Language Flashcards
language: the highlights
languages are all fantastically complex, language knowledge = implicit knowledge (there are rules but we cant define them all), uniquely human (we can do a lot more with language than other species), universal among humans
aphasia
partial or complete loss of language abilities following brain damage, often without the loss of other cognitive abilities or the function of muscles (e.g. mouth, tongue, throat, lungs) used in speech. aphasia patients provided earliest evidence of language ares in the brain
drawbacks of studying aphasics
we want temporally and spatially specific data about which brain areas seem to do what and when. Aphasics are small limited population while normal people are numerous. The injuries that lead to aphasia are not always contained to the area of interest. Loss of function doesn’t tell you whether the area is directly or indirectly implicated.
the wada procedure
injected anesthetic into left carotid artery to affect left side of brain. subjects couldn’t speak until it wore off
lateralization
when subjects did linguistic tasks, more activity on left side of brain shown in fMRI. BUT, language is not completely lateralized. While it remains true that the left hemisphere processes most aspects of language, some aspects of language are processed in the right hemisphere.
role of right hemisphere in language
more active during processing of figurative language (like metaphors and the plausibility of a sentence) and responds more to sentential prosody (pitch, duration, and volume of speech)
near-infrared optical topography (OT)
optical fiber bundles placed on head. measure changes in blood flow (hemodynamic responses) and, thus, in brain activation. pretty good temporal resolution and spacial specificity
roles of right vs. left summary
left: more activation for most language tasks. syntax (grammar), phonology (speech sounds), words, lexical pitch. right: more activation for extralinguistic language tasks. prosody, figurative speech/humor, narrative coherence, context clues (social, emotional…).
right vs. left in neonates
right is just as active as left during language processing suggesting that, at birth, the brain is not left lateralized but as we age, the right stays the same and the left becomes stronger in language activation
phrenology
the idea that you can understand differences between people by looking at their scalp. completely incorrect but the notion that certain parts of the brain are responsible for certain things was correct.
traditional language areas
Broca’s area
located in the left inferior frontal gyrus (LIFG), language production
broca’s aphasia causes telegraphic speech (speech is very difficult, use contect words like a 1.5 year old)
Wernicke’s area
located in superior posterior temporal lobe, language comprehension
Wernicke’s aphasia: can speak a lot but it doesnt make sense
rethinking broca’s area
broca’s aphasics cannot match a sentence to a picutre that relies on sentence comprehension, not all broca’s aphasics have lesions in broca’s area, broca’s patients suffered most of thier damage outside of broca’s area, aphasia wasn’t always lasting (could overcome with language therapy), sujects asked to read and repeat words showed that broca’s is active before but not during word proudction -> Broca’s coordinates transmission of info bt cortical areas involved in language processing rather than being directly implicated in speech production. broca’s is active during stroop task -> resolves representational and interpretational conflict. Broca’s works as a cognitive control area: willpower, impulse control, the ability to focus on what you are currently trying to achieve even when there are distractions, the ability to supress noice and focus on what’s important, the ability to inhibit signal A in order to pay attention/ execute on signal B
electrocorticography (ECoG)
electrodes placed directly on the surface of the brain, measures electrical potential, great temporal resolution and spacial specificity (because the skull isnt in the way)
