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Visual Attention (visual + attention)
Kinds of Visual Attention Selected AbstractsNEUROPHYSIOLOGY OF VISUAL ATTENTION AND VISUAL SHORT-TERM MEMORY: FROM N2PC TO SPCNPSYCHOPHYSIOLOGY, Issue 2006Article first published online: 7 AUG 200 No abstract is available for this article. [source] The Effects of Graded Occlusion on Manual Search and Visual Attention in 5- to 8-Month-Old InfantsINFANCY, Issue 3 2000Jeanne L. Shinskey Young infants may be limited in searching for hidden objects because they lack the means-end motor skill to lift occluders from objects. This account was investigated by presenting 5- to 8-month-old infants with objects hidden behind transparent, semitransparent, and opaque curtains. If a means,end deficit explains search limitations, then infants should search no more for an object behind a transparent curtain than for objects behind semitransparent or opaque curtains. However, level of occlusion had a significant effect on manual search and visual attention. Infants retrieved and contacted the object more, contacted the curtain more, and looked away less with the transparent curtain than with the semi transparent or opaque curtains. Adding a time delay before allowing search and presenting a distraction after occlusion further depressed infants' behavior. The findings fail to support the means,end deficit hypothesis, but are consistent with the account that young infants lack object permanence. [source] Effects of attention and arousal on early responses in striate cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2005Vahe Poghosyan Abstract Humans employ attention to facilitate perception of relevant stimuli. Visual attention can bias the selection of a location in the visual field, a whole visual object or any visual feature of an object. Attention draws on both current behavioral goals and/or the saliency of physical attributes of a stimulus, and it influences activity of different brain regions at different latencies. Attentional effect in the striate and extrastriate cortices has been the subject of intense research interest in many recent studies. The consensus emerging from them places the first attentional effects in extrastriate areas, which in turn modulate activity of V1 at later latencies. In this view attention influences activity in striate cortex some 150 ms after stimulus onset. Here we use magnetoencephalography to compare brain responses to foveally presented identical stimuli under the conditions of passive viewing, when the stimuli are irrelevant to the subject and under an active GO/NOGO task, when the stimuli are cues instructing the subject to make or inhibit movement of his/her left or right index finger. The earliest striate activity was identified 40,45 ms after stimulus onset, and it was identical in passive and active conditions. Later striate response starting at about 70 ms and reaching a peak at about 100 ms showed a strong attentional modulation. Even before the striate cortex, activity of the right inferior parietal lobule was modulated by attention, suggesting this region as a candidate for mediating attentional signals to the striate cortex. [source] Mathematical skills in Williams syndrome: Insight into the importance of underlying representationsDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 1 2009Kirsten O'Hearn Abstract Williams syndrome (WS) is a developmental disorder characterized by relatively spared verbal skills and severe visuospatial deficits. Serious impairments in mathematics have also been reported. This article reviews the evidence on mathematical ability in WS, focusing on the integrity and developmental path of two fundamental representations, namely those that support judgments of "how much" (i.e., magnitude) and "how many" (i.e., number of objects). Studies on magnitude or "number line" representation in WS suggest that this core aspect of mathematical ability, is atypical in WS throughout development, causing differences on some but not all aspects of math. Studies on the representation of small numbers of objects in WS are also reviewed, given the proposed links between this type of representation and early number skills such as counting. In WS, representation appears to be relatively typical in infancy but limitations become evident by maturity, suggesting a truncated developmental trajectory. The math deficits in WS are consistent with neurological data indicating decreased gray matter and hypoactivation in parietal areas in WS, as these areas are implicated in mathematical processing as well as visuospatial abilities and visual attention. In spite of their deficits in core mathematical representations, people with WS can learn many mathematical skills and show some strengths, such as reading numbers. Thus individuals with WS may be able to take advantage of their relatively strong verbal skills when learning some mathematical tasks. The uneven mathematical abilities found in persons with WS provide insight into not only appropriate remediation for this developmental disorder but also into the precursors of mathematical ability, their neural substrates, and their developmental importance. © 2009 Wiley-Liss, Inc. Dev Disabil Res Rev 