18 - Cortical Asymmetry Flashcards
What is a suclus and gyrus?
Suclus is a groove in the brain and gyrus is a round ridge
What is the function of Broca’s area?
Speech production
Where is Broca’s area located?
Left frontal lobe,above the lateral suclus
Which Brodmann areas is Broca’s area?
44 and 45
Where is the primary motor cortex located?
Precentral gyrus (Brodmann area 4)
How does brodmann distinguish between different parts of the brain?
Differences in neuron type and density (50 different areas)
What is the association cortex?
Areas of the cortex where the function is obscure
Which hemisphere controls language?
Left hemisphere
What is the Insula?
A hidden region in the left cortex (inside the lateral suclus) which is active during speech production
Which side is the opercular cortex thicker on? What is it’s function?
Opercular cortex is thicker on the left side
It’s situated on the upper and lower lips of the lateral fissure
Function - language production
What is the function of Wernicke’s area?
Language perception
Where is Wernicke’s area located?
Proximal end of the superior temporal gyrus in the temporal lobe
What is the difference between expressive and receptive aphasia?
Expressive aphasia - Damage to Broca’s area - Can understand, repetitive, cannot form coherent sentences, sense behind words, disordered grammar, syntax and word order
Receptive aphasia - Damage to Wernicke’s area - Fluent speech, good syntax and no repetition however the content is meaningless
What is the name of the fibres which connect Broca and Wernicke’s areas?
Arcuate fasciculus
What is Conduction aphasia?
Damage to the arcuate fasciculus, patients show difficulty reading aloud, impaired ability to repeat back words and has word-finding difficulties
What are the 5 steps of the Wernicke-Geschwind model?
1 - Primary auditory cortex 2 - Speech perception - Wernick’s 3 - Connection - Arcuate fasciculus 4 - Speech production - Broca’s 5 - Motor cortex
What is the artery that supplies blood to Broca and Wernicke’s areas?
Middle Cerebral artery (From the Internal carotid artery)
What is global aphasia?
A stroke to the proximal part of the middle cerebral artery affecting both broca and wernicke’s areas
How do you test differences in function between the left and right hemispheres?
Before MRI they used the WADA test whereby anaesthetic was injected into the carotid artery on one side
What does the right hemisphere corresponding to Broca’s and Wernicke’s areas do?
Non-semantic speech recognition, recognising and producing intonation, rhythm and emphasis
What is aprosodia?
Lesion of the right hemisphere regions which correspond to broca’s area causing robotic, monotonous speech
Which area of the brain enables you to focus your attention and blocks out distracting inputs? Why is this clinically significant?
Left frontal lobes
Which area of the brain maintains broad overall vigilance?
Right frontal lobes
What brodmann areas are the posterior parietal cortices?
5 and 7
