Language

components of language

phonemes: sounds of language

semantics: meaning of language

grammar: rules of language

discourse:sentences & paragraphs

pragmatics: practical information abt language & language use

core language areas

• wernicke’s area

• broca’s area

semantic regions of language

• L middle temporal gyrus

• L angular gyrus

• L anterior temporal lobe

• L anterior inferior frontal gyrus

cause of broca’s aphasia

lesion of brocas areas

impairments from broca’s aphasia

• speech production deficit

  • halting

  • short utterances

  • disordered grammar & syntax

• patients know what they want to say, comprehension is in tact

• reading ok

• writing limited

wernicke’s aphasia cause

• lesions around left post STG near primary audit cortex

wernicke’s aphasia impairement

• language comprehension deficit

  • nonsensical speech output (invented words)

  • patients do not comprehend their speech

• fluent and well-structured speech that doesn’t make sense

• reading & writing severly impaired

where does micro-stimulation interfere w language

• LH dominant for language

• language area localization variable

  • sites outside of broca’s & wernicke’s areas

what does skeide & friederici’s model of speech comprehension propose

• sound associated with the letters are in the auditory cortex

• the meaning of a word is the anterior temporal region

• broca’s area provides the meaning of sentences by finding the relationship between the meaning and grammatical structure of the words in the sentence

• the emotional tone is processed in the RH

what does hickok & poeppel state

speech perception & production rely on 2 pathways

• ventral stream (what pathway)

• dorsal stream (how pathway)

ventral stream in language (hickock & poeppel)

understanding the meaning of a word or sentence

• sound = meaning

  • converts acoustic speech signals into lexical semantic representations

• function = speech comprehension

• where = middle & inferior temporal areas

dorsal stream (how) (hickock & poeppel)

• speech production

• where: posterior frontal regions & parietal areas

• sound: articulation

  • links auditory representations of speech with motor systems for speech production

• function: sensorimotor integration

when does N400 amplitude increase

• unexpected words

• semantic anomalies

• words diff to integrate

N400 amplitude decreases with

• word position in a sentence

• repetition

• relatedness (becomes more expected)

what does N400 convey

neural effort needed to access and integrate the meaning of a word given its context

what is an animacy violation?

an object acting as a living thing

example the discourse elimate the effect of an animacy violation of an N400

childrens stories

when does the P600 wave peak?

500-800 ms after the onset of an eliciting word

when does p600 wave increase

• ungrammatical words in a sentence

• grammatical but not preferred words given the syntactic context

waht does P600 posterior wave reflect

• attempts to revise structure

• syntactic integration difficulty in general

example of monkey calls as a rudimentary precursor of human language

one group of monkeys warn about a land predator while another warns of an eagel above

difference between human and non-human primates for evolutinoary precursor of our language network

language areas btwn humans and non-human primates suggest that latter lacks key connections involving anterior inferior temporal lonbe

what ability do infants lose by ~1 year of age?

ability to discriminate and produce all phones/phonemes, but lose it after exposure to particular subset of speech

critical period of language acquistion

age 10

genie case

• social isolation, no exposure to language

• 13 years old, couldn’t learn grammar

noam chomksy universal language

deep language structure that is shared among all languages

language acquisition device

proposed idea that the preparedness for acquiring language is innate & neural

what was cause of split brain patients?

• alleviated epileptic seizures by cutting matter fibers connecting the two hemispheres, the corpus callosum

• fully disconnected

• explored L & R hemisphere independently

• once cut can’t transfer info

how do split brain patients process verbal & nonverbal stimuli

• Right visual field → Left hemisphere (has language): Can name what they see AND pick a matching card with the right hand.

• Left visual field → Right hemisphere (no language): Can't name what they see, but the left hand can still pick the correct associated card showing the right hemisphere understands the image, it just can't speak.

leads to LH interpreting what the RH did

split brain patients & vision

• can name objects projected in L hemisphere

• cannot name in R hemi

split brain patients somatosensory perception

• can name obejects touched with R hand (L hemi)

• hard time describing L hand (R hemisphere)

role of right hemisphere in speech

• rudimentory speech

• importnat for prosody (emotion in speech)

Wada test

• short acting anesthetic injected into left cartid artery of individual perofmring verbal task

• if LH is dominant lang then indiv becomes transiently aphasic for a few mins before anesthetic is diluted