bluuebunny/crossref_metadata_2025_split huggingface dataset:
Behavioral Indices of Multisensory Integration: Orientation to Visual Cues is Affected by Auditory Stimuli
Authors: Stein Barry E. , Meredith M. Alex , Huneycutt W. Scott , McDade Lawrence 
Published: February 2008

Abstract
Physiological studies have demonstrated that inputs from different sensory modalities converge on, and are integrated by, individual superior colliculus neurons and that this integration is governed by specific spatial rules. The present experiments were an attempt to relate these neural processes to overt behavior by determining if behaviors believed to involve the circuitry of the superior colliculus would show similar multisensory dependencies and be subject to the same rules of integration.
The neurophysiological-behavioral parallels proved to be striking. The effectiveness of a stimulus of one modality in eliciting attentive and orientation behaviors was dramatically affected by the presence of a stimulus from another modality in each of the three behavioral paradigms used here. Animals trained to approach a low intensity visual cue had their performance significantly enhanced when a brief, low intensity auditory stimulus was presented at the same location as the visual cue, but their performance was significantly depressed when the auditory stimulus was disparate to it. These effects were independent of the animals' experience with the modifying (i.e. auditory) stimulus and exceeded what might have been predicted statistically based on the animals' performance with each single-modality cue. The multiplicative nature of these multisensory interactions and their dependence on the relative positions and intensities of the two stimuli were all very similar to those observed physiologically for single cells. The few differences that were observed appeared to reflect the fact that understanding integration at the level of the single cell requires reference to the individual cell's multisensory receptive field properties, while at the behavioral level populations of receptive fields must be evaluated. These data illustrate that the rules governing multisensory integration at the level of the single cell also predict responses to these stimuli in the intact behaving organism.
The Effects of Focal Brain Damage on Sentence Processing: an examination of the neurological organization of a mental module
Authors: Swinney David , Zurif Edgar , Nicol Janet 
Published: February 2008

Abstract
The effects of prior semantic context upon lexical access during sentence processing were examined for three groups of subjects; nonfluent agrammatic (Broca's) aphasic patients; fluent (Wernicke's) aphasic patients; and neurologically intact control patients. Subjects were asked to comprehend auditorily presented, structurally simple sentences containing lexical ambiguities, which were in a context strongly biased toward just one interpretation of that ambiguity. While listening to each sentence, subjects also had to perform a lexical decision task upon a visually presented letter string. For the fluent Wernicke's patients, as for the controls, lexical decisions for visual words related to each of the meanings of the ambiguity were facilitated. By contrast, agrammatic Broca's patients showed significant facilitation only for visual words related to the a priori most frequent interpretation of the ambiguity. On the basis of these data, we suggest that normal form-based word retrieval processes are crucially reliant upon the cortical tissue implicated in agrammatism, but that even the focal brain damage yielding agrammatism does not destroy the normally encapsulated form of word access. That is, we propose that in agrammatism, the modularity of word access during sentence comprehension is rendered less efficient but not lost. Additionally, we consider a number of broader issues involved in the use of pathological material to infer characteristics of the neurological organization of cognitive architecture.
Brain Activity Underlying Mental Imagery: Event-related Potentials During Mental Image Generation
Authors: Farah Martha J. , Weisberg Lauren L. , Monheit Mark , Peronnet Franck 
Published: February 2008

Abstract
This article addresses two issues about the neural bases of mental imagery. The first issue concerns the modality-specificity of mental images, that is, whether or not they involve activity in visual areas of the brain. The second issue concerns hemispheric specialization for the generation of mental images. We compared event-related potentials recorded under two conditions: one in which subjects were shown words and asked to read them and one in which subjects were shown words and asked to read them and generate visual mental images of the words' referents. Imagery caused a slow, late positivity, maximal at the occipital and posterior temporal regions of the scalp, relative to the comparison condition, and consistent with the involvement of modality-specific visual cortex in mental imagery. Also noted was an asymmetry in the imagery-related ERP, consistent with left-hemisphere specialization for mental image generation. Similar results were obtained when subjects listened to auditorily presented words with and without instructions to generate mental images. To assess the specificity of the relation between these ERP effects and mental imagery, we compared the ERP changes brought about by imaging with those brought about by another effortful task using the same stimulus words: proofreading the words for occasional misspellings. This produced changes that differed in polarity, time course, and scalp distribution from the imagery-related changes.
The Temporal Dynamics of Event Memory: A Stage Analysis of Mnemonic Processing by Man and Macaque
Authors: Lawine Jeffrey David 
Published: February 2008

