[show abstract][hide abstract] ABSTRACT: The central question underlying this study revolves around how children process co-reference relationships-such as those evidenced by pronouns (him) and reflexives (himself)-and how a slowed rate of speech input may critically affect this process. Previous studies of child language processing have demonstrated that typical language developing (TLD) children as young as 4 years of age process co-reference relations in a manner similar to adults on-line. In contrast, off-line measures of pronoun comprehension suggest a developmental delay for pronouns (relative to reflexives). The present study examines dependency relations in TLD children (ages 5-13) and investigates how a slowed rate of speech input affects the unconscious (on-line) and conscious (off-line) parsing of these constructions. For the on-line investigations (using a cross-modal picture priming paradigm), results indicate that at a normal rate of speech TLD children demonstrate adult-like syntactic reflexes. At a slowed rate of speech the typical language developing children displayed a breakdown in automatic syntactic parsing (again, similar to the pattern seen in unimpaired adults). As demonstrated in the literature, our off-line investigations (sentence/picture matching task) revealed that these children performed much better on reflexives than on pronouns at a regular speech rate. However, at the slow speech rate, performance on pronouns was substantially improved, whereas performance on reflexives was not different than at the regular speech rate. We interpret these results in light of a distinction between fast automatic processes (relied upon for on-line processing in real time) and conscious reflective processes (relied upon for off-line processing), such that slowed speech input disrupts the former, yet improves the latter.
Journal of Psycholinguistic Research 05/2009; 38(3):285-304. · 0.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: Verbal working memory, that is, the temporary maintenance of linguistic information in an activated state, is typically assumed to rely on phonological representations. Recent evidence from behavioral, neuropsychological, and electrophysiological studies, however, suggests that conceptual-semantic representations may also be maintained in an activated state. We developed a new semantic working memory task that involves the maintenance of a novel conceptual combination. Functional magnetic resonance imaging data acquired during the maintenance of conceptual combinations, relative to an item recognition task without the possibility of conceptual combination, demonstrate increased activation in the posterior left middle and inferior temporal gyri (known to be involved in conceptual representations) and left inferior frontal gyrus (known to be involved in semantic control processes). We suggest that this temporo-frontal system supports maintenance of conceptual information in working memory, with the frontal regions controlling the sustained activation of heteromodal conceptual representations in the inferior temporal cortex.
Journal of Cognitive Neuroscience 01/2008; 19(12):2035-49. · 4.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: We report on three experiments that provide a real-time processing perspective on the poor comprehension of Broca's aphasic patients for non-canonically structured sentences. In the first experiment we presented sentences (via a Cross Modal Lexical Priming (CMLP) paradigm) to Broca's patients at a normal rate of speech. Unlike the pattern found with unimpaired control participants, we observed a general slowing of lexical activation and a concomitant delay in the formation of syntactic dependencies involving "moved" constituents and empty elements. Our second experiment presented these same sentences at a slower rate of speech. In this circumstance, Broca's patients formed syntactic dependencies as soon as they were structurally licensed (again, a different pattern from that demonstrated by the unimpaired control group). The third experiment used a sentence-picture matching paradigm to chart Broca's comprehension for non-canonically structured sentences (presented at both normal and slow rates). Here we observed significantly better scores in the slow rate condition. We discuss these findings in terms of the functional commitment of the left anterior cortical region implicated in Broca's aphasia and conclude that this region is crucially involved in the formation of syntactically-governed dependency relations, not because it supports knowledge of syntactic dependencies, but rather because it supports the real-time implementation of these specific representations by sustaining, at the least, a lexical activation rise-time parameter.
Brain and Language 01/2008; 107(3):203-19. · 3.39 Impact Factor
[show abstract][hide abstract] ABSTRACT: This experiment examined the time course of integration of modifier-noun (conceptual) combinations during auditory sentence comprehension using cross-modal lexical priming. The study revealed that during ongoing comprehension, there is initial activation of features of the noun prior to activation of (emergent) features of the entire conceptual combination. These results support compositionality in conceptual combination; that is, they indicate that features of the individual words constituting a conceptual combination are activated prior to combination of the words into a new concept.
[show abstract][hide abstract] ABSTRACT: Using functional magnetic resonance imaging (fMRI), this study directly examined an issue that bridges the potential language processing and multi-modal views of the role of Broca's area: the effects of task-demands in language comprehension studies. We presented syntactically simple and complex sentences for auditory comprehension under three different (differentially complex) task-demand conditions: passive listening, probe verification, and theme judgment. Contrary to many language imaging findings, we found that both simple and complex syntactic structures activated left inferior frontal cortex (L-IFC). Critically, we found activation in these frontal regions increased together with increased task-demands. Specifically, tasks that required greater manipulation and comparison of linguistic material recruited L-IFC more strongly; independent of syntactic structure complexity. We argue that much of the presumed syntactic effects previously found in sentence imaging studies of L-IFC may, among other things, reflect the tasks employed in these studies and that L-IFC is a region underlying mnemonic and other integrative functions, on which much language processing may rely.
