W10: Neurolinguistics, neuroimaging, language problems Flashcards
What is phrenology?
Looking at the shape of the head as though indicative of mental processes or character traits (Gall)
What does phrenology say about language?
Would suggest that language is localized to a particular brain region that would protrude when using language
Is the concept of phrenology correct?
No its not right, but the underlying idea of localization is still valid
Things like vanity, friendship and wisdom is not localised as gall proposed.
Are there any sex differences in language lateralization?
Males are more lateralised when it comes to language, being represented in just one hemisphere
Female brains are less lateralised with language - more spread out across the hemispheres
Explain language critical periods
The ability to acquire language declines with age
- language input must occur during critical period for development to proceed normally
What is evidence towards language critical periods?
Lateralisation of language
Second language acquisition (children learn better - adults struggle)
Children deprived of early language (e.g. genie didn’t learn syntax but hard to disentangle from other problems eg. neglect)
What is the subtraction method in brain imaging?
Have the participant carry out one task, then do a variant of that task
Subtract one image from another - you can then identify differences and attribute areas towards function
What are some critiques of the subtraction method?
Areas of the brain can be active without being critical
People can be dimly thinking about something else at the same time - you can’t assume they are focussing on just the one task
Neuroimaging involves what trade-off?
Temporal (what) vs. spatial (where) accuracy
Explain event-related potentials (ERP)
Place electrodes against the scalp to record the electrical activity of the brain
Present a stimulus - measure voltage changes
Is there a trade-off in ERP?
Good temporal resolution - you can tell when
But you cant tell where - poor spatial resolution
Explain ERP peaks
Labelled in terms of polarity (positive/negative) and latency (ms since stimulus)
Interestingly, a negative peak is above the line and a positive peak is below the line
Explain magnetoencephalography (MEG)
Recent method
Measures magnetic activity in the brain
Good temporal and spatial resolution (can tell when and where things happen)
Not done unless it really has to be
Why isn’t MEG used very often?
Very difficult and expensive to conduct
Need superconducting devices, extreme cooling and magnetic shielding (need shielding from magnetic activity because want to explore the tiny emissions given off by the brain)
Explain computerised axial tomography (CAT)
X-ray images are taken from all angles around the head and are integrated to form a whole picture
What are the pros to using CAT scans?
They are non-invasive, are well tolerated and are not as expensive as others
What is the temporal/spatial trade-off in a CAT scan?
Alright both temporally and spatially but not great either way