2009;15:11,20. [source] Neuropsychological effects of hyperbaric oxygen therapy in cerebral palsyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 7 2002Paule Hardy We conducted a double-blind placebo study to investigate the claim that hyperbaric oxygen treatment (HBO2) improves the cognitive status of children with cerebral palsy (CP). Of 111 children diagnosed with CP (aged 4 to 12 years), only 75 were suitable for neuropsychological testing, assessing attention, working memory, processing speed, and psychosocial functioning. The children received 40 sessions of HBO2 or sham treatment over a 2-month period. Children in the active treatment group were exposed for 1 hour to 100% oxygen at 1.75 atmospheres absolute (ATA), whereas those in the sham group received only air at 1.3 ATA. Children in both groups showed better self-control and significant improvements in auditory attention and visual working memory compared with the baseline. However, no statistical difference was found between the two treatments. Furthermore, the sham group improved significantly on eight dimensions of the Conners'Parent Rating Scale, whereas the active treatment group improved only on one dimension. Most of these positive changes persisted for 3 months. No improvements were observed in either group for verbal span, visual attention, or processing speed. [source] Testing neural models of the development of infant visual attentionDEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2002John E. Richards Abstract Several models of the development of infant visual attention have used information about neural development. Most of these models have been based on nonhuman animal studies and have relied on indirect measures of neural development in human infants. This article discusses methods for studying a "neurodevelopmental" model of infant visual attention using indirect and direct measures of cortical activity. We concentrate on the effect of attention on eye movement control and show how animal-based models, indirect measurement in human infants, and direct measurement of brain activity inform this model. © 2002 Wiley Periodicals, Inc. Dev Psychobiol 40: 226,236, 2002. DOI 10.1002/dev.10029 [source] Neuropsychological functioning in older people with Type 2 diabetes: the effect of controlling for confounding factorsDIABETIC MEDICINE, Issue 4 2002K. G. Asimakopoulou Abstract Aims and methods Neuropsychological functioning was examined in a group of 33 older (mean age 62.40 ± 9.62 years) people with Type 2 diabetes (Group 1) and 33 non-diabetic participants matched with Group 1 on age, sex, premorbid intelligence and presence of hypertension and cardio/cerebrovascular conditions (Group 2). Results Data statistically corrected for confounding factors obtained from the diabetic group were compared with the matched control group. The results suggested small cognitive deficits in diabetic people's verbal memory and mental flexibility (Logical Memory A and SS7). No differences were seen between the two samples in simple and complex visuomotor attention, sustained complex visual attention, attention efficiency, mental double tracking, implicit memory, and self-reported memory problems. Conclusions These findings indicate minimal cognitive impairment in relatively uncomplicated Type 2 diabetes and demonstrate the importance of control and matching for confounding factors. [source] The contribution of phonological awareness and visual attention in early reading and spellingDYSLEXIA, Issue 1 2007Monique Plaza Abstract We examined the development of phonological processing, naming speed, and visual attention in kindergarten and addressed the question of their contribution to reading and spelling in grade 1. Seventy five French-speaking children were administered seven tasks at the two phases of the study, and reading and spelling were assessed in grade 1. The major findings revealed that syllable awareness and visual attention were the most important predictors of early reading and spelling, and confirm the influence of naming speed and phoneme awareness on specific skills. These observations strongly suggest that written language acquisition relies on linguistic, perceptual and cognitive cross-modal skills and highlight the need for diversifying written language measures and analyzing their specific predictors. Copyright © 2006 John Wiley & Sons, Ltd. [source] An evaluation of a visual biofeedback intervention in dyslexic adultsDYSLEXIA, Issue 1 2005Elizabeth Liddle Abstract A prototype of a biofeedback system designed to treat dyslexia by improving heart-rate variability was evaluated in a single blind study of dyslexic adults. Treatment consisted of four 15 minute exposures to a visual display synchronized with either the participant's own cardiac cycle (intervention condition), or of a synthesized cardiac cycle (placebo condition). Repeated measures were made of picture naming speed, single word reading speed and accuracy, copying speed, heart-rate variability and performance on a lateralized visual temporal order judgement task. Small but significant improvements were found in reading and naming speed in the treatment group relative to the placebo group. No significant improvements were found in