1. Last Lecture Hemispheric differences in the Bisected Brain Hemispheric differences in the Bisected Brain Functions of the corpus callosum Functions of the corpus callosum Hemispheric Asymmetries in the Normal Brain Hemispheric Asymmetries in the Normal Brain Methods and theories Methods and theories

2. This Lecture Dichotic Listening Dichotic Listening The corpus callosum & resource allocation The corpus callosum & resource allocation Handedness Handedness Functions of the corpus callosum Functions of the corpus callosum The aphasias The aphasias

3. Announcements Quiz next week Quiz next week Study guide on the web after class today Study guide on the web after class today Cognitive Neuroscience chapter 8 only sections on Language and the Brain (303-312) Cognitive Neuroscience chapter 8 only sections on Language and the Brain (303-312)

4. ba ga ba ga left right -- Both ears project bilaterally Both ears project bilaterally Contralateral projection is stronger Contralateral projection is stronger With dichotic input the ipsilateral ear’s input is supressed. With dichotic input the ipsilateral ear’s input is supressed. -

5. Auditory Studies: Kimura’s Dichotic Listening Technique Requires different input to each ear (binaural) Requires different input to each ear (binaural) laterality effects are rare with monaural input. laterality effects are rare with monaural input.WHY? Ears project bilaterally Ears project bilaterally Monaural input --> both hemispheres get same stimulus so no differences emerge. Monaural input --> both hemispheres get same stimulus so no differences emerge. BUT Ipsilateral projection weaker than contralateral BUT Ipsilateral projection weaker than contralateral Different binaural input --> competition: contralateral pathway wins. Different binaural input --> competition: contralateral pathway wins.

6. Auditory Studies: Kimura’s Dichotic Listening Technique Auditory stimuli to left ear & right ear simultaneous and synchronized. Typical stimuli: Typical stimuli: nonsense syllables (ba, ga, da) nonsense syllables (ba, ga, da) digits digits melodic patterns melodic patterns nonspeech sounds nonspeech sounds Results: Results: Right Ear advantage- verbal stimuli; Right Ear advantage- verbal stimuli; LEA- nonverbal stimuli. LEA- nonverbal stimuli.

7. The Corpus Callosum and Processing Resources Resource: basic raw materials needed to get a task done. Resource: basic raw materials needed to get a task done. Each hemisphere has some competancy with most tasks. Each hemisphere has some competancy with most tasks. As task difficulty increases, both hemispheres are recruited to meet task demands. As task difficulty increases, both hemispheres are recruited to meet task demands.

8. Two Comparison Conditions Across Field Comparison (from Banich & Belger, 1989 ) Unilateral Processing Bihemispheric Processing + A B A Within Field Comparison A A B + A B A A A B

9. Three Levels of Task Difficulty + A B A Physical Identity Match: A-A Name Identity Match: A-a + A B A C D + A B a C D 3-Item Physical 5-Item Physical 5-Item Name 3-Item Physical 5-Item Physical 5-Item Name

10. Sometimes, Two Hemispheres are Better than One... For easier tasks within field matches are faster. For easier tasks within field matches are faster. For harder tasks across field matches are faster. For harder tasks across field matches are faster. 3-PI5-PI5-NI 250 350 450 550 650 750 WITHIN ACROSS Reaction Time

11. Functions of the Corpus Callosum Unify the sensory world Unify the sensory world e.g. copies of input e.g. copies of input Information transmission Information transmission to access specialized processors (more on this with case V.J) to access specialized processors (more on this with case V.J) to share products of cognitive processes to share products of cognitive processes Allocation of resources (Banich task) Allocation of resources (Banich task)

12. Handedness 10% of the population is Left Handed 10% of the population is Left Handed Left handers have different brain organization Left handers have different brain organization What is left-handedness?

13. Case V.J.- Clues to handedness (Baynes et al) a left hander w/ normal speech & language who underwent callosotomy. a left hander w/ normal speech & language who underwent callosotomy. After surgery: left hand single- letter writing - perfect left hand single- letter writing - perfect right hand entirely agraphic right hand entirely agraphic

15. Isolation of grapho-motor module In VJ, writing dissociates from other language abilities. In VJ, writing dissociates from other language abilities. Writing in RH Writing in RH All others LH All others LH In JW & VP all language abilities are co- localized in LH. In JW & VP all language abilities are co- localized in LH.

16. Implications of V.J. Writing module can be dissociated from other language modules. Writing module can be dissociated from other language modules. Handedness may depend on laterality of writing module. Handedness may depend on laterality of writing module. In all Left handers access to this RH module may require the c. callosum. In all Left handers access to this RH module may require the c. callosum. Laterality of other language modules may also vary in Left handers. Laterality of other language modules may also vary in Left handers.

17. What are the other components of language?

18. Components of Sound-based Language Phonemes - units of sounds that make up words Phonemes - units of sounds that make up words Morphemes - smallest unit of meaning Morphemes - smallest unit of meaning Syntax - grammar-- rules for combining words Syntax - grammar-- rules for combining words Lexicon - stored representations of words (auditory/visual) Lexicon - stored representations of words (auditory/visual) Semantics - meanings that correspond to lexical items Semantics - meanings that correspond to lexical items Prosody - intonation of speech (Right Hemisphere province) Prosody - intonation of speech (Right Hemisphere province) Articulation - movements of the mouth and vocal tract for producing speech Articulation - movements of the mouth and vocal tract for producing speech Discourse - Linking of sentences into coherent narrative. Discourse - Linking of sentences into coherent narrative. Production and comprehension of these components are required for language.

