bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Processing Nature of the N400: Evidence from Masked Priming
Authors: Brown Colin , Hagoort Peter 
Published: February 2008

Abstract
The N400 is an endogenous event-related brain potential (ERP) that is sensitive to semantic processes during language comprehension. The general question we address in this paper is which aspects of the comprehension process are manifest in the N400. The focus is on the sensitivity of the N400 to the automatic process of lexical access, or to the controlled process of lexical integration. The former process is the reflex-like and effortless behavior of computing a form representation of the linguistic signal, and of mapping this representation onto corresponding entries in the mental lexicon. The latter process concerns the integration of a spoken or written word into a higher-order meaning representation of the context within which it occurs. ERPs and reaction times (RTs) were acquired to target words preceded by semantically related and unrelated prime words. The semantic relationship between a prime and its target has been shown to modulate the amplitude of the N400 to the target. This modulation can arise from lexical access processes, reflecting the automatic spread of activation between words related in meaning in the mental lexicon. Alternatively, the N400 effect can arise from lexical integration processes, reflecting the relative ease of meaning integration between the prime and the target. To assess the impact of automatic lexical access processes on the N400, we compared the effect of masked and unmasked presentations of a prime on the N400 to a following target. Masking prevents perceptual identification, and as such it is claimed to rule out effects from controlled processes. It therefore enables a stringent test of the possible impact of automatic lexical access processes on the N400. The RT study showed a significant semantic priming effect under both unmasked and masked presentations of the prime. The result for masked priming reflects the effect of automatic spreading of activation during the lexical access process. The ERP study showed a significant N400 effect for the unmasked presentation condition, but no such effect for the masked presentation condition. This indicates that the N400 is not a manifestation of lexical access processes, but reflects aspects of semantic integration processes.
Plurality of Viual Mismatch Potentials in a Reptile
Authors: Prechtl James C. , Bullock Theodore H. 
Published: February 2008

Abstract
Studies with auditory stimuli have established in humans that a mismatch potential (MMP) is elicited whenever a deviant stimulus is substituted for a standard stimulus in a train of monotonous standard stimuli presented at rates &gt; 0.25 Hz. The MMP in humans is localized in the auditory cortex and is known as mismatch negativily, from its polarity in scalp recordings. It is hypothesized to reflect the operation of sensory memory and to be a necessary component of the auditory orienting response.
To examine the generality of MMPs we used a visual mismatch paradigm with pond turtles (Pseudemys scripta) while recording with electrode arrays (200 μm spacing) from near surface and deep visual projection areas within the forebrain and optic tectum. Standard stimuli were 10-sec trains of diffused strobe flashes presented at rates of 1-6 Hz against backgrounds of 2-11 lux. Deviant stimuli were brighter or dimmer flashes that followed the last standard flash. MMps were separated from visual evoked potentials by subtracting the response to the last standard flash of the train from the response to the same flash (bright or dim) when delivered as a deviant. Comparisons were also made with evoked potentials to isolated bright or dim flashes, that is, equal in frequency (1 per 12 sec) to the deviants but without intervening standard flashes.
At tectal loci bright and dim deviants elicited net positivities that reached statistical significance in the period between 141 ± 8 and 184 ± 12 msec after the deviant stimulus (mean ± SEM). Earlier components in the tectal responses correlated with the intensity of the stimulus rather than its deviance. In the case of the bright deviants the early waves (P50-P75) were larger in amplitude. Forebrain recordings showed a similar although broader period of net positivity, associated with deviance, between 129 ± 8 and 195 ± 12 msec. Deviants, delivered as isolated flash responses evoked larger early components (100-140 msec). In separate experiments with cortical epipial electrodes, a condition somewhat more comparable to scalp recording, MMPs were similar in latency but had a negative polarity.
Regression analyses revealed a relationship between the amplitude (base-to-peak) of the MMF' and the degree to which the standard response had declined with repeated stimulation. Rate decrement, as measured by the isolated (long ISI) flash response minus the last standard response, was a significant predictor of MMP amplitudes (r 2 = 0.37, tectum; r 2 = 0.31, forebrain), whereas standard response amplitudes alone were not (r 2 = 0.09; r 2 = 0.06).
MMPs are present in nonmammals plurally, that is, at different levels of the visual system, at least as early as the tectum. The existence of subcortical MMPs caution against assigning a primary or exclusive role to those recorded from the cortex.
The Neurobiology of Sensory and Language Processing in Language-Impaired Children
Authors: Neville Helen J. , Coffey Sharon A. , Holcomb Phillip J. , Tallal Paula 
Published: February 2008

