Phillip J. Holcomb

Event-related brain potentials elicited by syntactic anomaly

Abstract Event-related brain potentials (ERPs) were recorded from 13 scalp electrodes while subjects read sentences containing syntactic ambiguities. Words which were inconsitent with the “preferred” sentence structure elicited a brain potential (P600) quite distinct from the potential previously observed following contextually inappropriate words (N400). Furthermore, final words in sentences typically judged to be unacceptable elicited an N400-like effect, relative to final words in sentences typically judged to be acceptable. These findings suggest that ERPs are sensitive to syntactic anomaly, including anomaly engendered by disambiguating material following erroneous analysis of a syntactically ambiguous string (the “garden path” effect). We evaluate the speculation that the P600 and N400 effects are elicited as a function of anomaly type (syntactic and semantic, respectively).

Auditory and Visual Semantic Priming in Lexical Decision: A Comparison Using Event-related Brain Potentials

Abstract This study compared and contrasted semantic priming in the visual and auditory modalities using event-related brain potentials (ERPs) and behavioural measures (errors and reaction time). Subjects participated in two runs (one visual, one auditory) of a lexical decision task where stimuli were word pairs consisting of “prime” words followed by equal numbers of words semantically related to the primes, words unrelated to the primes, pseudo-words, and nonwords. Subjects made slower responses, made more errors, and their ERPs had larger negative components (N400) to unrelated words than to related words in both modalities. However, the ERP priming effect began earlier, was larger in size, and lasted longer in the auditory modality than in the visual modality. In addition, the lateral distribution of N400 over the scalp differed in the two modalities. It is suggested that there may be overlap in the priming processes that occur in each modality but that these processes are not identical. The results a...

Processing Syntactic Relations in Language and Music: An Event-Related Potential Study

In order to test the language-specificity of a known neural correlate of syntactic processing the P600 event-related brain potential (ERP) component, this study directly compared ERPs elicited by syntactic incongruities in language and music. Using principles of phrase structure for language and principles of harmony and key-relatedness for music, sequences were constructed in which an element was either congruous, moderately incongruous, or highly incongruous with the preceding structural context. A within-subjects design using 15 musically educated adults revealed that linguistic and musical structural incongruities elicited positivities that were statistically indistinguishable in a specified latency range. In contrast, a music-specific ERP component was observed that showed antero-temporal right-hemisphere lateralization. The results argue against the language-specificity of the P600 and suggest that language and music can be studied in parallel to address questions of neural specificity in cognitive processing.

Concreteness effects in semantic processing: ERP evidence supporting dual-coding theory.

Dual-coding theory argues that processing advantages for concrete over abstract (verbal) stimuli result from the operation of 2 systems (i.e., imaginal and verbal) for concrete stimuli, rather than just 1 (for abstract stimuli). These verbal and imaginal systems have been linked with the left and right hemispheres of the brain, respectively. Context-availability theory argues that concreteness effects result from processing differences in a single system. The merits of these theories were investigated by examining the topographic distribution of event-related brain potentials in 2 experiments (lexical decision and concrete-abstract classification). The results were most consistent with dual-coding theory. In particular, different scalp distributions of an N400-like negativity were elicited by concrete and abstract words.

The neurobiology of sensory and language processing in language-impaired children

Clinical, behavioral, and neurophysiological studies of developmental language impairment (LI), including reading disability (RD), have variously emphasized different factors that may contribute to this disorder. These include abnormal sensory processing within both the auditory and visual modalities and deficits in linguistic skills and in general cognitive abilities. In this study we employed the event-related brain potential (ERP) technique in a series of studies to probe and compare Merent aspects of functioning within the same sample of LI/RD children. Within the group multiple aspects of processing were affected, but heterogeneously across the sample. ERP components linked to processing within the superior temporal gyrus were abnormal in a subset of children that displayed abnormal performance on an auditory temporal discrimination task. An early component of the visual ERP was reduced in amplitude in the group as a whole. The relevance of this effect to current conceptions of substreams within the visual system is discussed. During a sentence processing task abnormal hemispheric specialization was observed in a subset of children who scored poorly on tests of grammar. By contrast the group as a whole displayed abnormally large responses to words requiring contextual integration. The results imply that multiple factors can contribute to the profile of language impairment and that different and specific deficits occur heterogeneously across populations of LI/RD children.

