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

Abstract

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 Broca's area and its vicinity (operculum, insula, and subjacent white matter). This cerebral region, implicated in Broca's 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 Broca's 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 Broca's 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 Broca's area.

Spectral and temporal degradation of speech as a simulation of morphosyntactic deficits in English and German

“…They also fit with the general Ôsubject-firstÕ strategy that has been shown for such patients in English, German, Italian, and Dutch, as well as for normal subjects working under perceptual or attentional loads (Strube, 1996;Vos, Gunter, Kolk, & Mulder, 2001a;Vos, Gunter, Schriefers, & Friederici, 2001b). The specific result for German object clefts is especially interesting in light of a current controversy on the nature and causes of receptive agrammatism (Friederici & Gorrell, 1998;Grodzinsky, 2000). Based on results for English, it has been argued that aphasic patients (whose results we have simulated here) find it difficult to process non-canonical word order configurations.…”

Interactions of the hippocampal system and the prefrontal cortex in learning language-like rules

“…A morphological left-over-right asymmetry was found for BA44, but not for BA45 (Amunts et al, 1999). Broca's area was shown to be involved in syntactic processes in a number of neuropsychological studies, in particular in that patients with lesions including Broca's area clearly suffering from syntactic deficits (Grodzinski, 2000;Caplan and Waters, 1999). In addition, some recent brain imaging studies have demonstrated increased hemodynamic activity in Broca's area during the processing of syntactic aspects during language comprehension (Dapretto and Bookheimer, 1999;Embick et al, 2000;Friederici et al, 2000a;Just et al, 1996;Moro et al, 2001;Tettamanti et al, 2002).…”

Finding needles in haystacks: Symbolic resonance analysis of event-related potentials unveils different processing demands

“…The same is shown by the fact that the free accusative is not involved in processes of argument reassignment as in passive constructions, see (17). (17). *Der ganze Tag wurde von Anna repariert.…”

“…But our feeling that this interpretation is derived fast and effortlessly should not obscure the fact that much information processing has to be performed by our brains in order to achieve it. Accordingly, this central issue has led to many studies in both psycholinguistics (see [15], for an overview) as well as aphasiology (see [17], for an overview). In order to characterize this type of information more closely, we will consider a sentence such as (2), which can immediately be judged to be unacceptable in English.…”