Language and the Brain, 1924-2014
Developments in Neurology/ Neuroscience, Linguistics, and Psycholinguistics
Lise Menn, University of Colorado Ma hew Goldrick, Northwestern University 1924: Disciplines isolated, language data only via M.D.’s descriptions
• Neurology: Best available analogy for brain function was telephone switchboard. Understood that information is relayed from some parts of brain to other parts, but no clue about nature of the sources of that information. • Linguistics: not in the picture – no corpora! Recording devices clumsy, used by ethnomusicologists but by few other scientists (c.f. Bloomfield, via Keating; also what Barbara Partee said about semantics). • Psychology: Stimulus-response behaviorism beginning to dominate (cf. Bever!); introspection discredited (and not much help anyway)
3 jan 2014 Menn & Goldrick, LSA 1924-2014 2 Neurology: Trying to link brain damage to behavior change • Time lag: brain injuries mapped at autopsy had to be compared to descriptions of language behavior, possibly from years earlier. – during that time, the brain damage could have partly healed, or gotten worse • The only in vivo evidence for loca on of brain damage came from figuring the trajectories of penetra ng brain wounds • or from no ng damage to sensory and motor abili es (the motor and sensory cortex had been fairly well mapped by 1924). 3 jan 2014 Menn & Goldrick, LSA 1924-2014 3 The most comprehensible theorists were the ‘localizationists’ • The localizationists, also called ‘connectionists’, envisioned the parts of the brain that they mapped out as a collection of ‘centers’ containing motor or sensory images, connected by bundles of nerve fibers which transmitted information from one to another (telephone switch-board model) and eventually to muscles. • Severing specific connections (✖ ), e.g. between visual input and visual memory for letters, could explain puzzles like patients who can write but not read (‘alexia without agraphia’). But it drastically oversimplified many cases.
B = Begriff ‘concept’ (large interconnected set of memory images) M = Motor memory ✖ ✖ images for ar cula on m = motor output pathway for speech A = Auditory sensory images for word sounds a = pathway for auditory informa on slide based on Graves (2009), ‘The Legacy of the Wernicke-Lichtheim Model’ 3 jan 2014 Menn & Goldrick, LSA 1924-2014 4 Complicated (but not rare!) cases Head (1926:179), clinical example • Young ofcer, blunt trauma, left parieto-occipital region, “perpetually at a loss for names”. Asked to name the color of a black patch: …people who are dead…the other people who are not dead, they have this color. “Choice of colours to oral command [was] slow.” – Explaining slowness of comprehension in terms of some kind of disconnection requires a lot of ad hoc apparatus! • Pointed to matchbox on seeing printed word MATCHES, but unable to get meaning from WATCH until he spotted a wall clock. When I look at that big one (clock) that helps me…If you say it to me, I see it at once; if you show it to me like that (printed), I have to think, I don’t get the picture easily. – Information from seeing a printed word and seeing an object it can refer to - or a semantically/visually related object - have to combine for this patient to understand the word he is looking at. Localizationist brain model has no way to combine diferent types of information.
3 jan 2014 Menn & Goldrick, LSA 1924-2014 5 Many localizationists failed to apply the basic logic of troubleshooting complex systems
If you have an amplifier not giving you normal sound and you see a loosely connected component, you can guess that that component is involved in delivering the sound. You don’t assume, without further evidence, that it’s the source of the sound. But many localizationists did the equivalent: if a disability was associated with a lesion (injury) in a particular area, they concluded that that area was responsible for that ability - e.g. ‘Exner’s center’, supposed to be ‘the location’ for reading.
3 jan 2014 Menn & Goldrick, LSA 1924-2014 6 Some localizationists got the logic right: Head (1926) expounds Arnold Pick: “When … he states that syntactical deficits [agrammatism] are caused by a lesion of the left temporal lobe, he does not mean that “grammatism”, or the correct use of syntax, is centred within this region. He implies solely that a lesion, situated in this part of the brain, can disturb the processes of normal speech in such a way that the phenomena of agrammatism become apparent.”