unspeeded reading measures. Results from heart-rate measures indicated that treatment had effected a shift in the ratio between parameters reflecting the influence of the sympathetic and parasympathetic autonomic nervous systems (ANS), respectively, in favour of the parasympathetic. In the temporal order judgement task, participants who received treatment showed a reduced level of overall improvement relative to that seen in those who received placebo, coupled with evidence of a shift in visual attention from left to right hemifield in their pattern of performance. The results are interpreted as indicating that the treatment induces a shift in autonomic balance in favour of the parasympathetic ANS, and that this shift is also reflected in increased efficiency of left cerebral hemisphere circuits implicated in the perceptual-motor processes required for naming and reading fluency. Conversely, it is also reflected in lower spatial awareness of peripheral visual stimuli, particularly those presented to left hemifield. Copyright © 2004 John Wiley & Sons, Ltd. [source] Behavior selection of mobile robot based on integration of multimodal informationELECTRICAL ENGINEERING IN JAPAN, Issue 2 2007Bin Chen Abstract Recently, biologically inspired robots have been developed to acquire the capacity for directing visual attention to salient stimulus generated from the audiovisual environment. For the purpose of realizing this behavior, a general method is to calculate saliency maps to represent how much the external information attracts the robot's visual attention, where the audiovisual information and robot's motion status should be involved. In this paper, we represent a visual attention model where three modalities,audio information, visual information, and robot's motor status,are considered, because previous research has not considered all of them. First, we introduce a 2D density map, on which the value denotes how much the robot pays attention to each spatial location. Then we model the attention density using a Bayesian network where the robot's motion statuses are involved. Next, the information from both audio and visual modalities is integrated with the attention density map in integrate-fire neurons. The robot can direct its attention to the locations where the integrate-fire neurons are fired. Finally, the visual attention model is applied to make the robot select the visual information from the environment, and react to the content selected. Experimental results show that it is possible for robots to acquire the visual information related to their behaviors by using the attention model considering motion statuses. The robot can select its behaviors to adapt to the dynamic environment as well as to switch to another task according to the recognition results of visual attention. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 39,48, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20335 [source] Prepare for conflict: EEG correlates of the anticipation of target competition during overt and covert shifts of visual attentionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2010Simon P. Kelly Abstract When preparing to make a saccadic eye movement in a cued direction, perception of stimuli at the target location is enhanced, just as it is when attention is covertly deployed there. Accordingly, the timing and anatomical sources of preparatory brain activity accompanying shifts of covert attention and saccade preparation tend to exhibit a large degree of overlap. However, there is evidence that preparatory processes are modulated by the foreknowledge of visual distractor competition during covert attention, and it is unknown whether eye movement preparation undergoes equivalent modulation. Here we examine preparatory processes in the electroencephalogram of human participants during four blocked versions of a spatial cueing task, requiring either covert detection or saccade execution, and either containing a distractor or not. As in previous work, a typical pattern of spatially selective occipital, parietal and frontal activity was seen in all task versions. However, whereas distractor presence called on an enhancement of spatially selective visual cortical modulation during covert attention, it instead called on increased activity over frontomedial oculomotor areas in the case of overt saccade preparation. We conclude that, although advance orienting signals may be similar in character during overt and covert conditions, the pattern by which these signals are modulated to ameliorate the behavioral costs of distractor competition is highly distinct, pointing to a degree of separability between the overt and covert systems. [source] Detection of unexpected events during spatial navigation in humans: bottom-up attentional system and neural mechanismsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2008Giuseppe Iaria Abstract Navigation is a complex cognitive ability requiring the processing and integration of several different types of information extracted from the environment. While navigating, however, an unexpected event may suddenly occur, which individuals are required to detect promptly in order to apply an appropriate behavioural response. The alerting mechanism