Session 8 Higher Cortical Function Flashcards
(41 cards)
How is the cerebral cortex arranged (in terms of layers)?
Arranged as 6 layers containing cell bodies and dendrites (i.e. cortex is GREY matter)
What are most outputs from the cortex?
Most = The axons of pyramidal neurones
(E.g. UMN’s in the primary motor cortex are pyramidal neurones)
Outputs can also be:
- projection fibres going down to brainstem and cord (e.g. UMN’s)
- commissural fibres going between hemispheres (e.g. corpus callosum)
- association fibres connecting nearby regions of cortex in the same hemisphere (e.g. arcuate fasciculus)
Where do most of the inputs to the cerebral cortex come from?
The thalamus (plus other cortical areas)
NB: an important population of inputs arise from the reticular formation, maintaining cortical activation (consciousness)
What do interneurones connect?
What do interneurones give rise to?
Connect inputs and outputs in a complex way
Give rise to behaviour, emotion, memory etc
FRONTAL LOBE
Motor area?
Frontal lobe damage causes?
Motor area = primary motor cortex
Frontal lobe damage can result in:
CONTRALATERAL WEAKNESS
FRONTAL LOBE
Expression of speech - which area?
Damage results in?
Area = Broca’s area
Damage to left frontal lobe can result in:
EXPRESSIVE DYSPHASIA (= impaired language production)
FRONTAL LOBE
Behavioural regulation / judgement
Area?
Damage?
Area = prefrontal cortex
Damage to frontal lobes can lead to :
Impulsive, disinhibited behaviours
E.g. sexual inappropriateness, aggression
FRONTAL LOBE
Cognition
Area?
Damage?
Area = prefrontal cortex
Frontal lobe damage (particularly the right!) can cause difficulty with tasks such as complex problem solving, including calculation
FRONTAL LOBE
Eye movements
Area?
Damage?
Frontal lobe contains the frontal eye fields
Damage can cause:
- problems with conjugate gaze and other eye movement disturbances
NB: diplopia without other cortical features would suggest brainstem/cranial nerve problem
FRONTAL LOBE
Continence
Area?
Damage?
Area = frontal lob contains the cortical areas responsible for maintenance of continence e.g. paracentral lobules
Damage can cause:
Urinary incontinence
PARIETAL LOBE
Sensory
Area?
Damage?
Area = primary sensory cortex and associated areas
Damage might result in:
Contralateral anaesthesia affecting ALL modalities (modalities converge at the cortex)
PARIETAL LOBE
Comprehension of speech
Area?
Damage?
Area = parietal lobe contains part of Wernicke’s area
Damage to left parietal lobe can cause:
A receptive dysphasia (difficulty in comprehension)
PARIETAL LOBE
Body image and awareness of external environment
Area?
Damage?
Parietal lobe seems to be involved with acknowledgement that things (including the body) exist
Damage to the right parietal lobe can lead to neglect
PARIETAL LOBE
Calculation and writing
What does it work with?
Damage?
Works with the frontal lobe to perform these tasks
Damage to the left parietal love can affect calculation ability (but maybe also frontal lobe)
What optic radiation projects through the parietal lobe? What could damage here cause?
Superior optic radiation
Damage here can cause:
A contralateral inferior homonymous quadrantanopia
TEMPORAL LOBE
Hearing
Area?
Damage?
Primary auditory cortex sits on superior surface of temporal lobe (near to Wernicke’s area)
Damage can lead to a number of complex effects on hearing (all you need to know)
Auditory hallucinations may be a feature of temporal lobe lesions
TEMPORAL LOBE
Olfaction
Area?
Damage?
Primary olfactory cortex sits on the infero-medial aspect of the temporal lobe
Damage can lead to a number of complex effects on smell (all you need to know)
Olfactory hallucinations may be a feature of temporal lobe lesions
TEMPORAL LOBE
Memory
Area?
Damage?
The hippocampus is a crucial structure for consolidating declarative memories
Damage may lead to amnesia
Some pathologies such as temporal lobe epilepsy can trigger memories leading to a feeling of deja vu
TEMPORAL LOBE
Emotion
Area
Damage
Temporal lobes contain a number of limbic system structures such as the hippocampus and amygdala
Effects of lesions are complex but may be related to pathogens is of some psychiatric disorders
What optic radiation projects through the temporal lobe? What would damage here cause?
inferior optic radiation
Damage here can cause:
A contralateral superior homonymous quadrantanopia
In 95% of people, what is the left hemisphere dominant for?
Language and mathematical/logical functions
In 95% of people, what is the right hemisphere dominant for?
Body image, visuospatial awareness, emotion and musical ability
Where is Broca’s area?
What is Broca’s area responsible for?
What can damage here cause?
Area = in the infero-lateral frontal lobe and sits near to mouth/pharynx area of primary motor cortex
Responsible for = production of speech
Damage can cause = staccato speech - the patient understands what is being said to them but patient speaks in fragments of sentences that are punctuated by pauses (expressive dysphasia)
Where is Wernicke’s area?
What is it responsible for?
Damage causes?
Area = at the parieto-temporal junction
Sits near the primary auditory cortex in the temporal lobe
Responsible for = comprehension of speech
Damage can cause = fluent, nonsensical speech where the patient DOES NOT appear to understand what is being said to them (receptive dysphasia)