But cautious, complex statements like this don’t make good sound bites. The people who made them were overshadowed by those who said confidently “Here is grammar, there is speech, over there is reading.” 3 jan 2014 Menn & Goldrick, LSA 1924-2014 7 No corpora, no linguistics • Apparently, no recordings were ✖ made of aphasic speakers. Working with aphasic speakers is not like field work with normal speakers. Aphasic speakers have much less control, can’t voluntarily ‘say it again’. Transcription on the fly is difcult, especially with ‘fluent’ aphasic speakers like this person, VIDEO HERE who were described by doctors as
having ‘normal syntax’. § “Normal” label was probably cued by use of formulaic expressions like the ones in this clip: “Pretty good, actually…” “Yeah, I guess…”
3 jan 2014 Menn & Goldrick, LSA 1924-2014 8 Recording Speech Makes Linguistic Analysis Possible
Stark & Dressler (1990) in Menn & Obler (eds.) Agrammatic Aphasia:
Spoken words with Und es rinn-t⎦ der Hahn ⎣über morpheme boundary markers (- ⎦ ⎣) Transla on with And it flow-PRES,3SG⎦ the faucet ⎣over-SEP PREF labeled gramma cal morphemes Colloquial equivalent ‘And the faucet is overflowing’
Target picture: water is running from faucet, overflowing a sink. “Blend” of two inten ons: The faucet is running + The water is overflowing
3 jan 2014 Menn & Goldrick, LSA 1924-2014 9 Measurement Makes Linguistic Analysis Possible • Reveals sub-perceptual variation—in principle inaccessible to transcription
• Building on techniques developed for medical imaging (e.g., cardiac), real-time MRI allows imaging of global configurations of vocal tract (Narayaran et al. 2004). – Example movie with articulator tracings.
• Hagedorn et al. (2012): Real-time MRI of apraxic repetition reveal covert gestures not visible in acoustic signal – Frame from /f/ in “federation,” heard and transcribed as [r]. – Imaging reveals labial closure is present, but is obscured, hard to hear because of the simultaneously produced /r/ gesture.
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Token 1 Token 2 Figure 5: Two productions by apraxic subject of initial Figure 3: Acoustic waveform (top) and time-aligned fricative in lexical item “federation.” Left: target estimated constriction functions (labial, coronal, dorsal) production; Right: labial constriction co-produced with in second /kɒp-tɒp/ repetition trial: apraxic speaker. intrusive lingual gesture corresponding to tongue Labial and tongue tip gestures coordinated in-phase posture observed during [ɹ] production later in same (synchronously) (arrows). Dorsal gestures are missing at word. Labialization not discernible in acoustic signal of expected times (boxes). second token.
I can type (TT) bow know Words exhibiting multiple initiations included those starting with /w/ (100% of /w/ tokens), /dʒ/ (50% of tokens), /s/ (16%), /m/ (20%), /l/ (20%), /t/ (50%), and /d/ (50%). It is noteworthy that I can type (TT) bow know 0.5 1 1.5 2 2.5 3 3.5 4 4.5 the majority of these segments that were problematic for the Labial p b subject require more than one vocal tract gesture. This suggests Degree I can type (TT) bow know oU oU 0.5 1 1.5 2 2.5 3 3.5 4 4.5 that the added complexity of gestural coordination required for Coronal nt the production of multi-gestural segments might present I can type (TT) bow know n Constriction 0.5 1 1.5 2 2.5 3 3.5 4 4.5 Dorsal additional challenges in planning, with the result that they k exhibit false starts, or perhaps explicit articulation as part of the 0.5 1 1.5 2 2.5 3 3.5 4 4.5 planning process. In many cases, the repeated initiation gestures Time (sec) are covert, being articulated without any phonation, and could not, therefore, be captured by acoustic analysis or adequately Figure 4: Audio signal (top) and time-aligned labial, represented in standard phonetic transcription. coronal & dorsal constriction functions reveal covert In Figure 6, a silent tongue tip gesture (arrow) can be seen to tongue tip intrusion during labial closure for /b/ in precede full (and audible) production of the coronal-initial word apraxic utterance “I can type ‘bow know’ five times.” no [noʊw] in the utterance “I can type ‘bone no’ five times”. Under acoustic analysis, the duration of the covert gesture might Some of the individual words produced by the subject also reveal be interpreted as a pause, however using rtMRI, we find that a evidence of gesture intrusions. Acoustic analysis of one of the complete tongue tip gesture is present. subject’s responses to the stimulus item “federation” suggests a form which might be represented in close transcription as Evidence for covert gestural rehearsal is also shown in [ɹɛd&ɹeɪʃ&n]. Articulatory analysis of the same utterance using Figure 7, where three silent tongue tip gestures can be observed rtMRI provided additional insights: the segment transcribed as in the interval before the vocalized production of the coronal [ɹ] was found not to arise from simple “anticipatory substitution” stop which initiates successful production of the complete lexical (segment [ɹ] replaces segment [f]); rather, the initial labial item temperatures. gesture of target /f/ was observed to be synchronously produced with an anticipatory lingual intrusion gesture for [ɹ]. Target and erroneous productions of the initial portion of the word “federation” are compared in Figure 5.