that is integral to the detection of unexpected events is referred to as the bottom-up attentional system. Using event-related functional magnetic resonance imaging, we investigated the neural basis of bottom-up detection of unexpected events while individuals moved within a virtual environment. We identified activation within a right fronto-temporo-parietal network in response to unexpected events while navigating in this virtual environment. Furthermore, when an unexpected event requires an adjusted behavioural response, a region of the right ventrolateral pre-frontal cortex (areas 45 and 47/12) is selectively activated. Our data replicate earlier findings on the neural mechanisms underlying visual attention and extend these findings to the more complex real-life ability of spatial navigation, thereby suggesting that these neural mechanisms subserve the bottom-up attentional systems that are crucial for effective locomotion in real surroundings. [source] Adult gaze influences infant attention and object processing: implications for cognitive neuroscienceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2005Vincent M. Reid Abstract Infants follow others' gaze toward external objects from early in ontogeny, but whether they use others' gaze in processing information about objects remains unknown. In Experiment 1, 4-month-old infants viewed a video presentation of an adult gazing toward one of two objects. When presented with the same objects alone a second time, infants looked reliably less at the object to which the adult had directly gazed (cued object). This suggests that the uncued object was perceived as more novel than the object previously cued by the adult's gaze. In Experiment 2, adult gaze was not directed towards any object. In this control experiment, infants looked at both objects equally in the test phase. These findings show that adult eye gaze biases infant visual attention and information processing. Implications of the paradigm for cognitive neuroscience are presented and the results are discussed in terms of neural structures and change over ontogeny. [source] The role of the magnocellular pathway in serial deployment of visual attentionEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 8 2004Alicia Cheng Abstract Normal human visual function often demands detection of a target among a number of other objects cluttering the scene, such as when searching for a known face in a crowd. In these and similar tasks, the search performed is a serial one, with an attentional spotlight scanning the objects of the scene. We have investigated whether one of the afferent channels in vision, the colour-blind magnocellular pathway, is essential in such serial searches. We did this by using items that were isoluminant with the background but of a different colour, for which the magnocellular cells would be blind. The search in these conditions required much longer reaction times than when even a very small luminance contrast (2%) was added to the items. Because such luminance contrasts can be detected only by magnocellular cells and not by neurons of the other channels (parvocellular and koniocellular), the magnocellular pathway appears vitally important for serial search. In contrast, in a feature search task, which does not require allocation of attentional resources, the search was as efficient with isoluminance as when luminance contrast was added to the items. [source] Dissociation between top-down attentional control and the time course of visual attention as measured by attentional dwell time in patients with mild cognitive impairmentEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2003Richard J. Perry Abstract Studies of the time course of visual attention have identified a temporary functional blindness to the second of sequentially presented stimuli in that the attentional cost of attending to one visual stimulus may lead to impairments in identifying a second stimulus presented within 500 ms of the first. This phenomenon is known as the attentional blink or attentional dwell time. The neural correlates of the attentional blink and its relationship to mechanisms that control attention are unknown. To examine this relationship we tested healthy controls and subjects in the preclinical stage of Alzheimer's disease, known as mild cognitive impairment (MCI), on a paradigm which affords quantification of both the attentional blink and the top-down control of attention. When subjects were asked to identify both a number and a letter that were rapidly and sequentially presented on a visual display, the detrimental effect that identifying the first stimulus had on the ability to identify the second served as a measure of the attentional blink. When asked to identify only one of the two stimuli, the ability to ignore the first stimulus was a function of their top-down attentional control. The MCI subjects demonstrated a normal attentional dwell time but in contrast they showed impaired top-down attentional control within the same paradigm. This dissociation suggests that these two aspects of visual attention are subserved by different neural systems. The possible neural correlates of these two attentional functions are discussed. [source] Involvement of