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Language

Language. References: Kutas M., Hillyard SA., Reading Senseless Sentences: Brain Potentials Reflect Semantic Incongruity, Science, Vol 207, pp.203-205, 1980 Price, C., The Anatomy of Language: Contributions from Functional Neuroimaging, Journal of Anatomy, Vol. 197, pp. 335-359, 2000

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Language

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  1. Language

  2. References: Kutas M., Hillyard SA., Reading Senseless Sentences: Brain Potentials Reflect Semantic Incongruity, Science, Vol 207, pp.203-205, 1980 Price, C., The Anatomy of Language: Contributions from Functional Neuroimaging, Journal of Anatomy, Vol. 197, pp. 335-359, 2000 Bookheimer, S., Functional MRI of Language: New approaches to understanding the cortical organization of semantic processing, Annual Reviews Neuroscience, vol 25, pp.151-188, 2002 Demonet JF, Thierry G, Cardebat D., Renewal of the Neurophysiology of Language: Functional Neuroimaging, Physiological Reviews, Vol 85, pp.49-95, 2005 Marien P, Engelborghs S, Fabro F, DeDeyn PP, The Lateralized Linguistic Cerebellum: A review and a new hypothesis, Brain and Language, Vol 79, pp.580-600, 2001 Wierenga C., Maher LM, Moore AB, White KD, McGregor K, Soltysik D, Peck KK, Gopinath K, Singletary F, Gonzalez-Rothi L, Briggs R, Crosson B, Neural Substrates of Syntactic Mapping Treatment: An fMRI study of two cases, Journal of the International Neuropsychological Society, Vol 12, pp.132-146, 2006 Evolutionary Anatomy of the Primate Cerebral Cortex, Eds. Dean Falk, Kathleen Gibson, Cambridge University Press, 2001 The Cognitive Neurosciences III, Ed. Michael Gazzaniga, MIT Press, 2004, Chapter 1: What is it like to be human, Todd Preuss

  3. Early studies in morphology

  4. Asymmetry of the planum temporale and lateralization Lateralization: Functional specification of local areas wtihin hemispheres * Hand bump area in Chimp, but not macaque * Handedness: Observed in chimps, but equally distributed in entire population. In humans, for 95% of right handers, language is in LH (for 70% of left handers, language is in LH)

  5. Planum temporale (PT) Gazzaniga PT: Area of Sylvian fissure posterior to the Heschl's gyrus (primariy auditory cortex)

  6. Structural asymmetry of the PT Falk & Gibson

  7. Structural asymmetry of the PT present in chimp and human: L>R Falk & Gibson

  8. Early studies in function

  9. First neuroimaging study in language Kutas & Hillyard, Science, 1980

  10. First neuroimaging study in language attention Note the difference from oddball (P300) N400 language comprehension Kutas & Hillyard, Science, 1980

  11. Evolutionary perspective

  12. As brain gets bigger, more cortical areas must be added For Ex: More than 50 Broadmann areas in human, but about 20 in Old world monkeys Gazzaniga Corbalis' explanation for evolution of language: Chimps are quadripedal. Transfer of humans to bipedalism was a huge step. Humanoids started to roam, and needed speech to communicate to free hands from gesturing (--->complex tool making) Area for mirror neurons and gesturing, both in chimps and humans

  13. Localization of Language

  14. * RH is activated for non-semantic sounds, LH for words Demonet, 2005

  15. Visual word forms Speech generation Motor image of speech Auditory image of speech Auditory input (Heschl's gyrus) 19th century model of language for single words Price, 2000

  16. Inputs: Auditory Visual Tactile (Braille) • 3 types of memory needed for language: (C. Price) • Phonological (sounds) • Ortographic (spelling) • Semantic (knowledge) Output: 1. Self-initiated 2. Stimulus driven (response to written on heard words)

  17. Semantic knowledge Basal temporal language area: BA19, BA37, BA20 Demonet, 2005

  18. Concept centre: INPUTS = semantic categories OUTPUTS Price, 2000

  19. Semantic categories 20th century model of language for single words based on behavioral data Price, 2000

  20. Not accounted for, in these models: Price, 2000

  21. for language Newly proposed model which accounts for dyslexia basal temporal language area route2 route1 2 routes: Damage in route1: surface dyslexia Damage in route2: phonological dyslexia Price, 2000

