Short-Term Reorganization of Auditory Analysis Induced by Phonetic Experience Liebenthal et al. (2003). JoCN.MRI: physicsSlide 3MRI: procedureFunctional MRIConnection to neural activity?ProsConsPhonetic perceptionPast ResearchProblem!…Sinewave speech!Original sentenceSinewave speech: propertiesPast studies on sinewave speechTone-matching Task (Remez et al., 2001)Creation of stimuliSpectrogram of StimuliPilot studiesStimuli: summaryExperimental DesignProcedureSlide 23Results: RTResults: AccuracyResults: Phonetic Form PracticeResults: Subjective ReportsConclusions: BehaviorWithin each block…Image acquisitionfMRI ImagesfMRI analysis: individualsfMRI analysis: averagingfMRI analysis: significance testingfMRI Result SummarySlide 36Phonetic: Informed-NaivePhonetic ExperiencePhonetic Experience cont’dSlide 40Unexplained ResultsNonphonetic: Informed-NaivePhonetic: Blocks2-Blocks1Nonphonetic: Blocks1-Blocks2Proficiency EffectsWhat do YOU think?Conclusions…?Methodology…?Some questions…Some more questions…AcknowledgementsReferencesReferences: cont’dShort-Term Reorganization of Auditory Analysis Induced by Phonetic ExperienceLiebenthal et al. (2003). JoCN.Short-Term Reorganization of Auditory Analysis Induced by Phonetic ExperienceLiebenthal et al. (2003). JoCN.Audrey Kittredge593: Neuroimaging of LanguageAudrey Kittredge593: Neuroimaging of LanguageMRI: physicsMRI: physicsHydrogen nuclei act as magnets (spinning, charged particle)Hydrogen nuclei act as magnets (spinning, charged particle)MRI: physicsMRI: physicsIn strong magnetic field: spin-axes form vector parallel to fieldIn strong magnetic field: spin-axes form vector parallel to fieldMRI: procedureMRI: procedureRadio Frequency pulseChanges direction and strength of vectorEventually, nuclei relax and vector returns to original positionAs nuclei relax, give out pulsePulse type depends on water/fat ratio of tissue --> MRI images!Radio Frequency pulseChanges direction and strength of vectorEventually, nuclei relax and vector returns to original positionAs nuclei relax, give out pulsePulse type depends on water/fat ratio of tissue --> MRI images!Functional MRIFunctional MRIHemoglobin shows up better than deoxyhemoglobin on MRI SOBrain areas with more oxygenated blood will show up better (BOLD)Hemoglobin shows up better than deoxyhemoglobin on MRI SOBrain areas with more oxygenated blood will show up better (BOLD)Connection to neural activity?Connection to neural activity?Increase in net neural activity --> increase in oxygenated blood supply (slow)Quick succession of images: BOLD signal at various timesIncrease in net neural activity --> increase in oxygenated blood supply (slow)Quick succession of images: BOLD signal at various timesProsProsGood spatial resolutionLess risky, faster acquisition than PETEvent-related designGood spatial resolutionLess risky, faster acquisition than PETEvent-related designConsConsPoor temporal resolutionBOLD signal degraded near air/bone boundaryMovement artifactsHigh speed data acquisition = noisy!Poor temporal resolutionBOLD signal degraded near air/bone boundaryMovement artifactsHigh speed data acquisition = noisy!Phonetic perceptionPhonetic perceptionHow does this occur?Automatic phonetic analysis module (Liberman & Mattingly, 1989)Stimulus-independent auditory analysis (Kluender & Greenberg, 1989)How does this occur?Automatic phonetic analysis module (Liberman & Mattingly, 1989)Stimulus-independent auditory analysis (Kluender & Greenberg, 1989)Past ResearchPast ResearchPET, fMRI studies Speech vs nonspeech: superior temporal cortexPET, fMRI studies Speech vs nonspeech: superior temporal cortexProblem!Problem!Confound: perception or stimuli?Goal: study perception mode independent of stimulus propertiesHow do we do this?…Confound: perception or stimuli?Goal: study perception mode independent of stimulus propertiesHow do we do this?……Sinewave speech!…Sinewave speech!Sinewave exampleSinewave exampleOriginal sentenceOriginal sentence“The steady drip is worse than a drenching rain”“The steady drip is worse than a drenching rain”Sinewave speech: propertiesSinewave speech: propertiesSinusoid fit to center frequency and amplitude (over time) of F1-F3 or F4Result: rapidly changing pure tonesLack fine-grained acoustic properties of speechSinusoid fit to center frequency and amplitude (over time) of F1-F3 or F4Result: rapidly changing pure tonesLack fine-grained acoustic properties of speechPast studies on sinewave speechPast studies on sinewave speechRemez et al. (1981):“Describe”: most say non-speech“Transcribe”: most write all/some of sentence correctlyRemez et al. (1981):“Describe”: most say non-speech“Transcribe”: most write all/some of sentence correctlyTone-matching Task(Remez et al., 2001)Tone-matching Task(Remez et al., 2001)StimuliSinewave word e.g. juiceIsolated T2 from T123/4 complexTask: is tone constituent of complex?Listeners can do this…When uninformed (not speech)While matching tone complex to printed wordDifficult task!StimuliSinewave word e.g. juiceIsolated T2 from T123/4 complexTask: is tone constituent of complex?Listeners can do this…When uninformed (not speech)While matching tone complex to printed wordDifficult task!Creation of stimuliCreation of stimuliPhonetic stimulus (sinewave word)3 lowest formants = 1 sinewave each Tone probe“True”: from word“False”: from other sinewave wordNonphonetic stimulusT1 and T3 temporally reversedPhonetic stimulus (sinewave word)3 lowest formants = 1 sinewave each Tone probe“True”: from word“False”: from other sinewave wordNonphonetic stimulusT1 and T3 temporally reversedSpectrogram of StimuliSpectrogram of StimuliPilot studies Pilot studies Phonetic transcribed 52.1% accuracy, multiple choice 89.5% accuracyRated as “Clearly identifiable word”: 61% phonetic22% nonphonetic“Nonspeech”: 58% nonphonetic20% phoneticPhonetic transcribed 52.1% accuracy, multiple choice 89.5% accuracyRated as “Clearly identifiable word”: 61% phonetic22% nonphonetic“Nonspeech”: 58% nonphonetic20% phoneticStimuli: summaryStimuli: summary288