the human frontal eye field and multiple parietal areas in covert visual selection during conjunction searchEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 9 2000Tobias Donner Abstract Searching for a target object in a cluttered visual scene requires active visual attention if the target differs from distractors not by elementary visual features but rather by a feature conjunction. We used functional magnetic resonance imaging (fMRI) in human subjects to investigate the functional neuroanatomy of attentional mechanisms employed during conjunction search. In the experimental condition, subjects searched for a target defined by a conjunction of colour and orientation. In the baseline condition, subjects searched for a uniquely coloured target, regardless of its orientation. Eye movement recordings outside the scanner verified subjects' ability to maintain fixation during search. Reaction times indicated that the experimental condition was attentionally more demanding than the baseline condition. Differential activations between conditions were therefore ascribed to top-down modulation of neural activity. The frontal eye field, the ventral precentral sulcus and the following posterior parietal regions were consistently activated: (i) the postcentral sulcus; (ii) the posterior; and (iii) the anterior part of the intraparietal sulcus; and (iv) the junction of the intraparietal with the transverse occipital sulcus. Parietal regions were spatially distinct and displayed differential amplitudes of signal increase with a maximal amplitude in the posterior intraparietal sulcus. Less consistent activation was found in the lateral fusiform gyrus. These results suggest an involvement of the human frontal eye field in covert visual selection of potential targets during search. These results also provide evidence for a subdivision of posterior parietal cortex in multiple areas participating in covert visual selection, with a major contribution of the posterior intraparietal sulcus. [source] Neural Correlates of Encoding Predict Infants' Memory in the Paired-Comparison ProcedureINFANCY, Issue 3 2010Kelly A. Snyder The present study used event-related potentials (ERPs) to monitor infant brain activity during the initial encoding of a previously novel visual stimulus, and examined whether ERP measures of encoding predicted infants' subsequent performance on a visual memory task (i.e., the paired-comparison task). A late slow wave component of the ERP measured at encoding predicted infants' immediate performance in the paired-comparison task: amplitude of the late slow wave at right-central and temporal leads decreased with stimulus repetition, and greater decreases at right-anterior-temporal leads during encoding were associated with better memory performance at test. By contrast, neither the amplitude nor latency of the negative central (Nc) component predicted infants' subsequent performance in the paired-comparison task. These findings are discussed with respect to a biased competition model of visual attention and memory. [source] Child, Caregiver, and Temperament Contributions to Infant Joint AttentionINFANCY, Issue 4 2003Amy Vaughan Little is known about variables that may contribute to individual differences in infant joint attention, or the coordination of visual attention with a social partner. Therefore, this study examined the contributions of caregiver behavior and temperament to infant joint attention development between 9 and 12 months. Data were collected from 57 infants using a caregiver,infant paradigm, an infant,tester paradigm, and a parent report of infant temperament. Nine-month measures of caregiver scaffolding and infant initiating joint attention (IJA) with testers were significantly related to 12-month infant IJA with testers. A temperament measure of positive emotional reactivity was related to 9-month IJA, and a measure of negative emotional reactivity was related to 12-month IJA. Temperament and caregiver scaffolding measures, however, were not associated with the development of infant responding to joint attention. These results further the understanding of the multiple processes that contribute to joint attention development in infancy, and support the hypothesis that initiating and responding measures tap different aspects of joint attention development. [source] Individual Differences in Infants' Recognition of Briefly Presented Visual StimuliINFANCY, Issue 3 2001Janet E. Frick Infants' recognition memory has been shown to be related to individual differences in look duration and level of heart period variability. This study examined the effect of individual differences in these 2 measures on infants' recognition of briefly presented visual stimuli using a paired-comparison recognition-memory paradigm. A sample of 35 full-term infants was studied longitudinally at 14, 20, and 26 weeks of age. Recognition memory for briefly presented stimuli was tested in 6 experimental conditions, with delays corresponding to different heart-rate-defined phases of attention. The 20-and 26-week-old infants, and infants with high levels of heart period variability, generally showed more evidence of recognition memory for briefly presented visual stimuli. Greater evidence