Session 8: Higher Cortical Function Flashcards
How many layers of the cortex?
6
Where are most inputs from that are going to the cortex?
Thalamus
Cortical areas (meaning the cortex loops back on itself)
Where are most outputs from (going from the cortex)?
From pyramidal cells
What type of fibres can pyramidal cells be?
Projection
Commissural
Association
The output is going to widespread areas
Functions of the frontal lobes.
Motor
Expression of speech
Behavioural regulation and judgement
Cognition
Eye movements
Continence
Why can a lesion in the frontal lobe lead to motor disturbances?
Because the primary motor cortex can be found in the pre-central gyrus of the frontal lobe.
Why can a lesion in the frontal lobe lead to disturbances of expression of speech?
Because Broca’s area is found in the frontal lobe.
Brocas area is closely associated with the primary motor cortex and especially the tongue and larynx.
Give examples of some behavioural disturbances and judgement might happen in a frontal lobe lesion.
Impulsive
Disinhibited behaviours
Sexual inappropriateness
Aggression
Give examples of cognition difficulties with frontal lobe lesions.
Difficulties with complex problem solving and calculations.
Why can a lesion in the frontal lobe lead to continence issues?
Because the UMV supply urethral and rectal sphincters.
If a patient has difficulty in expressing themselves, which half of the frontal lobe is most likely to be damaged?
Broca’s area is most commonly found in the left frontal lobe.
Functions of the parietal lobes.
Sensory
Comprehension
Body image
Awareness of external environment
Calculation and writing
Visual pathways
Why can a lesion in the parietal lobe lead to sensory disturbances?
Because the post-central gyri where the primary sensory cortex resides can be found in the parietal lobe.
Why can a lesion in the frontal lobe lead to speech comprehension issues?
Because Wernicke’s area can be found in the parietal lobe which is closely associated to the primary auditory cortex in the temporal lobe.
A lesion here will give difficulties understanding speech.
In Wernicke’s aphasia, which parietal hemisphere is more likely to be affected?
The left.
Wernicke’s area is most commonly found in the left hemisphere.
Explain the body image disturbances that can occur in a parietal lobe lesion.
It leads to neglect.
This means that you might see left half of space but don’t acknowledge its existence.
An example is that a man might only shave half his face.
If a patient has neglect of the left side of their space.
Which hemisphere of the parietal lobe is more likely to be affected?
The right one.
This is because the left parietal lobe only deals with space on the right half.
The right parietal lobe deals with space on both halves.
This means that a lesion in right half would lead to only right half still being consciously aware.
Explain the pathway for repeating a heard word.
Sound is sent from the ear to the primary auditory cortex.
The PAC then communicates with Wernicke’s area.
Wernicke’s area will then communicate with Broca’s area via arcuate fasciculus.
Broca’s area then sends stimulus to primary motor cortex (mouth/pharynx area) leading to production of speech.
Explain the pathway for speaking a written word.
Visual stimuli from primary visual cortex goes to WA.
WA -> BA (arcuate fasciculus)
BA -> PMC
Explain the pathway for speaking a thought.
Thinking comes from all areas of the cortex -> WA.
WA -> BA
BA -> PMC
Explain the molecular and cellular mechanisms of memory.
Long term potentiation
Strengthens synaptic connections
