neural correlates of nouns and verbs: fmri study design
DESCRIPTION
Presentation in BCBL, fMRI investigation aiming to provide insight into the neuro-correlates of nouns and verbs.TRANSCRIPT
Neural Correlates of Noun and Verb CharacteristicsLaura Gwilliams
Research Question:
Which lexical elements can neurologically distinguish between
nouns and verbs?
Theoretical Background
• 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)
Lesion Studies
Cappa and Perani, Journal of Neurolinguistics, 2003
Theoretical Background
Verbs
Nouns
Left Inferior Frontal Gyrus
• 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
Theoretical BackgroundfMRI Studies
Wong & Chen, Language and Cognitive Processes, 2012
Issues in Previous Studies
• QUESTIONS:• Semantic differences?• Stem or Suffix?• Task employed?
DINING + LEAPING vs. WRENS + WEASELS
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: StimuliItem Verb Stem Nominal Suffix Semantics
Nominalization(Argument)
Action
Event Noun(Avalanche)
Action
Pseudo-Suffix(Excursion)
Action
Prototypical Noun(Elephant)
Object
Prototypical Verb(Argue)
Action
Planned Comparisons
Item Verb Stem Nominal Suffix Semantics
Nominalization(Argument)
Action
Pseudo-Suffix(Excursion)
Action
• Allows for insight into decompositionality of items
Planned Comparisons
Item Verb Stem Nominal Suffix Semantics
Nominalization(Argument)
Action
Prototypical Verb(Argue)
Action
• Comparing same verbal stem, but with different grammatical behaviour
Planned Comparisons
Item Verb Stem Nominal Suffix Semantics
Event Noun(Avalanche)
Action
Prototypical Noun(Elephant)
Object
• Comparing ‘action’ vs. ‘object’ semantics
Event-Related Design
Stimuli 1
Stimuli 2
Stimuli 3
DesignStimuli
Stimuli
Word Non-Word
Noun
Verb
Lexical Decision
Grammatical Categorisation
Consonant Strings
Pseudo-words
Nominalizations
Event Nouns
Pseudo-suffix
Proto-nouns
Proto-verbs
Design
+
Leccion
+
Leccion
+
Word / Non-Word?
Noun / Verb?
1000msITI randomised1 – 10 seconds
1000ms
• 40 stimuli per condition• 7 conditions• Colours and hands counterbalanced
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
Semantics
Syntax
Visual
Motor
Visual word form area
Neuroanatomical PredictionsVerb Stem Nominal Suffix Semantics
Argument/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 Semantics
Nominalization(Argument)
Action
Event Noun(Avalanche)
Action
Pseudo-Suffix(Excursion)
Action
Prototypical Noun(Elephant)
Object
Prototypical Verb(Recuperate)
Action
• 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 inferior frontal 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 language comprehension: an event-related fMRI study on the processing of syntactic and lexical information. 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 nouns and 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 visual word recognition? Evidence from Chinese. Language and Cognitive Processes, 27(9), 1334-1360.
Thank you!