AbstractClinical, 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 Assessment of the Semantic Network in Patients with Alzheimer's Disease
Authors: Chan Agnes S. , Butters Nelson , Paulsen Jane S. , Salmon David P. , Swenson Michael R. , Maloney Laurence T. 
Published: February 2008

Abstract
The present study employed multidimensional scaling and ADDTREE clustering analyses to derive the cognitive maps and clustering representations of normal elderly controls (NC), patients with Alzheimer's disease (AD), and patients with Hun-tington's disease (HD); the analyses were performed on subjects' responses in a category fluency task that involved generating animal names for 60 sec. A measure of the proximity of animal names was used as an index of associational strength; MDS and ADDTREE estimates were based on this measure. A comparison of the NC, AD, and HD subjects' cognitive maps suggests that the semantic network of AD patients is abnormal in two ways. First, the organization of the semantic network is disrupted. Second, new abnormal associations and clusterings are formed. These results support the notion that AD is characterized by a breakdown in the structure of semantic knowledge and not primarily by a deficiency in the accessibility of semantic information.
Language Acquisition and Cerebral Specialization in 20-Month-Old Infants
Authors: Mills Debra L. , Coffey-Corina Sharon A. , Neville Helen J. 
Published: February 2008

Abstract
The purpose of the present study was to examine patterns of neural activity relevant to language processing in 20-month-old infants, and to determine whether or not changes in cerebral organization occur as a function of specific changes in language development. Event-related potentials (ERPs) were recorded as children listened to a series of words whose meaning was understood by the child, words whose meaning the child did not understand, and backward words. The results showed that specific and different ERP components discriminated comprehended words from unknown and from backward words. Distinct lateral and anterior-posterior specializations were apparent in EW responsiveness to the different types of words. Moreover, the results suggested that increasing language abilities were associated with increasing cerebral specialization for language processing over the temporal and parietal regions of the left hemisphere.
The Cortical Representation of Speech
Authors: Mazoyer B. M. , Tzourio N. , Frak V. , Syrota A. , Murayama N. , Levrier O. , Salamon G. , Dehaene S. , Cohen L. , Mehler J. 
Published: February 2008

Abstract
In this study, we compare regional cerebral blood flow (rCBF) while French monolingual subjects listen to continuous speech in an unknown language, to lists of French words, or to meaningful and distorted stories in French. Our results show that, in addition to regions devoted to single-word comprehension, processing of meaningful stories activates the left middle temporal gyrus, the left and right temporal poles, and a superior prefrontal area in the left frontal lobe. Among these regions, only the temporal poles remain activated whenever sentences with acceptable syntax and prosody are presented.
The Impact of Semantic Memory Loss on Phonological Representations
Authors: Patterson Karalyn , Graham Naida , Hodges John R. 
Published: February 2008

AbstractThree patients with semantic dementia, involving progressive deterioration of semantic memory, performed immediate serial recall of short sequences of familiar words. On the basis of their performance in other tasks of word comprehension and production, the stimuli were selected individually for each patient as either known or unknown words. All patients showed a marked advantage in recall of known as compared to familiar but now unknown words. Errors consisted primarily of incorrect combinations of correct phoneme sequences in the stimulus string, with a large number of errors preserving onsethime syllable structure (e.g., mint, rug reproduced as “rint, mug”). Discussion focuses on the implication of these errors for the structure of phonological representations, and in particular on a hypothesis that meaning plays a crucial role in binding the elements of phonological word forms.
Categorical versus Coordinate Spatial Processing: Effects of Blurring and Hemispheric Asymmetry
Authors: Cowin Elizabeth L. , Hellige Joseph B. 
Published: February 2008

Abstract
The present experiment examined the effects of dioptric blurring on the performance of two different spatial processing tasks using the same visual stimuli. One task (the above/below, categorical task) required subjects to indicate whether a dot was above or below a horizontal line. The other task (the coordinate, near/far task) required subjects to indicate whether the dot was within 3 mm of the line. For both tasks, the stimuli on each trial were presented to either the right visual field and left hemisphere (RVF/LH) or the left Visual field and right hemisphere (LVF/RH). For the above/below task, dioptric blurring consistently increased reaction time (RT) and did so equally on LVF/RH and RVF/LH trials. Furthermore, there was no significant difference between the two visual fields for either clear or blurred stimuli. For the near/far task, dioptric blurring had no consistent effect on either RT or error rate for either visual field. On an initial block of trials, however, there were significantly fewer errors on LVF/RH than on RVF/LH trials, with the LVF/RH advantage being independent of whether the stimuli were clear or blurred. This initial LVF/RH advantage disappeared quickly with practice, regardless of whether the stimuli were clear or blurred. This pattern of results suggests that for both cerebral hemispheres, somewhat different aspects of visual information are relevant for categorical versus coordinate spatial processing and that the right hemisphere is superior to the left for coordinate (but not categorical) spatial processing.
Memory Representations in Natural Tasks
Authors: Ballard Dana H. , Hayhoe Mary M. , Pelz Jeff B. 
Published: February 2008