19. Broca's aphasia speech: labored, slow & nonfluent (awkward articulation, search for phonemes). speech: labored, slow & nonfluent (awkward articulation, search for phonemes). paraphasic errors (phonemic: pelsil for pencil) paraphasic errors (phonemic: pelsil for pencil) responses make sense but are ungrammatical. responses make sense but are ungrammatical. greatest difficulty: verbs, articles, pronouns (generating & repeating) --> telegraphic speech greatest difficulty: verbs, articles, pronouns (generating & repeating) --> telegraphic speech Comprehension is relatively spared Comprehension is relatively spared

21. Cookie Theft Picture (BDAE)

22. Lesion locus of Broca’s aphasia

23. Is Broca’s aphasia simply a problem with vocal-motor coordination? After all...Broca’s area is near motor face area... NO!! No dysfluency after hemifacial paralysis from RH damage No dysfluency after hemifacial paralysis from RH damage Dysarthria - a separate disturbance- lack of coordination of vocal track. Dysarthria - a separate disturbance- lack of coordination of vocal track.

24. Broca’s aphasia has cognitive/linguistic properties Better fluency for memorized phrases. Better fluency for memorized phrases. Singing may be more fluent than speech Singing may be more fluent than speech --> Melodic intonation therapy --> Melodic intonation therapy Why should coordination problems affect verbs/function words more than nouns??? Why should coordination problems affect verbs/function words more than nouns??? Written output shows same errors as speech! Written output shows same errors as speech! These features suggest more than a problem with vocal coordination.

25. Wernicke-Geschwind model Broca's a.: forms detailed coordinated plans for language production (spoken, written, covert/rehearsal) Broca's a.: forms detailed coordinated plans for language production (spoken, written, covert/rehearsal) Explains dysfluency and poor articulation Explains dysfluency and poor articulation But comprehension is not perfect... Schwartz, Saffran and Marin, 1980 Schwartz, Saffran and Marin, 1980 Poor syntax comprehension Poor syntax comprehension Broca's aphasics poor at judging grammaticality Broca's aphasics poor at judging grammaticality Active: The horse kicked the cow. Passive: The cow was kicked by the horse.

26. Agrammatism... difficulty using & understanding grammar difficulty using & understanding grammar Modification of the W-G model Broca's area: Plan for coordinating language production Plan for coordinating language production understanding and using syntax. understanding and using syntax. Active: The horse kicked the cow. Passive: The cow was kicked by the horse.

28. Wernicke's aphasia Speech: phonetically & grammatically normal but meaningless. Speech: phonetically & grammatically normal but meaningless. generally fluent, unlabored, well articulated. generally fluent, unlabored, well articulated. normal intonation (prosody). normal intonation (prosody). words used inappropriately, nonsense words (neologisms) --> "word salad" words used inappropriately, nonsense words (neologisms) --> "word salad" meaning expressed in roundabout way (circumlocution). meaning expressed in roundabout way (circumlocution). Cookie Theft description... "Mother is away here working her work to get better, but when she's looking into the two boys looking in the other part. She's working another time..." "Mother is away here working her work to get better, but when she's looking into the two boys looking in the other part. She's working another time..." Comprehension: severely impaired. Comprehension: severely impaired.

29. Interpretation of Wernicke's aphasia According to Wernicke-Geschwind model Wernicke's Area stores memories of sound sequences that constitute words. stores memories of sound sequences that constitute words. translates auditory input into phonological forms that can then access semantics. translates auditory input into phonological forms that can then access semantics. meaning is stored in other cortical areas meaning is stored in other cortical areas During spontaneous speech, "cognitive" areas send input to Wernicke's area: During spontaneous speech, "cognitive" areas send input to Wernicke's area: Cognition -> Wernicke's A. (22) -> arcuate fasciculus -> Broca's A. (44)-> Face area Cognition -> Wernicke's A. (22) -> arcuate fasciculus -> Broca's A. (44)-> Face area

31. READING

32. Reading According to the Wernicke-Geschwind model... Wernicke’s A. essential for reading... Visual processing --> Angular gyrus --> Wernicke's A.--> Semantics Visual processing --> Angular gyrus --> Wernicke's A.--> Semantics Angular G. (39) translates visual code to a form that can access auditory word code in Wernicke’s.A. Angular G. (39) translates visual code to a form that can access auditory word code in Wernicke’s.A. Semantics must be accessed via the auditory (phonological) form of the word. Semantics must be accessed via the auditory (phonological) form of the word. Implication: Reading requires phonological recoding via Wernicke’s area… or does it?? Implication: Reading requires phonological recoding via Wernicke’s area… or does it??

33. Posner, Peterson, Raichle and colleagues (1988) PET evidence challenges this account Posner, Peterson, Raichle and colleagues (1988) If auditory recoding is necessary for reading then If auditory recoding is necessary for reading then reading and listening should activate the same brain areas They do not... They do not... Implication- visual representation can access meaning directly Implication- visual representation can access meaning directly READING LISTENING