Lecture 6 - Language Flashcards
Outline what is meant by the term ‘lateralisation’
Lateralisation refers to how a function occurs in one side more than the other
- for instance: Language is a rather lateralised function, as it predominantly takes place on the left hemisphere of the brain
What are the 3 branches of evidence for lateralisation?
- Brain Scans
- Dissection
- Reduced brain flow
Where are Broca’s and Wernickes in the brain? Like where are they?
- Broca’s is in the inferior frontal lobe, near the border with the temporal
- Wernicke’s is on the border between the temporal lobe and the parietal lobe - at the junction that those meet
- above the ear basically
(DIAGRAM)
Outline dissection as evidence for brain lateralisation
- the other two are reduced blood flow and brain scans
Dissection
- This method was more commonly used in the 1800s when there wasn’t stuff like brain scans
- A common method was to treat a patient throughout their lifes, who presented certain symptoms. You monitored the progression and evolution of these symptoms throughout their death
- Then after you died, you would dissect their brain, and attempt to correlate any symptoms from when they were alive to observed damage on their brain
- You just have to infer cause and effect, cannot be certain, just hope that the organic damage was actually the cause of the symptoms.
Indicates that certain areas are more responsible for functioning than others - as damage their reults in loss of function
Outline reduced blood flow as evidence for lateralisation
- the other two are dissection and brain scans
Instead of brain scans or dissection, you can use this method
- you temporally cut off blood supply to a certain area of the brain, for instance the COMMON CAROTID ARTERY which supplies blood and oxygen to the head, brain and neck - To see what happens to functioning
- For instance if you do this to Broca’s area, i.e. cut off the blood supply, you will induce symptoms similar to if a patient has a lesion in that area
Indicates again lateralisation, as shows an area is important for a function
Outline who Paul Broca was and what he provided
Paul Broca (1824-1880)
He was a neurologist working in paris, who had a number of famous patients, from which he provided the first evidence, neuroanatomical evidence, toward the concept of brain lateralisation
He found that most of his patients could be treated, but some didn’t respond well to the rehabilitative methods at the time.
Outline Broca’s 2 Famous patietns
- Mr Leborgne = Mr Tan
- could only say the word ‘Tan’
- Post-mortem, Broca’s dissected his brain and found a massive hole in the area that became known as Broca’s area - a large lesion in the inferior frontal lobe - Mr Lelong
- could only say a few words, like Oui, Non, Toujours, Lelo
•Patients could understand language, and what was said to them, and made use of their limited vocab as best they could - but couldn’t express themselves
•No amount of rehabiliation could teach them new words
- nothing like reward, hypnosis etc would work
- just couldnt expand their vocab
Outline the work of Dronkers et al (2007)
Dronkers et al (2007)
Mr Leborgne’s brain was preserved in formaldahyde for 100 years or so
- Dronkers et al (2007) decided to work on it
Although they could analyse his brain again from external
- they scanned his brain using modern imagery techniques - this enabled them to look at his brain internally as well - something Broca was unable to do
They found: that damage was also internal and extensive, however, they didnt know if this would have had any impact on language abilities
- perhaps it implicates further then Broca’s or perhaps not
What are the 4 main causes of Broca’s Aphasia
- Stroke (most likely)
- Haemorrhage or blood supply - Head injury - but has to be internal
- can’t just be external - e.g. concussion or knock to the head
- has to cause internal damage - like a bullet or a spike through the head - Brain tumour
EITHER:
- Tumour of BROCA’S ITSELF - becomes malignant, neurons stop functioning - they die and become a tumour
OR
- A tumour in between Broca’s area and the meninges - crushing Broca’s area - Viral infection
- Viral infection of the brain can damage broca’s or impeded its functioning
What are the 2 causes of stroke?
- Haemorrhage (bleed) caused by an aneurysm (swollen artery wall causes blood pocket) bursting
- Blood clot in the artery cutting off blood supply to the brain
- So either: Bleed near brocas or lack of blood supply to the brocas
What is main few symptoms of Broca’s Aphasia
PRODUCTION PROBLEMS
- Very Limited Vocabulary
- Incomplete speech
It is often quicker for these patients to communicate with their hands, so they often type out stuff
What is one way you can kind of tests for Broca’s Aphasia?
You can tests for Broca’s Aphasia
- for instance by showing them a complicated scenario and getting them to describe it
- e.g. a man in a cowboy hat washing up, they might say:
- “Man….hat….hand water and…….dish….cups….soap”
Give an example of an extract from someone with Broca’s
For instance, if talking about a dental appointment:
“Yes….Monday….Dad and Dick….. Wednesday nine o’clock….10 o’clock…doctors….and…..teeth”
Outline the Example from the Wisconsin University Department of Physiology
In a video from the University of Wisconsin, department of Physiology, they produced a number of videos in the 1960s, documenting cases of Broca’s Aphasia
The patients in these videos show frustration. This is because they understand the questions they are asked, and they know what they want to say and which words to use, but they just cant say it - its very frustrating
- they can read, and hear it but cant produce it
Outline Carl Wernicke, who was he
Carl Wernicke (1848-1905) He was a german Neurologist working around the same time - similarly: he also had a range of patients who had language problems - but this time, when he did a post-mortem examination - their damage was not in inferior frontal, but actually at the junction of the temporal and the parietal