Abstract
The very limited capacity of short-term or working memory is one of the most prominent features of human cognition. Most studies have stressed delimiting the upper bounds of this memory in memorization tasks rather than the performance of everyday tasks. We designed a series of experiments to test the use of short-term memory in the course of a natural hand-eye task where subjects have the freedom to choose their own task parameters. In this case subjects choose not to operate at the maximum capacity of short-term memory but instead seek to minimize its use. In particular, reducing the instantaneous memory required to perform the task can be done by serializing the task with eye movements. These eye movements allow subjects to postpone the gathering of task-relevant information until just before it is required. The reluctance to use short-term memory can be explained if such memory is expensive to use with respect to the cost of the serializing strategy.
The Nature of Preattentive Storage in the Auditory System
Authors: Gomes Hilary , Ritter Walter , Vaughan Herbert G. 
Published: February 2008

Abstract
Event-related potentials were recorded to tones that subjects ignored while reading a book of their choosing. In all conditions, 90% of the tones were 100 msec in duration and 10% of the tones were 170 msec in duration. In a control condition, a customary oddball paradigm was used in which all of the tones were identical except for the longer duration tones. In two conditions, the tones varied over a wide range of tonal frequencies from 700 to 2050 Hz in 10 steps of 150 Hz. In another condition, the tones varied over the same frequencies but also varied in intensity from about 60 to 87 dB in steps of 3 dB. Thus, there was no “standard” tone in the sense of a frequently presented tone that had identical stimulus features. A mismatch negativity (MMN) was elicited in all conditions. The data are discussed in terms of the storage of information in the memory upon which the MMN is based.
ERP Measures Assay the Degree of Expectancy Violation of Harmonic Contexts in Music
Authors: Janata Petr 
Published: February 2008

Abstract
Expectancy violations of a highly constrained musical context were studied by presenting subjects with a chord sequence (I, IV, V) that generated a strong expectancy for a specific final chord, and then completing the sequence with either a “best-possible” (Tonic), harmonically plausible (Minor), or harmonically implausible (Dissonant) resolution. Subjects determined whether it was the best-possible resolution, and in one-half of the trials made their decision known with an overt response. Several ERP waveform components showed differences among resolution types, response conditions, and electrode locations. Among the affected components were two subclasses of the P300, the first of which (P3a) was largest in response to the Dissonant in both response conditions at all electrode sites. The area and peak amplitude of the P3b varied at several electrode sites as a function of the degree of expectancy violation represented by the resolutions. The peak latency of the P3b component reflected the behavioral response time measurement in which the Tonic and Dissonant were identified 300 msec more quickly than the Minor. A comparison between frequency and timedomain data analyses demonstrates several parallels, and it is concluded that both can serve to investigate the perception and processing of the probability structure underlying musical events and contexts.
Inducing Agrammatic Profiles in Normals: Evidence for the Selective Vulnerability of Morphology under Cognitive Resource Limitation
Authors: Blackwell Arshavir , Bates Elizabeth 
Published: February 2008

Abstract
The selective vulnerability of morphology in agrammatic aphasia is often interpreted as evidence that closedclass items reside in a particular part of the brain (i.e., Broca's area); thus, damage to a part of the language processor maps onto behavior in a transparent fashion. We propose that the selective vulnerability of grammatical morphemes in receptive processing may be the result of decrements in overall processing capacity, and not the result of a selective lesion. We demonstrate agrammatic profiles in healthy adults who have their processing capacity diminished by engaging in a secondary task during testing. Our results suggest that this selective profile does not necessarily indicate the existence of a distinct subsystem specialized for the implicated aspects of syntax, but rather may be due to the vulnerability of these forms in the face of global resource diminution, at least in grammaticality judgment.
Surface Area of Human Cerebral Cortex and Its Gross Morphological Subdivisions:In VivoMeasurements in Monozygotic Twins Suggest Differential Hemisphere Effects of Genetic Factors
Authors: Tramo Mark Jude , Loftus William C. , Thomas Catherine E. , Green Ronald L. , Mott Leila A. , Gazzaniga Michael S. 
Published: February 2008