[show abstract][hide abstract] ABSTRACT: This paper presents three studies which examine the susceptibility of sentence comprehension to intrusion by extra-sentential probe words in two on-line dual-task techniques commonly used to study sentence processing: the cross-modal lexical priming paradigm and the unimodal all-visual lexical priming paradigm. It provides both a general review and a direct empirical examination of the effects of task-demand in the on-line study of sentence comprehension. In all three studies, sentential materials were presented to participants together with a target probe word which constituted either a better or a worse continuation of the sentence at a point at which it was presented. Materials were identical for all three studies. The manner of presentation of the sentence materials was, however, manipulated; presentation was either visual, auditory (normal rate) or auditory (slow rate). The results demonstrate that a technique in which a visual target probe interrupts ongoing sentence processing (such as occurs in unimodal visual presentation and in very slow auditory sentence presentation) encourages the integration of the probe word into the on-going sentence. Thus, when using such 'sentence interrupting' techniques, additional care to equate probes is necessary. Importantly, however, the results provide strong evidence that the standard use of fluent cross-modality sentence investigation methods are immune from such external probe word intrusions into ongoing sentence processing and are thus accurately reflect underlying comprehension processes.
Journal of Psycholinguistic Research 06/2006; 35(3):215-31. · 0.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: Previous research has implicated a portion of the anterior temporal cortex in sentence-level processing. This region activates more to sentences than to word-lists, sentences in an unfamiliar language, and environmental sound sequences. The current study sought to identify the relative contributions of syntactic and prosodic processing to anterior temporal activation. We presented auditory stimuli where the presence of prosodic and syntactic structure was independently manipulated during functional magnetic resonance imaging (fMRI). Three "structural" conditions included normal sentences, sentences with scrambled word order, and lists of content words. These three classes of stimuli were presented either with sentence prosody or with flat supra-lexical (list-like) prosody. Sentence stimuli activated a portion of the left anterior temporal cortex in the superior temporal sulcus (STS) and extending into the middle temporal gyrus, independent of prosody, and to a greater extent than any of the other conditions. An interaction between the structural conditions and prosodic conditions was seen in a more dorsal region of the anterior temporal lobe bilaterally along the superior temporal gyrus (STG). A post-hoc analysis revealed that this region responded either to syntactically structured stimuli or to nonstructured stimuli with sentence-like prosody. The results suggest a parcellation of anterior temporal cortex into 1) an STG region that is sensitive both to the presence of syntactic information and is modulated by prosodic manipulations (in nonsyntactic stimuli); and 2) a more inferior left STS/MTG region that is more selective for syntactic structure.
Human Brain Mapping 11/2005; 26(2):128-38. · 6.88 Impact Factor
[show abstract][hide abstract] ABSTRACT: Are the linguistic forms that are memorized in the mental lexicon and those that are specified by the rules of grammar subserved by distinct neurocognitive systems or by a single computational system with relatively broad anatomic distribution? On a dual-system view, the productive -ed-suffixation of English regular past tense forms (e.g., look-looked) depends upon the mental grammar, whereas irregular forms (e.g., dig-dug) are retrieved from lexical memory. On a single-mechanism view, the computation of both past tense types depends on associative memory. Neurological double dissociations between regulars and irregulars strengthen the dual-system view. The computation of real and novel, regular and irregular past tense forms was investigated in 20 aphasic subjects. Aphasics with non-fluent agrammatic speech and left frontal lesions were consistently more impaired at the production, reading, and judgment of regular than irregular past tenses. Aphasics with fluent speech and word-finding difficulties, and with left temporal/temporo-parietal lesions, showed the opposite pattern. These patterns held even when measures of frequency, phonological complexity, articulatory difficulty, and other factors were held constant. The data support the view that the memorized words of the mental lexicon are subserved by a brain system involving left temporal/temporo-parietal structures, whereas aspects of the mental grammar, in particular the computation of regular morphological forms, are subserved by a distinct system involving left frontal structures.
