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
What are the Causes of Wernicke’s Aphasia
The same as Broca’s
- Stroke (2 types - haemorrhage, blood clot/ supply)
- Head injury (internal)
- Tumour (of brocas, or in between meninges)
- Viral infection
What are Wernicke’s Aphasia Symptoms
PROBLEMS CONVERTING THOUGHTS TO WORDS
- They have lots of vocabulary and can talk fluently
- But the narrative of their speech is jumbled, and hard to follow, it has lots of words, but it is not coherent
- NEOLIGISM’S - can also see neoligsm’s - words that they have made up/ coined themselves
NOT a lack of vocabulary
DIFFICULTY converting what they want to say into conventional communication of words
Outline University Of Wisconsins - Department of Physiology videos about Wernickes
Again, the patient shows frustrations
- as they have vocab, and some phrases come out okay, but most of what is said is muddled or confusing
- Frustration can also be because the other person is not understanding them and they dont know why (if severe)
- Looks mad or insane, but is likely very intelligent, just on face value looks mad
Can those with Aphasia’s write?
DEPENDS
It depends on severity and location of the Aphasia
- they might not be able to write stuff
Do they realise they are making sense?
DEPENDS
- on severity and location again
- They might not realise they are not making sense, even if written or spoken, they can see others aren’t understand but dont know why or that it is their fault
Is it the same as a stammer?
NO
- Stammer is an entirely motor related issue
- They have all the words they want to say, and know what they want to say
- Can convert thoughts into instructions for mechanisms - but mechanical problems prevent speech and sounds in general being produced
How can you recover from Stroke? - Sarah Scott
Sarah Scott documented the process of her recovering from a stroke that left her with Broca’s Aphasia
- over a period of a few years she managed to recover her production abilities - but this was only due to INTENSIVE REHABILITATION - it wont cure itself
- As the brain is specialised, you can’t just create entirely new pathways
- but it is plastic - meaning it can improve current pathways (but cant make new ones) other areas of the brain nearby can take over some of the function and recover abilities
THIS CAN ONLY HAPPEN THROUGH INTENSIVE, LONG TERM REHABILITATION
The sooner you get help and start recovery, the better
Outline the Wernicke-Geschwind model (late 60s/ early 70s) COGNITIVE MODEL (Not phsyical)
COGNITIVE MODEL
After Wernicke died in 1905, Norman Geschwind made this model.
This model argues that these two areas of the brain, Broca’s and Wernickes, although being in different regions of the brain, and having different functions, and different aphasias
- THIS MODEL ARGUES THE TWO AREAS ARE COGNITIVELY LINKED.
Process:
- Sensory information - from the world, visual/ auditory etc
- Wernickes area - processes this information as meaning something (i.e. a word)
- if this area is intact, and words are semantically understood (know what it is), it then goes to Broca’s area to be converted into motor information - Broca’s Area - creates instructions to produce that word, converts it into motor information
- If damaged, it wont convert this information into instructions for motor area, or will send faulty instructions
- If in tact: sends information to motor areas - Motor area - produces the actual words
- if motor area is damaged - wont produce words/ sounds correctly
- cant follow instructions properly
What are limitations of the Wernicke-Geschwind model?
X - far too simple - much more going on in recognising a word and producing it
X - localisation of function is far too rigid - ignores other brain areas are involved
√ - a good attempt, but there is much more going on in recognising a word and producing it
- ignores other brain areas
Outline the Physical vs cognitive debate
How much can a cognitive psychologist actually teach us about understanding something physical like aphasia
- how much should we stick to physical accounts
There are pro’s and cons to both
What are the Pro’s of a physiological account?
√ - It’s real, you can see it, it is indisputable damage
√ - Can be clinically specific - can be very specific about the damage to an area, what has caused it and what are the symptoms
√ - We are fundamentally physical beings - can’t get anything more physical than tissue - can’t see thoughts
These are limitations of the cognitive account
What are the Pro’s of a cognitive account
Argues we should include mental processes
√ - There is more to our brain than physical stuff - thoughts and cognitions are clearly very important - so we need to look at that, and this approach does
√ - The other model ignores logical connections between understanding and producing a word, this model doesnt
TRUMP CARD:
√ - can apply this stuff to machines/ Robots - if we can plot the process of going from wernickes - Broca’s, surely we can apply this instructions to computers/ robots to teach them how to follow this process. Get them to enact the instructions between Wernickes (understanding a word) and Broca’s (producing a word)
