Higher Cortical Functions Flashcards
How is the cerebral cortex arranged?
Arranged in 6 layers containing containing cell bodies and dendrites (i.e. cortex is grey matter)
What are most outputs from the cortex?
They more mostly axons of pyramidal neurones (e.g. upper motor neurones in the primary motor cortex are pyramidal neurones)
Outputs can be projection fibres going down to the brainstem and cord (e.g. upper motor neurones)
Outputs can be commisural fibres going between hemispheres (e..g Corpus Callosum)
Outputs can be association fibres connecting nearby regions of cortex in the same hemisphere (e.g. accurate nucleus)
Where do most inputs to the cerebral cortex come from?
Thalamus and other cortical areas.
An important population of inputs arise from the reticular formation, maintaining cortical activation (consciousness).
What does the frontal lobe do?
Motor - primary motor cortex and associated areas. If damage = contralateral weakness.
Expression of speech (usually left hemisphere) - Broca’s area damage = expressive dysphagia
Behavioural regulation / judgement - Prefrontal cortex. Damage = impulsive, disinhibited behaviours e.g. sexual inappropriateness, aggression
Cognition - Prefrontal Cortex. Damage (right) = difficulty with complex problem solving and calculation
Eye movements - Frontal eye fields. Damage = problems with conjugate gaze and other eye movement disturbances.
Continence - Contain cortical areas for the maintenance of continuance (paracentral lobules). Damage = Urinary incontinance
What does the parietal lobe do?
Sensory - Contains primary sensory cortex and associated areas. Damage = contralateral anaesthesia affecting all modalities.
Comprehension of speech = Contains part of Wenicke’s area. Damage left parietal lobe = receptive dysphagia
Body image and awareness of external environment = involved with acknowledgement that things exist. Damage = neglect
Calculation and writing = work with frontal lobe. Damage to left parietal lobe can affect this.
Superior optic radiations go through here. Damage = contralateral inferior homonymous quadrantanopia.
What does the Temporal lobe do?
Hearing - Primary auditory cortex on superior surface near Wernicke’s area. Damage = hearing effects or auditory hallucinations.
Olfaction - Primary olfactory cortex on the infero-medial temporal lobe. Damage = Complex smell effects or olfactory hallucinations.
Memory - Hippocampus. Damage = amnesia (we but, we have two, one in each lobe).
Emotion - limbic system e.g. hippocampus and amygdala. Complex but related to pathogenesis of psychiatric disorders.
Inferior optic radiations through here. Damage = contralateral superior homonymous quadrantanopia.
What hemisphere is most dominant for language and mathematical / logic functions?
For 95% of people the let hemisphere is dominant for language and mathematical / logic functions.
What hemisphere is the most dominant for body image, visuospatial awareness, emotion and musical ability.
In 95% of people the left hemisphere is dominant for body image, visuospatial awareness, emotion and musical ability.
How do two hemispheres communicate?
Corpus Callosum
What can happen if the corpus Callosum gets damaged?
Destruction of the corpus Callosum can lead to interesting deficits such as alien hand syndrome and subtle effects on language and processing.
Where is Broca’s area? What is this near?
Inferno-Lateral frontal lobe near the mouth and pharynx areas of the primary motor cortex.
What does Broca’s area do?
Broca’s area is responsible for the production of speech.
What happens if you damage Broca’s area?
Causes staccato speech, where the patient still understands what is being said to them.
(Broca’s / expressive dysphagia.)
Where is Wernicke’s area? What is this near?
At the parieto-temporal junction near to the primary auditory cortex in the temporal lobe.
What is Wernicke’s area responsible for?
The comprehension of speech.
