cerebral cortex Flashcards
how thick is the cerebral cortex and how many neurons are within the cortex
2-4 mm thick (grey matter)
approximately 10-15 billion cells
what is the name of the primitive cortex
allocortex and has <6 layers
the neocortex
is the post-primative cortex and has 6 layers
what are the names of the 6 layers of the neocortex
the first two layers (molecular and external granular) are collectively called the supragranular cortex
the second two layers (external pyramidal and internal granular) are collectively called the granular layer
the third bi-layer (internal pyramidal and mutliform) is collectively called the infragranular layer
the cortical layers that have output to the association and other cortical area are
supragranular and layer III
input from the thalamus and other cortical areas occurs in which layer of the neocortex
layer IV (4)
output from the neocortex to the basal ganglia, brainstem, spinal cord occurs in which layer
layer V (5)
the final layer of the neocortex is called multiform and project cortical output to which location?
the thalamus
Brodman devised the cytoarchitectual map of the neocortex, Brodman area 4 and 3,2,1 respresent?
4 = M1 (primary motor cortex) 3,2,1 = primary sensory cortex
Primary cortical areas control
simple movement and sensation
Association cortices
perform higher order processing, deficits of which lead to complex phenomenon (alien hands)
The primary visual cortex
receives visual information
The superior and lateral visual association areas help process which aspects of vision
the superior (parieto-occiptal area) - analyses spatial infromation and movements (the where association cortex)
the lateral (occipito-temporal area) - analyses the colour and form of visual information (the what association cortex)
What are the three main types of white matter pathways?
- association fibres (one cortical region to another)
- commisural fibres (cross the corpus callosum - interhemispheric communication of cortices)
- projection fibres (project out of the brain)
What are the main cerebral functions of the following brain areas? frontal temporal occiptal parietal limbic
frontal - movement (RIO = restraint, initiative and order ie complex cognitive (personality) functions) parietal - sensation temporal - hearing and memory occiptial - sight/vision limbic - emotions, drive
What are some notable features of cortical disease?
- presentations are complex, they are not purely motor or purely sensory
- the deficits cause impaired interpretation of stimuli
- there is asymmetry with the hemispheres
in 90% of right handed people, and 70% of left handed people
the left hemisphere will dominate for language
the right hemisphere will dominate for attention and visual spatial processing
Hemispheric preference for language, and visual-spatial processing is not apparent till which age of life?
3-4 years of age
the prefrontal cortex has two main divisions (or areas)
dorsolateral (superior) and orbitomedial (inferior)
the dorsolateral is involved in executive functions
the orbitomedial is involved in impulse control, personality and mood
the premotor cortex has the greatest amount of post-natal brain development than any other brain region
In most people right and left handed people attention is commonly located in which hemisphere
the right
Parietal neglect syndrome
is where a person will fail to recognise the contralateral side of the body (visual field included)
Cortical syndromes
aphasia - difficulty speaking within intact motor function (dysarthria = abnormal motor function)
apraxia - cannot carry out a task with verbal command
cortical deafness - aware of sound, but not able to interpret sound
cortical blindness - unaware of visual loss
prospagnosia - unable to recognise faces
Gerstman’s
- agraphia
- acalculia
- R-L disorientation (differentiate R and L sides of body)
- finger agnosia (name of identify fingers)
caused by a non-dominant parietal lobe lesion
de’ja’vu, lip smacking, weakness and dizziness with a preceding metallic taste
are signs of a temporal epilepsy - could suspect a hippocampal lesion
