The cognitive neuroscience of language comprehension

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The cognitive neuroscience of language comprehension

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1. The cognitive neuroscience of language comprehension

2. Uniqueness of language Separates humans from other animals Other ‘unique’ human abilities have been found in other animals. Tool use Cooperation Use of symbols Theory of mind

3. Animal language studies Parrots Dolphins Dogs Apes Orangutans Gorillas Chimpanzees Bonobos

4. Chimpanzees Several researchers have attempted to raise chimpanzees as a member of the family (e.g., Kellog, Hayes). Chimpanzee could learn to recognize more than 100 words. Chimpanzees are not able to produce sounds used in human language.

5. Bonobo language learning Kanzi and Sue Savage-Rumbaugh

6. Language learning in Bonobos Learned a few hundred ‘lexigrams.’ Also learned to comprehend some spoken English as well as a 2.5 year old child.

7. Lexical vs. grammatical ability in children Lexical growth and grammatical ability strongly correlate (Bates and Goodman, 1997).

8. Subcomponents of language Sound Phonemes Lexical access (semantics, word class of individual word,. Results: Using eye tracking very few regressive eye movements.

9. Classic model of language processing in the brain Wernicke-Lichthiem-Geschwind model

10. Types of aphasia Broca’s aphasia:difficulty producing words Wernickes’s aphasia: difficulty comprehending words. Conduction aphasia: difficulty repeating words or correcting mistakes. Global aphasia (transcortical aphasia): difficulty comprehending and producing words.

11. Broca’s aphasia The patient is talking about why he came to the hospital – Yes ... ah ... Monday .... ah .... Dad and Peter Hogan, and Dad .... ah .... hospital .... and ah .... Wednesday .... Wednesday nine o'clock and ah Thursday ... ten o'clock ah doctors ... two .... two .... an doctors and .... ah .... teeth .... yah .... And a doctor an girl .... and gums, an I. From 'The Shattered Mind' by Howard Gardner.

12. Wernicke’s aphasia "What brings you to the hospital? ... "Boy, I'm sweating, I'm awful nervous, you know, once in a while I get caught up, I can't mention the tarrripoi, a month ago, quite a little, I've done a lot well, I impose a lot, while, on the other hand, you know what I mean, I have to run around, look it over, trebbin and all that sort of stuff." ... "Thank you, Mr. Grogan. I want to ask you a few -" "Oh, sure, go ahead, any old think you want. If I could I would. Oh, I'm taking the word the wrong way to say, all of the barbers here whenever they stop you it's going around and around, if you know what I mean, that is tying and tying for repucer, recuperation, well, we were trying the best that we could while another time it was with the beds over there the same thing ..." From 'The Shattered Mind' by Howard Gardner.

13. Modifications to W-G model Beyond the word level Broca’s aphasics often have problems in comprehension of syntactically complex sentences. Reexamination of neuropsychological evidence

14. Broca’s aphasics and syntactic complexity The brown horse is chased by the white dog. (Caramazza & Zurif, 1976) The brown horse chased the white dog. (Schwartz, Saffran, & Marin, 1980).

15. Broca’s aphasia Two possibilities to explain syntactic deficits: Loss of syntactic knowledge? Inability to access syntactic knowledge?

16. Difficulty accessing syntactic knowledge Broca’s aggramatic aphasics can judge grammaticality of sentences. *The brown dog chase the white horse. The brown dog chases the white horse.

17. Neuropsychological evidence Original model made before modern neuroimaging technology CAT scanning of Broca’s patient “Tan’s” brain shows that lesion includes BA 44,45,47, anterior insula, basal ganglia, and white matter tracts.

18. Neuropsychological studies Behavior based studies Lesions not including Broca’s area can produce Broca’s aphasia. Lesion based studies Patients with lesions in Broca’s area without Broca’s aphasia. Voxel-based lesion symptom mapping (Bates et al., 2003)

19. Dronker’s et al. (2004) VLSM study Tested 64 LH lesion patients in sentence comprehension battery (CYCLE-R) and compared results with RH lesion, and older control subjects.

20. Behavioral stimuli


23. Summary of VLSM mapping results 5 general areas involved in sentence processing Medial temporal gyrus Anterior BA22 Superior temporal sulcus/BA39 BA46 BA47 Neither Wernicke’s nor Broca’s area implicated.

26. Summary of Dronkers et al. (2004) Medial temporal gyrus important for word level comprehension. Anterior BA22 important for simple syntax, and basic morphosyntax. Frontal areas important for working memory used during sentence comprehension. Angular gyrus needed for verbal short term memory and auditory rehearsal.

27. Neuroimaging studies Individual word level Sentence level semantics Sentence level syntax

28. Semantics Number of propositions in a sentence (Caplan et al., 1998) (bilateral superior and medial temporal lobes) Jabberwocky versus sentences with content English: Betsy can eat the apple at this park. Jabberywocky: Bapfa can eeg the agger at this pilt. (source: Neville lab, University of Oregon) Detection of semantic errors compared to detection of other errors

29. Examples of sentence conditions used in Friederici et al. (2003). Correct condition Das Hemd wurde gebügelt The shirt was ironed Syntactic violation condition Die Bluse wurde am gebügelt The blouse was on ironed Semantic violation condition Das Gewitter wurde gebügelt The thunderstorm was ironed Correct filler condition Der Rock wurde am Freitag gebügelt The skirt was on Friday ironed

31. Syntax Kaan and Swaab (2002) review neural basis of syntax. Complex versus simple sentences. Simple: The child spilled the juice that stained the rug. Complex: The juice that the child spilled stained the rug. Sentences compared to word lists. Jabberwocky versus pseudoword lists. Detection of syntactic errors.

32. Complex versus simple sentences

33. ERP studies Semantics N400 Syntax LAN P600/SPS

34. N400 Kutas and Federmeir (2000)

35. N400 (2)

37. Summary The Wernicke-Geschwind model is being replaced by new models. New models focus on both neural basis and timing of language comprehension, and have moved beyond simplistic divisions of comprehension/production. rent priorities on cues for sentence comprehension. In Italian: inflectional morphology > word order > ... In English word order > inflectional morphology...

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