Neural Correlates of Nouns and Verbs: fMRI Study Design
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Neural Correlates of Nouns and Verbs: fMRI Study Design

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Presentation in BCBL, fMRI investigation aiming to provide insight into the neuro-correlates of nouns and verbs.

Presentation in BCBL, fMRI investigation aiming to provide insight into the neuro-correlates of nouns and verbs.

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  • What BAs?Also here you could add some brain images from studies (or lesion studies) showing the involvement of this regions for nouns and verbs.Also, someone might wonder: Does this mean that nounrs do not rely at all on PFC regions, and verbs do not depend on lateral temporal cortex? It would be good to mention something about this during your presentation.
  • For lesion studies, these areas of damage are associated with these classes-overlap in the LIFG, we know this is strongly related to noun and verb processing.-can we pick apart this area for separation?-there are exceptions
  • -Most consistent activation for nouns and verbs is in LIFG-BUT, there’s been inconsistencies, some show separation, some don’t
  • Above imaginabilityDifferent semantics are different; tools, animals, fruits differentphonological, orthographic, lexical, semantic or lexical-syntactic level,
  • What are the baselines?
  • Lateral temporal – Planned comparisons in each task, based on the studies, what activation do we expect?Refined neuro-hypothesis.44, 45, 47.Pub.med.Visual occipital.
  • Delete the final collum
  • 300-500ms before word presented, and time after so that the response is within what is captured. TR
  • Pseudo-randomised sequence ITI (1 – 10 secs)Each word presented for 1000msRespond within 2000ms
  • This is great, Laura.Despite that the two tasks are consecutive, it would be very important to indicate the subjects what task they are at, which is not possible to infer from the presentation of the (same) wordFor doing so, you can for instance use colors or anything disctintive. You can say that participants will be trained on the task with fillers before going into the scanner, so they will learn the rules beforehand (e.g., blue is lexical task, and green is categorical task). You can also say that you will counterbalance the colors use per each rule/task across subjects.
  • TR 2 seconds (time repetition)7 conditions960 stimuli presentation.Inter fixation is when there’s nothing on the screen, but they look at it between trials.Total duration 1248 seconds. 21 minutes. Each functional run should be 6.9 minutes (3 runs).208 volumes per functional run.paramtersTR 2TE 20 – 40ms (25 or 30 is standard)field of view: 192mmthickness of slices and voxel size 3x3x3mmmatrix: 64 x 6433 slices to cover whole brain in the 2 secondsInterleave slice acquisition, no gap.T1 because lower TR
  • Visual – so, visual cortex?If have to press a button, then the motor cortex on the opposing side to the button being pressed (will need to counter-balance this)Semantic activation, syntactic activationVisual word-form area (fusiform gyrus)Brodmann area 17 and 18, 19, visual cortex4 and 6 – motor cortexBrodmann area 44 – semanticsBrodmann area 45 – semantics, generating verbs from nounsBrodmann area 47 - syntax
  • Whole brain t contrastfor this planned comparison, where will there be more activation and why.Syntax – bilateral temporal cortex – Friederici et al.,
  • Lateral temporal – Planned comparisons in each task, based on the studies, what activation do we expect?Refined neuro-hypothesis.44, 45, 47.Pub.med.Visual occipital.

Neural Correlates of Nouns and Verbs: fMRI Study Design Neural Correlates of Nouns and Verbs: fMRI Study Design Presentation Transcript