of recognition memory was observed when stimuli were presented during sustained attention. Infants with more mature baseline physiological responses show greater evidence of recognition memory, and stimulus and procedural factors may be more important for the study of individual differences in infant visual attention than has previously been suggested. [source] The Effects of Graded Occlusion on Manual Search and Visual Attention in 5- to 8-Month-Old InfantsINFANCY, Issue 3 2000Jeanne L. Shinskey Young infants may be limited in searching for hidden objects because they lack the means-end motor skill to lift occluders from objects. This account was investigated by presenting 5- to 8-month-old infants with objects hidden behind transparent, semitransparent, and opaque curtains. If a means,end deficit explains search limitations, then infants should search no more for an object behind a transparent curtain than for objects behind semitransparent or opaque curtains. However, level of occlusion had a significant effect on manual search and visual attention. Infants retrieved and contacted the object more, contacted the curtain more, and looked away less with the transparent curtain than with the semi transparent or opaque curtains. Adding a time delay before allowing search and presenting a distraction after occlusion further depressed infants' behavior. The findings fail to support the means,end deficit hypothesis, but are consistent with the account that young infants lack object permanence. [source] Posture, muscular tone and visual attention in 5 month-old infantsINFANT AND CHILD DEVELOPMENT, Issue 4 2002Carole Lefèvre Abstract The present paper aims at studying the relationships between posture, muscle tone and visual attention in 5 month-old infants. To this end, a specially designed seating arrangement made it possible to vary posture while keeping constant the spatial relationship between eyes and stimuli. Five month-olds were placed in the reclining position (30°) or in a more erect position (60°). The more erect the posture, the more difficult it should be for the infant to maintain a straight body axis. Muscle tone was evaluated, and infants distinguished in terms of whether they were hypertonic or hypotonic. It was hypothesised that in a more erect position hypotonic children, who experience more difficulties in maintaining posture, should organise their visual exploration in ways different from those considered to be hypertonic. To test it, pairs of three-dimensional stimuli were presented in the distal visual field for one group (N=48) and in the proximal visual field in another group (N=32) for 2 min in each posture. The dynamical organisation of attention was evaluated through the number and duration of fixations on each target, the number of shifts from one target to the other (alternations) and the number of repetitions (back to the previous target). Results showed that visual behaviour was significantly affected by the distance at which stimuli were presented. Infants spent more time in visual exploration when the object was within reach than when it was out of reach. Although posture was shown to play a role in the organisation of visual exploration, no link with muscle tone was found, a surprising result which is discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source] Infant visual habituation and parental psychological distressINFANT MENTAL HEALTH JOURNAL, Issue 4 2001David P. Laplante Research is equivocal concerning the relationship between parental psychological distress and infant cognitive functioning. Four potential limitations of the literature are addressed: reliance on mothers' but not fathers' psychological distress, use of categorical measures of psychological distress, use of standardized measures of infant cognitive functioning, and failure to take into account potential gender differences. Ninety-nine twin pairs and both their mothers and fathers were assessed. Infants cognitive functioning was assessed using an infant-controlled habituation,recovery,dishabituation task. Maternal and paternal psychological distress was assessed using the Symptom Check List-90-Revised. No gender differences were obtained for infant visual information-processing abilities or parental psychological distress. Maternal and paternal psychological distress was related to female visual encoding abilities only. It was concluded that parental psychological distress might degrade parent,infant interactions. Characteristics of girls when faced with parents exhibiting psychiatric difficulties may exacerbate difficulties of parent,infant interactions, thereby hindering the full development of cognitive abilities involved in the process of habituation. A need exists to examine the relationship between parental psychological distress and infant visual attention separately for girls and boys. ©2001 Michigan Association for Infant Mental Health. [source] Visuospatial impairment in dementia with Lewy bodies and Alzheimer's disease: a process analysis approachINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2003Martine Simard Abstract Background Reports of differential impairments on visual-construction tasks in dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are