cortical organisation and function Flashcards
what does each lobe do?
frontal- controls motor function, language and memory
parietal- sensation and spatial orientation
temporal-auditory, emotion and memory
occipital-visual
limbic lobe-learning, motivation and reward
insular cortex- ANS
what is the difference between grey and white matter?
grey matter are neuronal cell bodies whereas the white matter are the axons
what are the different types of white matter tracts and what are each of their functions?
association fibres- connect lobes within the same hemisphere
commissural fibres- connect homologous structures in the left and right hemisphere
projection fibres- connect the brain lobes to lower parts of the CNS eg
the spinal cord
what are the types of commissural fibres found?
corpus callosum
anterior commissural fibre
what are the types of association fibres found?
superior longitudinal- frontal and occipital
inferior longitudinal- temporal and occipital
arcuate fasciculus- frontal and temporal
uncinate fasciculus- frontal and temporal
what are the types of projection fibres found?
corona radiata- deep to the cortex
what are the frontal lobe areas and what do they do?
primary motor cortex- control fine movement
supplementary area- plans internally queued movements eg speech
premotor area- plans externally queued movements eg seeing something and wanting to pick it up
what are the parietal lobe areas and what do they do?
primary somatosensory- processes somatic sensations coming from receptors on body eg vibration
somatosensory association- interprets these somatic sensations
what are the temporal lobe areas and what do they do?
primary auditory- processes auditory stimuli
auditory association- interprets sound
what are the occipital areas and what do they do?
primary visual- processes visual stimuli
visual association- interprets visual stimuli
what do the prefrontal cortex, wernickes and broccas area do?
prefrontal cortex- controls attention, behaviour, social awareness, planning
wernicke’s- understand speech
broccas- produces speech
what do lesions in each of the lobes and areas look like?
frontal lobe- change in behaviour, can’t perform fine precise movements
parietal lobe- contralateral somatosensory defects and lack of personal awareness (also contralateral)
temporal lobe- anterograde amnesia (inability to form new memories) and agnosia
occipital lobe- blindess or prosopagnosia (inability to recognise faces)
brocca- expressive aphasia
wernicke- receptive aphasia
how do you assess cortical function?
EEG- electroencephelography. measures electrical signal produced in the brain
what is multiple sclerosis and how does it present both clinically and on examination?
demylenation of neuronal axons in the CNS
presentation: blurred vision, fatigue, parasthesia, difficulty walking, muscle stiffness, spasms
examination: when checking conduction time MS will present with a delayed total motor conduction time but a normal peripheral conduction time showing the problems is in the CNS
What are M-waves, F-waves and H-reflexes?
When do these happen?
Happen when there is a stimulation to a peripheral nerve, this activates sensory or motor axons to make a muscle move or twitch
M-wave: motor axon response and fast (referring only to Motor fibre)
F-wave: large stimulus can cause motor axon to travel antidromically (first goes towards spinal cord instead of muscle) NOT REFLEX
H-reflex: sensory axons (subject feels stimulus) and action potential travels into spinal cord- causes reflex (both sensory and motor axon- the whole journey)