Brain and Language 06/2005; 93(2):185-238; discussion 239-42. · 3.39 Impact Factor
[show abstract][hide abstract] ABSTRACT: Previous literature has argued that proficient bilingual speakers often demonstrate monolingual-equivalent structural processing of language (e.g., the processing of structural ambiguities; Frenck-Mestre, 2002). In this paper, we explore this thesis further via on-line examination of the processing of syntactically complex structures with three populations: those who classify as monolingual native English speaker (MNES), those who classify as non-native English speakers (NNES), and those who calssify as bilingual native English speakers (BNES). On-line measures of processing of object-relative constructions demonstrated that both NNES and BNES have different patterns of performance as compared to MNES. Further, NNES and BNES speakers perform differently from one another in such processing. The study also examines the activation of lexical information in biasing contexts, and suggests that different processes are at work in the different type of bilinguals examined here. The nature of these differences and the implications for developing sensitive models of on-line language comprehension are developed and discussed.
[show abstract][hide abstract] ABSTRACT: Aims: We provide evidence that the use of perfusion imaging reveals the neuroanatomical basis for a behaviourally demonstrated cognitive deficit that is not revealed via standard neuroradiological imaging techniques. Methods & Procedures: We present a case study of a 52-year-old female stroke survivor (16 years post onset) whose speech was fluent and grammatical with some word-finding difficulties that were typically overcome with common circumlocution strategies. Based on standardised measures, the patient's clinical diagnosis was anomie aphasia. In addition to word-finding deficits, it was discovered that this patient also demonstrated difficulties in reading; while able to eventually read and understand text, there was extreme difficulty in completing such tasks. A series of experimental findings exploring this reading deficit are presented. This patient's lesion, as revealed via structural brain imaging, did not involve a brain region typically implicated in reading dysfunction. This behaviour-lesion incon-sistency was explored via perfusion MRI technology as a means of assessing whether other neural regions not directly implicated in the structural scans (such as the angular gyros) could in fact show some level of dysfunction. Outcomes & Results: Behavioural. Analysis of the patient's overall reading time demonstrated that as compared to a matched control, this patient took significantly more time in reading paragraphs both silently and aloud. In addition, the patient produced more errors (fillers, pauses, elongations) than the matched control during the reading paragraphs aloud and story-retelling conditions. There were no differences exhibited between the patient and control with respect to content accuracy produced during these conditions. Outcomes & Results: Neuroradiological. Structural images demonstrate damage to the left basal ganglia and surrounding white matter with sparing of the left insular cortex. Collection of perfusion images (pulsed arterial spin labelling) clearly demonstrates hypoperfusion in the seemingly intact brain regions of the left angular gyros and the left supramarginal gyrus. Conclusions: This paper presents evidence from a detailed case study that the use of perfusion imaging successfully reveals the neural basis for a reading deficit in a stroke survivor that is not revealed via standard "structural" neuroradiological imaging techniques. We argue for more standardised use of perfusion imaging, in that it reveals a brain basis for "functional lesions", which less sensitive neuroimaging measures often fail to capture. The authors are grateful to NIH for the grants that funded this project: DC 02984 and DC 03681. Special thanks to Edgar Zurif, Greg Hickok, and some anonymous reviewers for advice during the write-up of this report and to Elizabeth Oster, Vikki Bouck, and Matt Walenski for their assistance in data collection and analysis.
[show abstract][hide abstract] ABSTRACT: This paper presents an integrated view of the effects of context upon lexical access and lexical integration during sentence
comprehension. The review incorporates evidence from both standard psycholinguistic and neuro-cognitive approaches. Along
with this integrated overview, new hemisphere-specific processing evidence concerning context and lexical processing is presented.
The evidence is taken to support a “modes of processing” perspective in the examination of sentence comprehension.
[show abstract][hide abstract] ABSTRACT: Caplan & Waters's model differentiating levels of
processing and the role of working memory is important and likely
right. However, their claim rests on a lack of correlation between
working memory and structural complexity. We examine sources of
variability in these measures that remain unaccounted for (by anyone),
variability that muddies a straightforward claim that the lack of
correlation is cleanly established.
[show abstract][hide abstract] ABSTRACT: 1. Fixed Expressions -issues of representation and processing Understanding language involves recognition and access to not only individual words, but also to a vast array of fixed expressions -idioms, collocations, proverbs, common quotations, names, titles, slogans, song lyrics, etc. The purpose of the present paper is to examine the question of how fixed expressions -particularly those with non-literal interpretations -are understood during on-line sentence comprehension. The work we present examines cases of both truly fixed expressions and those which are deemed somewhat more malleable but stilìidiomatic', with a focus on the processing of these expressions in a language that has a highly productive (active) use of word collocation, particularly for compounds -German. We begin by outlining some general assumptions and issues underlying our work. To begin with, there is no clear ground upon which to firmly establish definitions of what constitutes a purely 'literal' vs. 'figurative' (non-literal) expression. Such definition ultimately awaits a monolithic (universal and correct) theory of semantics/syntax. Similarly, distinguishing what are truly fixed expressions vs. expressions with some productive 1 The authors gratefully acknowledge support from the grant NIH DC02984 to the second author for the work reported herein.
