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.
How can the visual fields be disturbed in parietal lobe lesion and why?
Because the superior optic radiations travel through the parietal lobe.
This can lead to contralateral inferior homonymous quadrantopia.
Functions of the temporal lobe.
Hearing
Olfaction
Memory
Emotion
Visual pathways.
Why can a lesion in the frontal lobe lead to hearing disturbances?
The primary auditory cortex resides in the superior part of the temporal lobe.
Why can a lesion in the frontal lobe lead to smell disturbances?
The primary olfactory cortex can be found in the medial part of the temporal lobe.
What can greatly enhance emotion and memory in the temporal lobe?
Smell as olfaction is closely associated with memory and emotion.
What type of visual field defect can a lesion in the temporal lobe lead to and why?
Inferior optic radiations run through temporal lobe.
This leads to contralateral superior homonymous quadrantopia.
Explain cerebral dominance.
Left hemisphere is dominant in 95% of people.
An example is most people are right handed.