Abstract
Extensive anatomical and psychophysical data suggest that macaques can serve as surrogates for man in studies of the neural substrates of visual mnemonic processing. However, the extent to which mnemonic-mechanisms in macaques can be validly compared to those in man depends critically on the demonstration that the cognitive strategy and temporal dynamics of mnemonic retrieval are congruent For the two species.
Seven human and six macaque subjects were tested on identical versions of an item recognition task that required the classification of probe stimuli as positive or negative according to whether or not they were members of a previously defined set of target stimuli. For the human subjects, reaction time increased by an average of 24 msec/target. The macaques were able to respond as accurately as the human subjects, but each additional target resulted in a reaction time increment of only 7 msec. A detailed analysis of the statistical properties of the reaction-time distributions indicated that these data do not reflect a between-species difference in the efficiency of execution of otherwise comparable, serial-exhaustive, retrieval mechanisms. Rather, the data suggest that human subjects engage two memory-load dependent processes before generating a response, while macaques execute only one of these.
Additional data indicate that a reaction-time approach toward the analysis of the stages of mnemonic processing can provide new insights into the specific nature of mnemonic deficits induced by brain damage.
Spatially Distributed Cortical Excitation Patterns of Auditory Processing during Contralateral and Ipsilateral Stimulation
Authors: Rogers Robert L. , Papanicolaou Andrew C. , Baumann Stephen B. , Eisenberg Howard M. , Saydjari Christy 
Published: February 2008

Abstract
Utilizing the high spatial and temporal resolution of magnetoencephalography in conjunction with magnetic resonance images, the current study explored the underlying electrical patterns of cortical excitation during both contralateral and ipsilateral auditory stimulation. Instead of studying only the peaks of the N100 component of the evoked magnetic field, a 30-msec window was chosen about the area where the peaks occurred and the intracranial sources generating that component were estimated at successive 5-msec intervals. Results indicated that the sources for both contralateral and ipsilateral conditions were best represented as a continuous movement of activation in an anterior–inferior direction along the superior surface of the temporal lobe. Although the peak magnetic fields of the N100 to contralateral stimulation were of shorter latency and higher amplitude, the generating sources of both had very similar time-dependent movement patterns, and comparisons of source localizations were dependent on the latency at which they were contrasted.
The Bounded Brain: Toward Quantitative Neuroanatomy
Authors: Cherniak Christopher 
Published: February 2008

Abstract
An idea that human cognitive resources are virtually without limit turns up at all levels of mind/brain science. This tacit unbounded-resource assumption has paradoxical consequences in neuroscience, particularly involving the quantitative incoherence of some key anatomical studies of cortical connectivity resources: cortical sheet area, synaptic density there, and giant axonic arborizations in visual cortex. This inattention to quantitative consistency checking in neuroanatomy appears to stem from, as a notable instance, something of the nonspatial character of the Cartesian concept of mind being extended to the brain as physical structure.
Thalamic and Cortical Mechanisms of Attention Suggested by Recent Positron Emission Tomographic Experiments
Authors: LaBerge David 
Published: February 2008

Abstract
An attention mechanism in the pulvinar nucleus of the thalamus appears to be involved in the filtering of a location in a cluttered visual field, according to recent PET data. The mechanism in the pulvinar is assumed to be a particular type of circuit that reciprocally connects thalamic relay cells to cortical cells. This circuit, which is characteristic of thalamic nuclei in general, appears to embody an algorithm that enhances firing in a target set of cells while inhibiting firing in the surrounding set of cells. Recent PET studies have also identified specific areas of cortex that show increased blood flow when humans expect to process particular aspects of visual objects, such as location, shape, color, and movement velocity. An expectation for a particular feature can be regarded as a peaked activity distribution across cortical synaptic space that increases the effectiveness (accuracy and speed) of the perception of that feature and features similar to that feature. The expectation process is assumed to be generated by a thalamic enhancement circuit, which in turn is driven by a cognitive procedure, apparently located in the anterior cingulate area of the cortex. The selection of a particular cognitive procedure is assumed to depend on the momentary relative motivational value associated with it by means of connections to deeper limbic structures. Under usual conditions, the procedure having the dominant motivational value is the one selected.
Arm Trajectory Modifications During Reaching Towards Visual Targets
Authors: Flash Tamar , Henis Ealan 
Published: February 2008

Abstract
In this paper we study the question of how an aimed arm movement is modified in response to a sudden change in target location occurring during the reaction or movement time. Earlier monkey and human studies demonstrated that aimed arm movements can be elicited in quick succession, without appreciable delays in responding to the target displacement, beyond the normal reaction time. Nevertheless, it is not yet clear how this motor task is performed. A first guess is that when a new visual stimulus appears the old plan is aborted and a new one conceived. Upon analyzing human arm movements, however, we find that the observations can be well accounted for by a different movement modification scheme. It appears that a new plan is vectorially added to the original plan. Among the implications of this result is the possibility of parallel planning of elemental movements and further support for the idea that arm movements are internally represented in terms of hand motion through external space.
Differential Sensitivity to Errors of Agreement and Word Order in Broca's Aphasia
Authors: Wulfeck Beverly , Bates Elizabeth 
Published: February 2008