  22. Development of the proposed model: word repetition Note bilateral activity !!! (Posterior IFG)

  23. Development of the proposed model: speech input/output (word deafness occurs if bilateral lesions present in these areas of PAC) critical speech production region word retrieval: picture naming verbal fluency

  24. Development of the proposed model: reading Accessing semantics in sentences

  25. Development of the proposed model: repetition versus reading

  26. Development of the proposed model: semantic knowledge angular gyrus:semantic processing Price,2000

  27. Specialization areas in IFG: (Bookheimer, 2002) * There is functional heterogeneity among Broca's aphasics in terms of impairments * Three dissociated areas in L IFG are found: 1. Anterior IFG = retrieval of semantic information 2. Middle IFG = syntax (complexity α WM load) 3. Posterior IFG = phonology (sensorimotor encoding of auditory input) * Example tasks: Given two sentences with a change in: - 1 word (semantic task): he went to the store vs he went to the school - word order (syntactic task): the west of the cinema is store store is the west of the cinema find if two sentences have the same meaning - Active/Passive: A lion was fatally attacked by the tiger. or The tiger fatally attacked the lion Question: Which animal died ? (passive sentence is difficult for aphasics) - Given a word break it down in to phonemes (phonologic task)

  28. Bookheimer,2002

  29. Non-language roles proposed for IFG: * Studies indicate area 44 in humans is similar to area F5 in monkeys which contain mirror neurons * It is also thought that imitation is an essential step for developing language * BA 44 activates in humans when they imagine to observe a movement * Hence BA 44 is not specialized for just language but also for imitation of complex movements, which embodies speech planning * In addition, IFG activates for some tone discrimination tasks as well * This indicates that the phonological role assumed by IFG is not speficic to language

  30. Right Hemisphere

  31. * Judging whether a sentence contains metaphors (ex: Investors were squirrels collecting nuts) caused greater activations in R IFG, and R post. sup. temp. gyrus. Same RH areas activated in addition to areas in LH, when subjects tried to determine the moral lesson of a passage * In one study, passages are presented with or without titles. The passages indirectly used the title to convey information, without the titles, passages did not make sense. Extensive RH activity was observed in all language areas for passages without titles * LH is powerful for tracking sequential logic, but RH is powerful for keeping a holistic understanding of a talk (topic maintanence) (seq logic: If A is B and B is C then A is C) (top. maint.: Dou you believe in angels? Yes I have my own angel) * In a few studies, R IFG activated for processing sentences with prosody versus neutral sentences * From these studies, it seems RH has a critical role in language comprehension and a global understanding of semantic context Bookheimer, 2002

  32. L R ? Bookheimer,2002

  33. Cerebellum

  34. Lateral cerebellum sends to and receives from contralateral BA 6,44, 45 through thalamus and pons respectively In word generation studies R lateral cerebellum which connects to L PFC activates consistently In patients with R cerebellar damage there are deficits in semantic word generation, phonological generation, and syntactic processing It is speculated that cerebellar damage causes diminished or abolished function of remote language zones due to reduced input through cerebellocortical pathways (diaschisis) Marien, 2001

  35. Marien, 2001

  36. Patient studies

  37. Applications of neuroimaging in aphasia patients: Sentence production Infarct in LH Chronic, non-fluent aphasia, 53. months after onset rehabilitation Active sentences Passive sentences C. Wierenga, 2006

  38. Sentence production fMRI fMRI: ON - sentence production wrt given picture as in learning set OFF- watching non-sense picts C. Wierenga, 2006

  39. Absence of Planum temporale asymmetry n=15 autism adults, 15 control Rojas

  40. Worthy of note

  41. Problem of precise localization in a word generation study Task: * Silently generate words for a given category (no speech) * Auditory stimuli * Example Category: “farm animals” Paradigm: * Block * Timing:17.5 sn on & off (rest) * Repetitions: 6 Subjects: * 15 M, 13 F students * Age: 26.4 (sd:7.1) Data collection: * 1.5T GE MR scanner * fMRI: Nine 6.5 mm thick slices, 64 images each gradient echo spiral scan Analysis: AFNI (MCW)

  42. Anatomy Overall activity CS/PCS activity Without PCS With PCS Results obtained with LOFA same area after smoothing in 28 subj * Nüfusun %75 indePCS var * PCS var ise CS kelime üretmede yeralmaz Activity is located in PCS, whenever there is a PCS present B. Crosson, 1999

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