxpression
- decision making
What are the respective functions of the Broca’s and Wernicke’s area?
Broca- since it’s close to the motor area. it is responsible for PRODUCTION of speech
Wernicke’s area- understanding language, whether spoken or written
What are the implications of frontal lobe lesions ?
Changes in personality
Inappropriate behaviour
Whar are the implications of Parietal lobe lesions
Contralateral neglect of self and other world class (extrapersonal space). ie. if lesion is ont he right, he’d lack awareness the left side of the body and left side of the world
What are the implications of lateral and medial lesiosn to temporal lobe
Lateral- agnosia- inabiltiiy to recognise things although you can still see it.
Medial- anteroregrade amnesia; can’t form NEW memories.
What are the implications to lesions in Broca’s and Wernickes area?
Broca- Expressive aphasia
Wernicke- Receptive aphasia
What are the implications of lesions to primary visual cortex and visual association cortex
Primary- blindness in corresponding visual field
Association- deficits in interpretation of visual information. e.g facial blindness (can’t learn new faces) or prosopagnosia (can’t recognsise familiar faces)
In assesing cortical function, what are the 2 imaging methods and contrast them
PET- injects redioactive glucose (risky) and then tell them to do tasks and watch the brain area that lights up. it checks blood flow to particular brain region.
fMRI- action is taking and then it measures blood oxygen in brain region. ie. proportion of oxy: deoxy blood.
THEY BOTH HAVE DIFFERENT SPATIAL (detailed info you can see) AND TEMPORAL RESOLUTION (lowest amount of time)
What are the types of encephalography used in assessing cortical function
EEG- MEASURES ELECTRIC signals produced by brain
MEG- measures magnetic signals produced by the brain.
it produces event related potentials
Why is a flipped chessboard used as a stimulus to visually evoke potentials and give the signifcance oif the numbers and letters on the graph
Flipped chessboard is used as it produces 100s of stimulus for the brain so that the potential can be picked up.
P50 - postive but it shows NEGATIVE deflection 50ms after stimulus
One of the ways of assesing cortical function is through brain stimulation. TMS can be used to stimulate the brain. Explain what this entails and give any clinical relevance for it
TMS uses electromagnetic induction to induce current in brain to bring about a function in the body as it stimulates neurons. Hence can be used ton assess fucntional intergroty of neural circuits.
MAY be used clinically for:
- epilpesy
- depression
- tinnitus
- migraine
what is tDCS? give relevant details
Transcranial direct current stimulation
it uses low direct current over scalp to stimulate or inhibit neuronal firing rates.
can be used to inhibit chronic pain/ major depressive disorders or epilepsy
what is DTI and what does it entail
Diffusor tensor imaging - based on diffusion of water molecules and hence can check the activity of the neuronal tracts
There is also DTI with tactography
Explain how somatosensory evoked potenitals work in encephalography
Stimulus put in hand and then electrodes placed at diffferent points in body from spinal cord up until crown of head.
Potentials are measured sequentially along the somatosensory pathways
Draw out the electrodes needed for encephalography