Abstract
We investigated the effect of morphosyntactic violation type on accuracy and processing time in Broca's aphasics engaged in an on-line error detection task. Five agrammatic Broca's aphasic subjects and 15 age-matched control subjects performed grammaticality judgments on auditorily presented grammatical and ungrammatical sentences. Both judgment accuracy and decision time were measured, so that the data revealed not only whether aphasics detected violations, but when they noticed them. The ungrammatical sentences were created by changing quantifiers and auxiliary verbs in one of two ways: substituting one quantifier or auxiliary for another to create agreement errors, or moving the quantifier or auxiliary “downstream” from its proper site to create word order errors. Also, the position of the violation in the sentence (early versus late) as well as the distance relationships among sentence elements involved in the violation (local versus global) were manipulated.
Results suggest that aphasic subjects retain some sensitivity to grammaticality, knowledge that they are able to use “online.” Performance was also affected by type of violation. Aphasic subjects were less sensitive to agreement violations than they were to violations created by moving the same elements to an illegal position—and this tended to be reflected in decision times as well as accuracy.
These results support two conclusions. First, although the performance of aphasic subjects was degraded relative to control subjects, the findings of overall grammaticality sensitivity and relatively rapid decision times suggest that the locus of grammatical impairment in these patients has more to do with the accessing of linguistic information than with loss of linguistic knowledge. Second, the difference between agreement and movement violations provides further evidence that morphological marking is relatively vulnerable in aphasia, compared with the principles that govern word and morpheme ordering.
Development of Spontaneous Alternation in Infancy
Authors: Vecera* Sham P. , Rothbart Mary K. , Posner Michael I. 
Published: February 2008

Abstract
Spontaneous alternation is a reduced tendency to return to the same location on successive trials. It is measured in rats in a T maze and is thought to depend on an intact hippocampus. In human infants, we measured alternation in the tendency to reach toward one of two identical toys placed in locations to the left and right of midline. Infants at 6 months returned to the same side as frequently as they alternated, but 18--month-old infants showed a significant alternation pattern. At 6 months, infants show inhibition of return, but do not show alternation in motor behavior; at 18 months, infants show both, but they are negatively related. These data suggest that preference for novelty may rest on different internal mechanisms even in quite similar tasks, and suggest that whereas inhibition of return is related to control by the posterior attention network, spontaneous alternation may be related to inhibitory control by the anterior attention network.
The Psychophysical Attributes of Heat-Induced Pain and Their Relationships to Neural Mechanisms
Authors: Price Donald D. , McHaffie John G. , Stein Barry E. 
Published: February 2008

Abstract
During the last two decades there has been a proliferation of studies evaluating the psychophysical and neural attributes of heat-induced pain. Experiments using radiant and contact heat-induced pain have produced different observations thereby broadening our appreciation of the importance of acknowledging how a noxious heat stimulus is delivered; moreover manipulations of stimulus parameters have now provided a foundation for understanding the underlying neural mechanisms of heat-induced pain and their biological significance. The psychophysical attributes of heat-induced pain include highly reliable thresholds for most body regions, minimal adaptation to maintained noxious stimuli, an exquisite sensitivity to small changes in stimulus intensity, slow temporal summation for some types of heat-induced pain (i.e., second pain) but not for others (i.e., first pain), spatial summation---especially for suprathreshold noxious temperatures---and the perceived spread of pain well beyond the actual body area stimulated (i.e., radiation). The present body of information indicates that the pain system is optimally adapted for conveying precise information about intensity, and is less concerned with other stimulus features, such as spatial patterns or boundaries.
Preserved Visual Imagery and Categorization in a Case of Associative Visual Agnosia
Authors: Jankowiak Janet , Kinsbourne Marcel , Shalev Ruth S. , Bachman David L. 
Published: February 2008

Abstract
A patient with associative visual agnosia secondary to a penetrating bitemporooccipital lesion remained able to draw complex objects from memory but could not subsequently recognize his sketches. His retained ability to copy and draw briefly exposed objects indicates that this is not a problem of visual perception. On tasks of categorization, mental imagery, drawing, and object decision, he demonstrates many instances of preserved visual semantic memories and imagery despite a sense of unfamiliarity with the visual stimuli. We infer a preserved ability to derive internal visual images from semantic memory. Cues may help him visualize the named object, which then serves as a model for comparison with the actual stimulus. However, his adequate visual perception and mental visual imagery, even when assisted by cues, are still insufficient to correct fully his difficulty in recognizing objects. Unique to his case is an inability to match the representation of stimulus objects with his intact internal image of the same object. Deficient lateral inhibition between neural representations of similar objects may be responsible.
Modes of Lexical Access in the Callosotomized Brain
Authors: Reuter-Lorenz Patricia A. , Baynes Kathleen 
Published: February 2008

