Yosef Grodzinsky

The neurology of syntax: Language use without Broca's area

A new view of the functional role of the left anterior cortex in language use is proposed. The experimental record indicates that most human linguistic abilities are not localized in this region. In particular, most of syntax (long thought to be there) is not located in Brocas area and its vicinity (operculum, insula, and subjacent white matter). This cerebral region, implicated in Brocas aphasia, does have a role in syntactic processing, but a highly specific one: It is the neural home to receptive mechanisms involved in the computation of the relation between transformationally moved phrasal constituents and their extraction sites (in line with the Trace-Deletion Hypothesis). It is also involved in the construction of higher parts of the syntactic tree in speech production. By contrast, basic combinatorial capacities necessary for language processing--for example, structure-building operations, lexical insertion--are not supported by the neural tissue of this cerebral region, nor is lexical or combinatorial semantics. The dense body of empirical evidence supporting this restrictive view comes mainly from several angles on lesion studies of syntax in agrammatic Brocas aphasia. Five empirical arguments are presented: experiments in sentence comprehension, cross-linguistic considerations (where aphasia findings from several language types are pooled and scrutinized comparatively), grammaticality and plausibility judgments, real-time processing of complex sentences, and rehabilitation. Also discussed are recent results from functional neuroimaging and from structured observations on speech production of Brocas aphasics. Syntactic abilities are nonetheless distinct from other cognitive skills and are represented entirely and exclusively in the left cerebral hemisphere. Although more widespread in the left hemisphere than previously thought, they are clearly distinct from other human combinatorial and intellectual abilities. The neurological record (based on functional imaging, split-brain and right-hemisphere-damaged patients, as well as patients suffering from a breakdown of mathematical skills) indicates that language is a distinct, modularly organized neurological entity. Combinatorial aspects of the language faculty reside in the human left cerebral hemisphere, but only the transformational component (or algorithms that implement it in use) is located in and around Brocas area.

Language deficits and the theory of syntax

A new structural account of agrammatism is proposed, which analyzes the deficit in terms of one current theory of syntax. First, the motivation for accounts of this kind is given. Then, a variety of experimental findings from sentence comprehension in agrammatism are examined and accounted for in a unified way. It is shown that a minimal change in the syntactic model (achieved by imposing a special condition on a construct called trace), results in a model which accounts for all the data at hand. A number of possible objections to this proposal is then examined, and reasons are given to dismiss these objections. Also, it is shown that this proposal is preferable to other structural accounts which have been recently proposed. Finally, the empirical consequences of this account are discussed, with a special emphasis on the implications for models of language processing.

Tense and Agreement in Agrammatic Production: Pruning the Syntactic Tree

This paper discusses the description of agrammatic production focusing on the verbal inflectional morphology. Agrammatism in Hebrew is investigated through an experiment with a patient who displays a highly selective impairment: agreement inflection is completely intact, but tense inflection, use of copula, and embedded structures are severely impaired. A retrospective examination of the literature shows that our findings are corroborated by others. A selective account of the agrammatic production deficiency is proposed, according to which only a subclass of the functional syntactic categories is impaired in this syndrome. The consequence of this deficit is the pruning of the syntactic phrase marker of agrammatic patients, which impairs performance from the impaired node and higher. These findings also bear upon central issues in linguistic theories, particularly that of Pollock (1989), regarding split inflection.

Neuroimaging of syntax and syntactic processing

Recent results challenge and refine the prevailing view of the way language is represented in the human brain. Syntactic knowledge and processing mechanisms that implement syntax in use are mapped onto neural tissue in experiments that harness both syntactic concepts and imaging technologies to the study of brain mechanisms in healthy and impaired populations. In the emerging picture, syntax is neurologically segregated, and its component parts are housed in several distinct cerebral loci that extend beyond the traditional ones - Brocas and Wernickes regions in the left hemisphere. In particular, the new brain map for syntax implicates portions of the right cerebral hemisphere.

The Neural Reality of Syntactic Transformations Evidence From Functional Magnetic Resonance Imaging

The functional anatomy of syntactic transformations, a major computational operation invoked in sentence processing, was identified through a functional magnetic resonance imaging investigation. A grammaticality judgment task was used, presented through a novel hidden-blocks design. Subjects listened to transformational and non-transformational sentences in which a host of other complexity generators (number of words, prepositions, embeddings, etc.) were kept constant. A series of analyses revealed that the neural processing of transformations is localizable, evoking a highly lateralized and localized activation in the left inferior frontal gyrus (Brocas region) and bilateral activation in the posterior superior temporal sulcus. The pattern of activation associated with transformational analysis was distinct from the one observed in neighboring regions, and anatomically separable from the effects of verb complexity, which yielded significant activation in the left posterior superior temporal sulcus. Taken together with neuropsychological evidence, these results uncover the neural reality of syntactic transformations.

