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Module 2: Audition to Language Weeks 4-5 1 Tract of the talk How do we get to language Basic components for/of language Physical requirements for vocal language Cognitive requirements for language 2 ...

Module 2: Audition to Language Weeks 4-5 1 Tract of the talk How do we get to language Basic components for/of language Physical requirements for vocal language Cognitive requirements for language 2  involvement motorcontrolmuch motorcortex Physical requirements for language (vocal) Vocal chords in the larynx produce sound Thesoundcarrymeaning – Sound is filtered (changed) by the vocal tract Vocal tract includes: – pharyngeal cavity, oral cavity and nasal cavity – Tongue, teeth and lips By changing the vocal tract controlthat we produce different formants initiating – Consonants, vowels Any of several frequency regions of relatively great intensity in a sound spectrum, which together determine 3 the characteristic quality of the sound. Physical requirements for language (vocal) Vocal tracts in chimps and most other animals are not well suited to producing a wide variety of formants thusreducedabilitytolanguage – Human: lower larynx & longer oral cavity – Human: tongue can move more flexibly (than in chimpanzees) More developed vocal tract might lead to language? Or, having a brain that can control articulation (rapid movements of the lips, tongue palate) could lead to language development? Mo 4 Into the brain... 5 Audition: Tonotopic organization lotofthenucleileadthere 6 Audition: Tonotopic organization HG-Heschl’s gyrus HS-Heschl’s sulcus STG-Sup Temp Gyrus attending haw and 7 11.1 Anatomy of Language motorcortex in netting age tapis feasting Primarily L hemisphere Also: superior temporal sulcus & medial temporal gyrus Regions around sylvian fissure form “language processing network” 8 11.1 Genetic foundation for language? FOXP2 gene and the KE family – Deficit in sequencing articulation patterns Problems with pronunciation, syntax and grammar, repeating – Reduced volume of caudate nucleus, M1/S1, cerebellum and IFG (Broca’s) – Found a mutation in FOX-P2 gene Regulates other genes during Also linked to Autism development/learning 9 11.1 Genetic foundation for language? FOXP2 gene – Mice w/ human variant Greater synaptic plasticity in cortico-basal ganglia circuits – Mice w/ KE family variant Less! – Network contributes to motor skill learning FOXP2 present in wide range of vertebrates – Potential unique changes in Neanderthals and modern humans linked to language development 10 11.1 Language deficits Patients w/ brain damage as a window on function – Aphasia: Deficits in language comprehension/production – Broca’s production – Wernicke’s comprehension – Conduction (rare) – Dysarthria Loss of control of articulatory muscles ability toexpress speethwillbeindeer – Apraxia Deficits in motor planning of articulations – Anomia Specific form of aphasia, deficit in object naming 11 11.1 Language deficits Broca’s aphasia akaanterioraphasia anterior or nonfluentaphasia – Anterior, nonfluent, expressive – Production: aggott Single utterence FACE BA44 Single syllables/words Short phrases BA45 Mostly lacks grammar Effortful (hard to prodc) – Comprehension: thenonlythemostbasicandoverlearned grammatiialformsareproduced Syntax deficits (only understand simple statements) Patient interview 12 11.1 Language deficits Wernicke’s aphasia aka posterioraphasia posterior or receptiveaphasia – Posterior, receptive, fluent Difficultyunderstandingspokenorwritten productionbutcan'tunderstand – Production: languageYmelines whattheysayisoftennonsensical Intact (“fluent”) Most not meaningful – Comprehension: Severe deficit in understanding – Oral and written language – May not understand at all Patient interview 13 11.1 Language deficits Prototypical Broca’s/Wernicke’s? – A spectrum depending on extent and specific location of damage Other locations? – Broca’s L usually on aspectrumdependingwhenthedamageis come May require damage to deeper regions to affect production (basal ganglia?) – Wernicke’s comprehensiondeficits to swellingordamage tissuessurroundingregions rDamageinthat.gg Wernicke’s area andffsurrounding cortex of posterior TL hdsophfqednto Cortical damage or disconnection damage? 14 11.1 Wernicke–Lichtheim Model Classical model – Deficits characterized along the pathway from sound input to speech output involvingtheinteronnectionofdifferenttheybrainregionsand adamageof thisnetworkwouldresultinthe – **Not completely consistent with neuroanatomydithrent propose “conceptual information” formofaphasia X ifthoseconnectiondamage betweenthose regions theconnectivity disconnectionwhichaffect No evidence for theorized conceptual region Oversimplification Very important for the consideration of connectivity Poor speech repetition 15 11.1 Why Broca’s and Wernicke’s? Middle cerebral artery perfusion MCAP – MCA = most common stroke site closetobroca'sandWernickearea thuswhymoststrokeleadtoaphfsiaa.mu 16 A bit about language... 