Towards a Neurobiology of Language Chairperson Steven L. Small (small@uci.edu) Departments of Neurology, Neurobiology & Behavior, and Cognitive Sciences University of California, Irvine, Irvine, California USA Speakers Ferdinand Binkofski (fbinkofski@ukaachen.de) Department of Neurology Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen, Aachen, Germany Steven L. Small (small@uci.edu) Departments of Neurology, Neurobiology & Behavior, and Cognitive Sciences University of California, Irvine, Irvine, California USA Uri Hasson (uhasson@gmail.com) Center for Mind/Brain Sciences (CIMeC) and Department of Psychology and Cognitive Science University of Trento, Mattarello (TN), Italy Jeremy Skipper (jskipper@lab-lab.org) Department of Experimental Psychology, Institute for Multimodal Communication University College London, London, England Mikkel Wallentin (mikkel@cfin.dk) Center of Functionally Integrative Neuroscience Aarhus University Hospital, Aarhus, Denmark The advent and/or improvement of high resolution brain Dorsal and ventral processing streams in the imaging methods over the past two decades – both spatial and temporal – has led to the emergence of an anatomically and human brain physiologically robust human neuroscience. In no area has this been more evident than in the study of human language. A Ferdinand Binkofski recent congress on the Neurobiology of Language attracted over 500 participants. Many – but not all – researchers in this field take the view that language processing in the brain is The distinction between dorsal and ventral processing implemented by many interacting sensory, motor, and streams has been elaborated substantially in recent years, conceptual networks that are not specific to language, but spurred by two developments: (1) First is a more detailed evolved to support many critical features of human cognition, description of the multiple neural circuits connecting the including contextual expectation, statistical inference, sequence frontal, temporal, and parietal cortices; and (2) Second are a processing, error detection and correction, and related computational basics. The neural systems that underlie these number of behavioral observations that the classic "two computations appear to incorporate a large number of anterior- visual systems" hypothesis needs refinement to posterior brain connections along dorsal and ventral “streams”. accommodate additional assumptions. The notion that there Although these streams each include many individual is a single dorsal stream that is specialized for "where" or connections, and contribute to many different functions, some "how" actions and a single ventral stream for "what" gross functional generalities can be articulated. In this Symposium, we introduce the anatomy of these streams, and knowledge cannot account for two prominent disorders of then describe several models and/or cognitive functions that action, limb apraxia and optic ataxia, that represent a support language processing in dorsal and ventral brain double dissociation in terms of the types of actions that are networks. preserved and impaired. A growing body of evidence suggests that there are at least two distinct dorsal routes in 2 the human brain, which we characterize as the "Grasp" and Statistical regularities in input: The basis of "Use" systems. Both of these may be differentiated from the neural encodings for language ventral route in terms of neuroanatomic localization, representational specificity, and time course of information Uri Hasson processing. In this talk, we discuss the anatomy and physiology of the dorsal and ventral streams for vision and The capacity to code for statistical features of language is action, and relate them to the analogous streams for thought to enable language learning, assist online word audition, speech, and language. segmentation, and form a basis for prediction of subsequent speech input. How does the brain code for the statistical structure of the language stream? I will present Neurobiological roots of language in primate recent neuroimaging data addressing this question, and audition: Common computational properties focus on three issues: a) Is there a domain general system sensitive to structure in both language-like and non- Steven L. Small language like inputs? b) Are there separate systems sensitive to different types of statistical information, e.g., Neurobiologically plausible models of human brain marginal frequency vs. transition probability? and c) Are function are typically based on detailed animal models. different forms of statistical learning engaged depending However, while the applicability of this modeling strategy on whether the language tokens are novel or familiar? The is widely accepted for domains such as vision or audition, answers to these questions (no, yes, and yes) suggest the its transferability to human language is considerably more existence of distributed, domain-specific systems for controversial. The reason for this perspective – particularly encoding statistical structure, with separate brain systems at the level of sentences and above – relates to complex coding for different statistical aspects of