3.1 Multiple Initiation Gestures in Spontaneous Speech Consistent with earlier findings [5], multiple initiation gestures by this subject were found to be more frequent in spontaneous speech than in imitated speech. Segments used word-initially by the apraxic subject in spontaneous speech included /t/, /d/, /g/, /k/, /b/, /dʒ/, /w/, /f/, /s/, /n/, /m/, /l/, /ð/, and /h/. Tokens exhibiting multiple initiation gestures are defined as those in Figure 6: Covert tongue tip gesture during first (silent) which a visible articulatory gesture occurs at least once before attempt at producing coronal-initial word ‘no’ in the complete production of the word. utterance “I can type ‘bone no’ five times.”
‘The Cognitive Revolution’: Psycholinguistics
• Basic elements of mind/brain are complex computational processes manipulating structured mental representations. • Behavior reflects the coordinated interaction of these processes. Ø Complexity of component processes and interactions moved far beyond simple stimulus-response theories.
• Integrated into study of language disorders – Marshall and Newcombe (1966) – Semantic errors (CANARY à“parrot”) reflect cognitive consequence of brain injury: Disrupted access to stored “lexical entries,” specifying syntactic, semantic categories and features (explicitly referencing proposal of Katz & Fodor, 1963) Freda Newcombe, 1925-2001 3 jan 2014 Menn & Goldrick, LSA 1924-2014 11 Complex Computation: Parallel Activation • Complex computational structure allows us to understand complex behavioral phenomena. • Parallel activation: At many (all?) stages of processing, in perception and production, computation involves simultaneous activation of multiple linguistic representations.
• Parallel activation of alternative formulations of message provides an account of syntactic blends – Aphasia example from above: The faucet is overflowing § The faucet is running + The water is overflowing – Normal speaker’s speech error: § The road to Chicago is straight as a pancake § straight as an arrow + flat as a pancake (Cutting & Bock, 1997) – Constrained by complex internal structure of idioms, collocations (≈ frequent word sequences; Menn & Dufeld, 2013) 3 jan 2014 Menn & Goldrick, LSA 1924-2014 12 From Static Pathology to the Living Brain
• Quantitative shift since 1924: Imaging technology allows a precise view of brain structure – In both pathological and healthy brains. • Qualitative shift: We can now observe the healthy brain in action. 4953 (1993) 90 USA Sci. Acad. Natl. Proc. al. et McCarthy Neurobiology: – Electrical activity of ensembles of neurons – Metabolic activity correlated with neuronal processing
Earliest First language- human related fMRI: Heat EEGs: map of increase in Patient blood flow across of Hans tasks includes Berger, Broca’s area 1924 (McCarthy et al. 1993)
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• Fedorenko and Thompson- Schill (in press, TiCS)
• Comparison of language- related tasks to various “non-linguistic” baselines reveals increased metabolic activity in a widely distributed network —not just ‘classical’ (printed word processing) language areas
3 jan 2014 Menn & Goldrick, LSA 1924-2014 14 Coordinated Interaction Between Brain Areas • Early neuroimaging work: Functional localization – Which brain regions show heightened metabolic activity when a certain cognitive function is (strongly) engaged? • More recent work: Functional connectivity – What are interdependencies in metabolic or electrical activity across brain regions?
• Interdependencies are context-
dependent intraparietal sulcus – Ex: Shifting task from judging inferior spelling vs. sound similarity of frontal gyrus written words shifts interdependence between lateral temporal fusiform brain regions. cortex gyrus – Red: stronger when judging Bitan et al., spelling similarity 2005, Fig. 5 3 jan 2014 Menn & Goldrick, LSA 1924-2014 15 From nodes to networks
• These technological/methodological advances have fueled nascent theoretical perspectives (Keating, Aronof) Fedorenko and Thompson-Schill (in press) • Long-standing debate: What is the function of a brain region, domain-general or domain-specific? • Proposal: Re-focus on dynamic network structure – How are domain-specific vs. -general regions coordinated to accomplisha. currentt=1 processing goals?t=2 b.
Ex: Domain-general nodes (multi-colored) coordinate with two distinct domain- specific networks (green, pink nodes) depending on taskc. t=1 t=2 d.
3 jan 2014 Menn & Goldrick, LSA 1924-2014 16 Language and the Brain, 1924-2014 Linguistics: From Words to Multilayered Structures Now using recorded observations to bring the conceptual structure of linguistics to bear on neurological data
Psycholinguistics: From Relaying Stored Auditory Images to Computation Now using insights of the cognitive revolution for analysis of language behavior
Neurology/Neuroscience: From Autopsy to fMRI Now using methods that provide a picture of the dynamic, living brain
Challenge: Need to create new theoretical frameworks to handle the torrent of data about activity in the brain and the cognitive computations that underlie language use.
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