AbstractWe measured the surEdce area of the cerebral cortex and its gross morphological subdivisions in 10 pairs of monozygotic twins. Cortical surface area was estimated in vivo using magnetic resonance imaging and threedimensional computer models of the intra- and extrasulcal pial surface. The means and standard deviations of regional (e.g., gyral), lobar, hemisphere, and total cortical surface area were tabulated for the entire population of 20 young, right-handed adults (10 females, 10 males). To determine whether genotypic differences were associated with morphometric differences, analyses of variance were carried out on each measure across unrelated twin pairs (genotype factor) and within co-twins (birth order factor). Across unrelated pairs, there was wide variation in regional cortical surface area for the left hemisphere (normalized by total cortical surface area, p ≤ 0.0001) but not for the right hemisphere (normalized, p = 0.12). More variation in lobar surface area was also observed for the left hemisphere (normalized, p = 0.05) than for the right (normalized, p = 0.48). Within co-twins, no signifcant variation in regional surface area or lobar surface area was found for the left or right hemisphere. Although normalized regional and lobar surface area in the left hemisphere differed across unrelated pairs, overall left hemisphere surface area normalized by total cortical surface area did not (p = 0.73). Total cortical surface area normallzed by body weight varied across unrelated pairs (p = 0.001) but not within co-twins (p = 0.39). The effects observed across unrelated pairs were not attributable to sex differences.These results suggest: 1) both the total area and folding of the cortical surface are heavily influenced by genetic factors in humans; and 2) the cerebral hemispheres may be differentially affected by genetic influences on cortical morphogenesis, with the languagedominant left cerebral cortex under stronger genetic control than the right.
Cognitive and Neural Mechanisms Underlying Visual and Semantic Processing: Implications from “Optic Aphasia”
Authors: Hillis Argye E. , Caramazza Alfonso 
Published: February 2008

Abstract
We report detailed analyses of the performance of a patient, DHY, who as a consequence of strokes in the left occipital lobe and the periventricular white matter in the region of the spleniuni, showed severely impaired naming of visual stimuli despite spared recognition of visual stimuli and spared naming in other modalities. This pattern of performance—labeled “optic aphasia”—has been previously interpreted as support for the hypothesis that there are independent semantic systems, either a visual and a verbal semantic store (Beauvois, 1982; Lhermitte & Beauvois, 1973) or a right hemisphere and a left hemisphere semantic system (Coslett & Saffran, 1989, l092), which are “disconnected” in these patients. We provide evidence that DHY shows precisely the types of performance across a variety of verbal and visual tasks that have been used to support these claims of separate semantic systems: (1) good performance in naming to definition and naming objects presented for tactile exploration (which has been interpreted as evidence of spared verbal or left hemisphere semantic processing), and (2) good performance on various “semantic” tasks that do not require naming (which has been interpreted as access to spared visual or right hemisphere semantic processing). Nevertheless, when nonverbal semantic tasks were modified such that they required access to more detailed semantic information for accurate performance, DHY was Par less accurate, indicating that she did not access complete semantic information about objects in the visual modality. We argue that these data undermine the claim that cases of optic aphasia can be explained only by proposing multiple semantic systems. We propose an alternative account for this pattern of performance, within a model of visual object naming that specifies a single, modality-independent semantic system. We show that the performance of DHY and other “optic aphasic” patients can be explained by proposing a deficit in accessing a complete, modality-independent, lexical-semantic representation from an intact stored, structural description of the object. We discuss the implications of these conclusions for claims about the neuroanatomical correlates of semantic and visual object processing.
Functional Mapping of Sequence Learning in Normal Humans
Authors: Grafton Scott T. , Hazeltine Eliot , Ivry Richard 
Published: February 2008

Abstract
The brain localization of motor sequence learning was studied in normal subjects with positron emission tomography. Subjects performed a serial reaction time (SRT) task by responding to a series of stimuli that occurred at four different spatial positions. The stimulus locations were either determined randomly or according to a 6-element sequence that cycled continuously. The SRT task was performed under two conditions. With attentional interference from a secondary counting task there was no development of awareness of the sequence. Learning-related increases of cerebral blood flow were located in contralateral motor effector areas including motor cortex, supplementary motor area, and putamen, consistent with the hypothesis that nondeclarative motor learning occurs in cerebral areas that control limb movements. Additional cortical sites included the rostral prefrontal cortex and parietal cortex. The SRT learning task was then repeated with a new sequence and no attentional interference. In this condition, 7 of 12 subjects developed awareness of the sequence. Learning-related blood flow increases were present in right dorsolateral prefrontal cortex, right premotor cortex, right ventral putamen, and biparieto-occipital cortex. The right dorsolateral prefrontal and parietal areas have been previously implicated in spatial working memory and right prefrontal cortex is also implicated in retrieval tasks of verbal episodic memory. Awareness of the sequence at the end of learning was associated with greater activity in bilateral parietal, superior temporal, and right premotor cortex. Motor learning can take place in different cerebral areas, contingent on the attentional demands of the task.