17 11.2 Components of language Phonolgy – specific sounds of a language and rules for how they make words – Phoneme – smallest sound unit, depends on language (“ba”, “pa”) Phonetics – how phonemes are produced in specific words Morphene – smallest meaningful unit in a language (‘un’‘happy’; ‘de’‘frost’‘er’) Syntax – the way words are organized into (grammatical) sentences Grammar – structural rules that govern the language 18 11.2 Components of language Lexical (word) representation in the brain The “mental lexicon” mappingoftheword as representation in thebrain – How is information about words represented in the brain? Semantic (meaning), syntactic (how to combine), details (spelling and sound) Ilikepronunciation Required for language comprehension or production – Lexical access (what word forms fit sound patterns?) – Lexical selection (select specific representation) – Lexical integration (in context of phrase and/or sentence) 19 11.2 Model of the mental lexicon Conceptual representation – Nodes and connections, organized? withother concepttheyarerelatedto fruits 20 11.2 Model of the mental lexicon Behavioural study to map the network of the mental lexicon – Reaction time to word/non – Can be combined with word priming Probes …? Participantsarefasterandmoreaccurate atmakingthelexitaldecisionfora realworld targetwhenitisprecedeby asemantially relatedprime https://www.psytoolkit.org/experim 21 ent-library/ldt.html 11.2 Neural Substrate (Lexicon) How can we determine how words are represented in the brain? – Words have meaning… Lwhichmeanthereis someorganization 22 Huth et al., 2016 11.2 Neural Substrate (Lexicon) Semantic (meaning) maps from fMRI story listening showingwhichword isassociated somewhatlocalizeand somewhatrandom withwhich regions whichmeans 23 Huth et al., 2016 Practical https://gallantlab.org/viewer-huth-2016/ 1.Read through all items on the top right 2.Get an overview of the regions that are semantically selective L somewhat similar inboth hemispheres Is it all regions? L regions are set in up thesameway Are some missing? What can you notice about this? 3.What, if any, implications could this have for memory? whenbuildingthemeaningofthestory itiswithwordweknewbefore thusmemory 24 11.3 Understanding speech Hierarchical processing tospeech transition fromsound – Multiple parallel paths – Gradients of function spectrumfrom tolow high Double-sided arrows? means isinfoisnot justflowingoneway feedback goingon 25  Whithneuralcircuitsandsystemsupport isimportant tounderstand speech 11.3 Understanding speech Hierarchical processing keyorganizationalaspectofthehumancorticalauditorysystem Heschl's gyrus – HG: sound (not lang spec) – HG→ post STS: Illinfferception speech sounds Cho Sts auditoryassociationcortex – Frontal regions: speech comprehension – Post ITL: access/integrate semantics AswemoveawayfromHGthebrainbecomelesssensitive tochangesin nonspeechbutmoretospeechsound 26 11.3 Understanding speech Connectome lesion mapping Stroke survivors w/ language deficits Lesion overlap Affected regions 27 Bonilha et al., 2017 11.3 Understanding speech ThestructuresurroundingtheSylvianregions Perisylvian language system (spoken language comprehension) Friederichi, A Thenpathwayareimportantto Indirect to FL – 2 ventral pathways word comprehend lobe temporal Post TL→ant TL / IFG frontal inferior gyrus – Word comprehension rimpoforspeechpreparation – 2 dorsal pathways Post TL→IFG akafrontallobe – Preparation for production area44 Brocus BA44→post STG temporal ALL superior gyrus arrows should be – Syntax processing considered double-sided 28 Language processing model summary M1 dPMC dlPFC vlPFC mappingsoundto vPMC meaning MTG Dorsal pathway: sensory to motor; sounds to actions (phonemes, production); syntax (rules of sentence structure) Ventral pathway: sound to meaning; sounds to object (words, grammar) 29  fordetermining thepropersenseorgrammaticalform Contextualrepresentation crucial messagerepresentationcan ofaword withoutsensory analysisno takeplace The3modelstoexplainwordcomprehension modularmodelhigherlevel rep cannotinfluencelowerlevelupandthereforethe flowisstrictlydatadrivenor Interaction model a ftp.lftintocanparticipate inwordrecognition likecontextcanhaveitsinfluenceevenbeforesensoryinfo isavailable Hybridmodelbasedonthelexinalaccessis autonomousandnotinfluenced byhigher levelinto butlexicalselectioncanbe influence bysensoryandhigherlevelcontextual information