[show abstract][hide abstract] ABSTRACT: We present an on-line study showing different sources of lexical activation during sentence comprehension, distinguishing in this respect between reflexive syntactic and less temporarily constrained nonsyntactic sources. Specifically, we show that both the syntactic process of gap filling and a nonsyntactic end-of-sentence effect can be measurable in real time and can be temporally separated. The distinction between activation sources provides a new perspective on real-time sentence comprehension in aphasia and accounts for the disparate results reported in the literature.
Brain and Language 03/1998; 61(2):169-82. · 3.39 Impact Factor
[show abstract][hide abstract] ABSTRACT: Functional magnetic resonance imaging (fMRI), while still in relatively early stages of its development, has become a widespread tool for addressing issues in the neurobiology of language and other cognitive domains (e. g., Belliveau et al., 1991; Binder et al., 1994; Cohen et al., 1994; Hickok et al., 1995; Shaywitz et al., 1995; for a review of the technique see Bandettini et al., 1995). In a typical fMRI experiment, stimuli are presented in blocks of say 20-40 sec that alternate through several cycles with an equally long baseline/control period. So for example, a subject may see individual words presented one-at-a-time for 30 sec, then non-words for 30 sec, and so on for five cycles. This presentation scheme provides a serious constraint on experimental design in fMRI studies and consequently limits the kinds of questions one can address with this methodology. One cannot, to cite just one example, use lexical decision as a behavioral measure in the magnet because the item type (word/non-word) is fully predictable from the experi-mental design. Relatedly, under these experimental conditions it is unclear to what extent fMRI activations are due to expectation-driven (controlled) processes versus lower-level perceptual (automatic) processes. Here we present data from an alternative fMRI presentation scheme used with auditory speech perception. The paradigm is modeled on standard meth-odologies in event related potential (ERP) studies where test items are ran-
Brain and Language 07/1997; 58(1):197-201. · 3.39 Impact Factor
[show abstract][hide abstract] ABSTRACT: This paper is concerned with two related issues in sentence processing--one methodological and one theoretical. Methodologically, it provides an unconfounded test of the ability of the cross-modal lexical priming task, when used appropriately, to provide detailed evidence about the time-course of antecedent reactivation during sentence processing. Theoretically, it provides a study of the nature of the representation that is examined when a reference-seeking element is linked to its antecedent during the processing of object-relative clause constructions. In these studies, subjects heard sentences which contained a lexical ambiguity placed in a strong biasing context. In one study this ambiguous word was the "moved" or "fronted" object of the verb in an object-relative construction. A cross-modal lexical priming (CMLP) naming task was used to determine whether one or more of the meanings of the ambiguity are activated at three temporally distinct points during the sentence: (1) immediately after the lexical ambiguity (Study 1); (2) a later point that was 700 milliseconds before the offset of the main verb (Study 2); (3) immediately after this main verb (at the gap in this filler-gap construction) (Study 2). The probes in the CMLP task were controlled for potential confounds. The results demonstrate the following: At Test Point 1, all meanings of the ambiguity were activated; at Test Point 2, neither meaning of the ambiguity was (still) activated; at Test Point 3, only a single (context-relevant) meaning of the ambiguity was reactivated. It is concluded that an underlying (deep; non-surface-level) memorial representation of the sentence is examined during the process of linking an antecedent to a structural position requiring a referent, and that the CMLP task provides an unbiased measure of this reactivation. Further, it is concluded that this effect cannot be accounted for under a "compound cue" (Ratcliff & McKoon, 1994) explanation.
Journal of Psycholinguistic Research 02/1996; 25(1):5-24. · 0.59 Impact Factor
[show abstract][hide abstract] ABSTRACT: Using a cross-modal lexical priming technique we provide an on-line examination of the ability of aphasic patients to construct syntactically licensed dependencies in real time. We show a distinct difference between Wernicke's and Broca's aphasic patients with respect to this form of syntactic processing: the Wernicke's patients link the elements of dependency relations in the same manner as do neurologically intact individuals; the Broca's patients show no evidence of such linkage. These findings indicate that the cerebral tissue implicated in Wernicke's aphasia is not crucial for recovering syntactically licensed structural dependencies, while that implicated in Broca's aphasia is. Moreover, additional considerations suggest that the latter region is not the locus of syntactic representations per se, but rather provides the resources that sustain the normal operating characteristics of the lexical processing system-characteristics that are, in turn, necessary for building syntactic representations in real time.
Journal of Cognitive Neuroscience 01/1996; 8(2):174-84. · 4.49 Impact Factor