An electrophysiological investigation of semantic priming with pictures of real objects

Event-related potentials were recorded using color pictures of real objects. Participants made relatedness judgments for pictures that were highly, moderately, or unrelated to a picture of a preceding prime object (Experiment 1) or object identification decisions for related/easily identified, unrelated/easily identified, and unrelated/unidentifiable objects preceded by prime objects (Experiment 2). Unrelated pictures elicited larger event-related potential negativities between 225 and 500 ms than did related pictures, although the first portion of this epoch had a more frontal distribution than did the later portion. The later epoch differentiated the unrelated from the moderately related and the moderately related from the highly related pictures (Experiment 1), but the early epoch produced differences only between the unrelated and related pictures (Experiments 1 and 2). This pattern supports the existence of two separate components, an anterior, image-specific N300 and a later, central/parietal amodal N400.

An Electrophysiological Study of the Effects of Orthographic Neighborhood Size on Printed Word Perception

In two experiments participants read words and pseudo-words that belonged to either large or small lexical neighborhoods while event-related brain potentials (ERPs) were recorded from their scalps. In Experiment 1, participants made speeded lexical decisions to all items, while in Experiment 2 they engaged in a go/no-go semantic categorization task in which the critical items did not require an overt behavioral response. In both experiments, words and pseudo-words produced a consistent pattern of ERP effects: items with many lexical neighbors (large neighborhoods) generated larger N400s than similar items with relatively fewer lexical neighbors (small neighborhoods). Reaction time (RT, Experiment 1), on the other hand, showed a different pattern consistent with previous behavioral studies. While words tended to produce a facilitation in RT for larger neighborhoods, pseudowords produced an inhibition effect. The findings are discussed in terms of recent theories of word recognition and the functional significance of the N400.

On the Time Course of Visual Word Recognition: An Event-related Potential Investigation using Masked Repetition Priming

The present study used event-related potentials (ERPs) to examine the time course of visual word recognition using a masked repetition priming paradigm. Participants monitored target words for occasional animal names, and ERPs were recorded to nonanimal critical items that were full repetitions, partial repetitions, or unrelated to the immediately preceding masked prime word. The results showed a strong modulation of the N400 and three earlier ERP components (P150, N250, and the P325) that we propose reflect sequential overlapping steps in the processing of printed words.

Event-related potentials and syntactic anomaly: Evidence of anomaly detection during the perception of continuous speech

Abstract Event-related brain potentials (ERPs) were recorded from 13 scalp electrodes while subjects listened to sentences containing syntactic ambiguities. Words that were inconsistent with the “preferred” sentence structure elicited a positive-going wave (the P600 effect), similar to that elicited by such words during reading (Osterhout & Holcomb, 1992). These results suggest that (1) ERPs recorded during the comprehension of spoken sentences are sensitive to the syntactic anomaly engendered by disambiguating material following erroneous analysis of a syntactically ambiguous string (the “garden-path” effect), (2) the parsing strategies employed during sentence comprehension are (in some circumstances) constant across modalities, and (3) syntactic analysis of spoken sentences is temporally close to the acoustic input.

Visual and auditory sentence processing: A developmental analysis using event‐related brain potentials

Subjects aged 5 to 26 years listened to and read (7 to 26 years) sentences that ended either with a highly expected (best completion) or a semantically inappropriate (anomalous completion) word. Event‐related potentials (ERPs) to sentence final words displayed effects of contextual priming in both modalities in all age groups. Early and late ERP components displayed large decreases in amplitude and latency with age. These changes necessitated normalization procedures so that overall changes in amplitude with age could be assessed separately from changes in the amplitude of the differences between best‐completion and anomalous‐completion words. There were significant reductions in the contextual priming effects with age. Moreover, these age‐related changes were different for the auditory and visual modalities, and for the early and later phases of the priming effect. These results suggest that nonidentical systems, with different developmental time courses, generate the early and late priming effects in th...