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

Grodzinsky, Yosef (2000) The neurology of syntax: Language use without Broca's area.

Short Abstract:

A new view of the functional role of 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 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 - e.g., 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 together 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, nonetheless, are distinct from other cognitive skills, and 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.

Long Abstract:

A new view of the functional role of 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 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 - e.g., 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 together 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, nonetheless, are distinct from other cognitive skills, and 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.

Keywords:	agrammatism, aphasia, Broca's area, cerebral localization, dyscalculia, functional neuroanatomy, grammatical transformation, modularity, neuroimaging, syntax, trace-deletion.
Subjects:	Psychology: Applied Cognitive Psychology Linguistics: Syntax Neuroscience: Neuroanatomy Neuroscience: Neurolinguistics Neuroscience: Neural Modelling
ID code:	bbs00000551
Deposited by:	Yosef Grodzinsky on 02 May 2001