The battle for Broca’s region

The intense effort to characterize Brocas region has produced many views on its anatomy and function. Here, we present the leading approaches and consider ways to adjudicate among them empirically. Anatomically, we focus on the cytoarchitecture of Brodmann areas 44 and 45, which constitute Brocas region. Functionally, we discuss four views: action perception, working memory, syntactic complexity and syntactic movement. We compare these views, reflect on how they can be distinguished experimentally and review relevant aphasia and functional magnetic resonance imaging (fMRI) studies. Although no single hypothesis accounts for all of the data, the role of Brocas region in language comprehension is best explained by the syntactic movement account. This conclusion opens the door for an attempt to define general principles for the neural representation of linguistic knowledge.

The syntactic characterization of agrammatism

Abstract A new characterization of agrammatism is suggested, based on new data from Hebrew speaking agrammatic aphasics, and a reexamination of data from Russian and Italian. This characterization is formed in relation to linguistic levels of representation. First, the description of agrammatism as omission of closed-class items is challenged on the basis of the data, and a new description is suggested—viewing agrammatism as mis-selection of items + default: in English the default procedure may always be used, but in the other languages discussed, the patient is forced, for structural reasons, to unconscious guessing that results, in many instances, in syntactically aberrant sentences in which each lexical item is well formed. Second, after discussing issues concerning the proper relation between linguistic theories and processing models, a condition on a syntactic level (S-structure) in linguistic theory (Chomsky, 1981) is proposed, to account for agrammatic data from all the languages considered. It is then shown that agrammatic performance in a variety of tasks (including comprehension) is explained naturally as a consequence of this condition. Finally, several related processing issues are discussed. In particular, the relationship between the proposed structural account and the model offered by Bradley et al. (1980).

Neural correlates of syntactic movement: converging evidence from two fMRI experiments

This paper studies neural processes of sentence comprehension, focusing on a specific syntactic operation-syntactic movement. We describe two fMRI experiments that manipulate this particular syntactic component. The sentences in each of the experiments are different, yet the structural contrast in both is syntactically identical, comparing movement and no-movement sentences. Two distinct Hebrew constructions, topicalization and wh-questions, were presented in an auditory comprehension task and compared to carefully matched baseline sentences. We show that both contrasts, presented in an auditory comprehension task, yield comparable activations in a consistent set of brain regions, including left inferior frontal gyrus (IFG), left ventral precentral sulcus (vPCS), and bilateral posterior superior temporal sulcus (pSTS). Furthermore, we show that these regions are not sensitive to two other syntactic contrasts. The results, considered in the context of previous imaging and lesion studies, suggest that the processing of syntactic movement involves a consistent set of brain regions, regardless of the superficial properties of the sentences at issue, and irrespective of task.

The Critical Role of Group Studies in Neuropsychology: Comprehension Regularities in Broca's Aphasia

We reexamine the empirical record of the comprehension abilities of Brocas aphasic patients. We establish clear, commonly accepted, selection criteria and obtain a pool of results. We then subject these results to a detailed statistical analysis and show that these patients comprehend certain canonical sentences (actives, subject relatives, and clefts with agentive predicates) at above-chance levels, whereas comprehension of sentences that contain deviations from canonicity (passives, object-gap relatives, and clefts) is distinct and is at chance. That the latter is the case, and patients indeed guess at such structures, we show by comparing the distribution of individual results in passive comprehension to that of a model for such guessing-an analogous series of tosses of an unbiased coin. The two distributions are virtually identical. We conclude that the groups performance is stable, and well-delineated, despite intersubject variation whose source is now identified. This means that certain comprehension tests may not always be used for the diagnosis of individual patients, but they do characterize the group. It also means that group studies are not just a valid option in neuropsychology; they are a must, since demonstrations like ours indiciate very clearly that single-case studies may be misleading. As we show, the findings from any one patient, without the context of a group, may give a distorted picture of the pathological reality. Our conclusions thus promote studies of groups of brain-damaged patients as a central tool for the investigation of brain/behavior relations.

Children's Passive: A View from the By -Phrase

This article argues that childrens difficulty with passive constructions is related to properties of the by-phrase. Specifically, we argue that children are in full control of all aspects of the passive construction except for the ability to transmit the external -role of the predicate to the by-phrase; we thus reject Borer and Wexlers (1987) claim regarding the maturation of A-chains. Our conclusion is dictated by the results of an experiment we conducted, and supported by data already present in the literature.