  • Neural Correlates ofNoun and VerbCharacteristicsLaura Gwilliams
  • Research Question: Which lexical elements can neurologically distinguish between nouns and verbs?
  • Theoretical BackgroundLesion Studies• Anomia can affect verbs and nouns separately• Functional independence ≠ anatomical independence?• Verbs: • Pre-frontal cortex (BA 45) • Frontal regions (BA 44) • Posterior Left Inferior Frontal Gyrus (IFG, BA 47)• Nouns • Anterior temporal cortex (BA 38) • Middle temporal cortex (BA 21) • Inferior temporal regions (BA 20) Cappa and Perani, Journal of Neurolinguistics, 2003
  • Theoretical Background Verbs NounsLeft Inferior Frontal Gyrus
  • Theoretical BackgroundfMRI Studies• Main activation located in the Left Inferior Frontal Gyrus• Processing syntactic information (Friederici et al., 2000) • (functional vs. content words) • Processing inflected verbs and nouns (Tyler et al., 2004) • Decomposition of morphologically complex items (Tyler et al., 2002)• Inconsistent results Wong & Chen, Language and Cognitive Processes, 2012
  • Issues in Previous Studies DINING + LEAPING vs. WRENS + WEASELS• QUESTIONS: • Semantic differences? • Stem or Suffix? • Task employed?
  • Design• Combine two tasks: • 1) Lexical decision (word / non-word) • 2) Grammatical classification (noun / verb)• Compare words which differ in relation to their • Verbal stem • Nominal suffix • Semantics
  • Materials: Stimuli Item Verb Stem Nominal Suffix Semantics Nominalization Action (Argument) Event Noun Action (Avalanche) Pseudo-Suffix Action (Excursion) Prototypical Noun Object (Elephant) Prototypical Verb Action (Argue)
  • Planned Comparisons Item Verb Stem Nominal Suffix Semantics Nominalization Action (Argument) Pseudo-Suffix Action (Excursion)• Allows for insight into decompositionality of items
  • Planned Comparisons Item Verb Stem Nominal Suffix Semantics Nominalization Action (Argument) Prototypical Verb Action (Argue)• Comparing same verbal stem, but with different grammatical behaviour
  • Planned Comparisons Item Verb Stem Nominal Suffix Semantics Event Noun Action (Avalanche) Prototypical Noun Object (Elephant)• Comparing ‘action’ vs. ‘object’ semantics
  • Event-Related DesignStimuli 1 Stimuli 3 Stimuli 2
  • Design StimuliNominalizations Consonant StringsEvent Nouns Lexical Decision Pseudo-wordsPseudo-suffixProto-nouns Word Non-WordProto-verbs Noun Stimuli Grammatical Categorisation Verb
  • • 40 stimuli per condition Design • 7 conditions • Colours and hands counterbalanced 1000ms + ITI randomised 1 – 10 seconds LeccionWord / Non-Word? + 1000ms Leccion Noun / Verb? +
  • fMRI Data Acquisition• 3 Tesla Siemens whole body MRI scanner• 32-channel coil• Each fMRI session will consist of 208 volumes per run, 33 slices each• Spatial pre-processing: • correct for Slice Timing first, then Realign and Unwarp images.Parameters• TR: 2000ms• Interleave slice acquisition with no gap• TE: 25ms• Field of view: 192mm• Voxel size 3x3x3mm• Matrix: 64x64mm• T2*-weighted images
  • Neuroanatomical Predictions MotorSyntax Semantics Visual Visual word form area
  • Neuroanatomical PredictionsVerb Stem Nominal Suffix SemanticsArgument/Excursion Argument/Argue Avalanche/Elephant BA 44 and 45: Semantic and decompositional difference BA 47: Syntactic difference BA 44 and 45: Semantic difference Task?
  • Wrap-upItem Verb Stem Nominal Suffix SemanticsNominalization Action(Argument)Event Noun Action(Avalanche)Pseudo-Suffix Action(Excursion)Prototypical Noun Object(Elephant)Prototypical Verb Action(Recuperate) • Similarities in activation may determine what is processed as ‘syntactic’ or ‘semantic’ • Inconsistencies in verb/noun location overcome by more specific stimuli characteristics • Identify whether different tasks cause different activation
  • ReferencesAron, A. R., Robbins, T. W., & Poldrack, R. A. (2004). Inhibition and the right inferiorfrontal cortex. Trends in cognitive sciences, 8(4), 170-177.Cappa, S.F., & Perani, D. (2003). The neural correlates of noun and verb processing.Journal of Neurolinguistics, 16, 183-189.Friederici, A. D., Meyer, M., & Von Cramon, D. Y. (2000). Auditory languagecomprehension: an event-related fMRI study on the processing of syntactic and lexicalinformation. Brain and language, 74(2), 289-300.Tyler, L. K., Randall, B., & Marslen-Wilson, W. D. (2002b). Phonologyand neuropsychology of the English past tense. Neuropsychologia, 40, 1154–1166.Tyler, L. K., Bright, P., Fletcher, P., & Stamatakis, E. A. (2004). Neural processing of nounsand verbs: the role of inflectional morphology. Neuropsychologia, 42(4), 512-523.Wong, A. W. K., & Chen, H. C. (2012). Is syntactic-category processing obligatory in visualword recognition? Evidence from Chinese. Language and CognitiveProcesses, 27(9), 1334-1360.
  • Thank you!