the stimulus. computational properties of human grammars and their (Research supported by ERC starting grant NeuroInt) purported specificity to our species. It is generally accepted that human speech and language processing is supported by a cortical dorsal-ventral streams architecture that shares Context is all: There is no fixed organization of many anatomical characteristics with the extended auditory language and the brain system of nonhuman primates. A postero-dorsal stream connects AC to the posterior and dorsal part of inferior Jeremy Skipper frontal cortex (IFC) (Brodmann area [BA] 44) via posterior superior temporal (pST) cortex, inferior parietal lobule Is there a ‘center of speech’ in the brain? It is generally (IPL), and premotor cortex (PMC, whereas an antero- (though perhaps implicitly) assumed that there is. In ventral stream traverses anterior superior temporal cortex contrast, I argue that there is no core, i.e., fixed region, set (aST) to terminate in more anterior and ventral parts of the of regions, or (dual) "streams" supporting the inferior frontal gyrus (BA 45). Dual–stream models of organization of language and the brain. I suggest that the sentence processing typically assume that the neural illusion that there is some core is created by: 1) the wiring circuitry of nonhuman primates is insufficient to support of the brain, 2) the methods and statistics used in sentence comprehension because of a fundamental neuroimaging and 3) the fact that we have not observed difference in its computational architecture that is not the brain during natural language use. Supporting this simply a matter of degree. They thus posit uniquely human argument, I show that the same word can have a very additions to this circuitry in the dorsal stream, which are different whole brain organization as a function of the assumed to have evolved late from a phylogenetic type of context that accompanies that word. Context perspective and to mature late from an ontogenetic includes both that which is present (e.g., observable perspective. In this talk, we suggest that the nonhuman speech associated gestures) and that which has been primate dorsal and ventral auditory streams have the previously experienced (e.g., music, lip movements, and necessary mechanistic components to perform sentence and written text repeatedly encountered in the past). I also discourse processing, even though the system lacks the show that, even in brain regions where activity might be necessary quantitative scale to support language. expected to be comparable for a word heard in different (Research supported by the National Institutes of Health of the contexts, e.g., auditory cortex, it is not. I argue from these USA) results that, rather than being organized around linguistic information per se, language and the brain is organized around context. This is because context is necessary for speech perception and language comprehension to occur. Because the context associated with natural language use 3 is ever changing, so to will the many brain networks that comprise the organization of language and the brain be dynamic. Context predicts word order processing in Broca's region Mikkel Wallentin While famous for its role in language processing, the actual function of the left inferior frontal gyrus (L-IFG) is still highly disputed. In terms of dual stream models, it has recently been argued to be part of the dorsal stream for speech, whereas it has also traditionally been considered as part of the extended ventral visual stream. A number of language processing studies have linked the region to the processing of syntactic structure. Still, there is little agreement when it comes to defining why linguistic structures differ in their effects on the L-IFG. In a number of languages, the processing of object-initial sentences affects the L-IFG more than the processing of subject-initial ones, but frequency and distribution differences may act as confounding variables. Syntactically complex structures (like the object-initial construction in Danish) are often less frequent and only viable in certain contexts. With this confound in mind, the L-IFG activation may be sensitive to other variables than a syntax manipulation on its own. This talk investigates the effect of a pragmatically appropriate context on the processing of subject-initial and object-initial clauses with the IFG. We find that Danish object-initial clauses yield a higher BOLD response in L-IFG, but we also find an interaction between appropriateness of context and word order. Given an appropriate context, the L-IFG activation drops remarkably for object-initial clauses. This interaction overlaps with traditional syntax areas in the IFG. Further, an acceptability study shows that, given appropriate contexts, object-initial clauses are considered more appropriate than subject-initial clauses. The increased L-IFG activation for processing object-initial clauses without a supportive context may be interpreted as reflecting either reinterpretation or the recipients' failure to correctly predict word order from contextual cues. These findings are discussed in relation to the dual stream models. 4