AbstractLeft hemisphere processing is typically characterized as analytic and serial whereas the right hemisphere is characterized as wholistic and parallel. Word recognition may be an exception to this dichotomy if the letter-by-letter alexia produced by left hemisphere damage reflects the reading abilities of the right hemisphere. We investigated this possibility by studying prelexical and lexical processes in the separated hemispheres of callosotomy patient J. W. A word superiority effect demonstrated in each visual field suggests that both hemispheres have access to a visual lexicon. Error patterns, letter recognition thresholds, and lexical decision performance as a function of word length suggest that the left hemisphere tends to utilize a parallel access mode, whereas the right hemisphere mode is less efficient and may be serial. Furthermore, only J. W.'s left hemisphere showed letter priming, an outcome consistent with observations in letter-by-letter alexia. These findings suggest that the right hemisphere may have an independent visual lexicon and may provide an alternative although less efficient route to reading. We suggest that a serial encoding strategy results because the global processing mode for which the right hemisphere is specialized is largely ineffective for word reading.
Effects of Multiple Stimuli on Ocular Orientation by Cats
Authors: Kurylo Daniel D. , Pandey Vimal Ram L. , Hartline Peter H. 
Published: February 2008

Abstract
We investigated the characteristics of saccades made by cats in response to single and double stimuli. Stimuli were either visual, auditory, or bimodal. We initially trained cats to look toward the location of briefly presented single visual or single auditory targets that were extinguished before the initiation of eye movements. Following training, we monitored eye movements during and after the presentation of double targets, either two visual, two auditory, or bimodal, that were at disparate spatial locations. Cats made saccadic eye movements to positions that ranged between the location of the two targets. If the eye position at the start of a saccade was near the mid point of the targets, cats were less likely to initiate a saccade, and saccadic latencies were longer, compared to when starting eye position was at a distance from this location. These behavioral results are consistent with the hypothesis that the neural representations of briefly presented targets are combined and treated as a unitary, low resolution stimulus from which an orienting motor program is derived. The similarity of responses to double visual, double auditory, and bimodal stimuli suggests that a common sensorimotor mechanism applies within and between these sensory modalities.
Selective Interference with the Representation of Size in the Human by Direct Cortical Electrical Stimulation
Authors: Hart John , Lesser Ronald P. , Gordon Barry 
Published: February 2008

Abstract
A specific category in human cognition, size representation, was disrupted by the application of cortical electrical interference through a recently modified technique involving implantation of indwelling subdural electrode arrays. When subjected to electrical stimulation at a specific site, the subject was unable to access size information when questioned verbally, but showed no deficit if the size discrimination was presented visually. Verbal questions about size were answered correctly when the patient was not subjected to cortical interference. Other measures of verbal and visual comprehension for the categories of color, shape, orientation, movement, texture, and structure, tested under cortical interference, were normal. This clear-cut distinction between verbal and visual access to information about size, shown by a reversible block at a known and anatomically circumscribed site, provides further evidence that higher order neural processing is categorically represented.
Human Cerebral Cortex: Localization, Parcellation, and Morphometry with Magnetic Resonance Imaging
Authors: Rademacher J. , Galaburda A. M. , Kennedy D. N. , Filipek P. A. , Caviness V. S. 
Published: February 2008

Abstract
We describe a system of parcellation of the human brain that is based on the functional anatomy of the cerebral cortex and that is applied to the analysis of magnetic resonance images. This system is designed to support investigations of hemispheric asymmetries and quantitative lesion localization studies in cognitive neuroscience. The system of cortical subdivision is a neural systems oriented model that approximates subdivisions supported by previous architectonic and functional analyses. It is based primarily on boundaries determined by "limiting fissures." It is completed by a set of coronal planes, keyed to visible anatomic landmarks, which "close" the borders of the parcellation subdivisions. The method depends on computational reconstruction of the primary image data in multiple planes so as to allow the observed pattern of limiting fissures in a given brain to be digitized. In this presentation, the method is applied in order to define the surface anatomy of the cerebral hemispheres in a normal subject. Volumetric measurements of individual cortical regions are compared as hemispheric percentiles to areal perceniiles derived from the analysis of Jouandet et al. (1989), a conceptually related though methodologically different approach. We specifically address the approach to the study of interhemispheric differences and interindividual variations in cortical anatomy.