sometimes controversial, whereas visual-perceptual data are lacking. The existence of different clinical sub-groups of DLB has been hypothesized to explain the discrepancies among the cognitive results. The goal of this study was to compare the visual-perceptual performance of subjects with DLB with predominant psychosis, DLB with predominant parkinsonian features and AD. Methods This is a cross-sectional neuropsychological study with between diagnostic group comparisons. The Benton Judgement Line Orientation (BJLO) test was administered to four DLB patients with predominant psychosis (DLB-psy), four DLB subjects with predominant parkinsonian features (DLB-PD), and 13 patients with AD. An analysis of error types was applied to the results of the BJLO with QO1, QO2, QO3, QO4 (visual attention) errors, as well as VH, IQO, IQOV, and IQOH (visual-spatial perception) errors. Results A MANOVA showed significant differences between the DLB, and AD groups on the number of VH (F,=,6.049, df,=,1,19, p,=,0.024), IQOH (F,=,4.645, df,=,1,19, p,=,0.044) and QO1 (F,=,4.491, df,=,1,19, p,=,0.047) errors, but no difference on the total score of the BJLO. Another MANOVA and post hoc Student,Newman,Keuls analyses demonstrated that the DLB-psy sub-group made significantly more VH and IQOH errors than AD and the DLB-PD subjects. Conclusions Subjects with DLB and psychosis have more severe visual-perception (VH errors) impairments than subjects with DLB and predominant parkinsonian features, and AD subjects. Copyright © 2003 John Wiley & Sons, Ltd. [source] Timing of Thyroid Hormone Action in the Developing Brain: Clinical Observations and Experimental FindingsJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2004R. T. Zoeller Abstract The original concept of the critical period of thyroid hormone (TH) action on brain development was proposed to identify the postnatal period during which TH supplement must be provided to a child with congenital hypothyroidism to prevent mental retardation. As neuropsychological tools have become more sensitive, it has become apparent that even mild TH insufficiency in humans can produce measurable deficits in very specific neuropsychological functions, and that the specific consequences of TH deficiency depends on the precise developmental timing of the deficiency. Models of maternal hypothyroidism, hypothyroxinaemia and congential hyperthyroidism have provided these insights. If the TH deficiency occurs early in pregnancy, the offspring display problems in visual attention, visual processing (i.e. acuity and strabismus) and gross motor skills. If it occurs later in pregnancy, children are at additional risk of subnormal visual (i.e. contrast sensitivity) and visuospatial skills, as well as slower response speeds and fine motor deficits. Finally, if TH insufficiency occurs after birth, language and memory skills are most predominantly affected. Although the experimental literature lags behind clinical studies in providing a mechanistic explanation for each of these observations, recent studies confirm that the specific action of TH on brain development depends upon developmental timing, and studies informing us about molecular mechanisms of TH action are generating hypotheses concerning possible mechanisms to account for these pleiotropic actions. [source] Effectiveness of using a computer to improve attention to visual analysis activities of five preschool children with disabilitiesOCCUPATIONAL THERAPY INTERNATIONAL, Issue 1 2000Maria Del Pilar Cardona Abstract This study used a single-subject reversal research design to examine the effectiveness of using a computer to improve attention to visual analysis activities in five preschool children with disabilities in a special education programme. Baseline levels of attention to task behaviours were measured during the performance of fine motor tabletop visual analysis activities of matching, requiring shape recognition, counting, free drawing, and size and colour discrimination. During the intervention phase, computer-based visual analysis activities were introduced. Results suggest that each child's attention to task performance improved during the computer-based activities, when measured by the number of distractions, although sitting tolerance and visual attention to the task did not change. The findings of this study, although limited to five participants with developmental disabilities, suggest that the students were interested and motivated to engage in computer-based activities. More research is needed to examine a longer intervention phase and the effectiveness of computer-based intervention in natural settings such as a classroom. Copyright © 2000 Whurr Publishers Ltd. [source] Dimension-based attention modulates early visual processingPSYCHOPHYSIOLOGY, Issue 5 2010Klaus Gramann Abstract Target selection can be based on spatial or dimensional/featural mechanisms operating in a location-independent manner. We investigated whether dimension-based attention affects processing in early visual stages. Subjects searched for a singleton target among an 8-item array, with the search display preceded by an identical cue array with a dimensionally non-predictive, but spatially predictive singleton. Reaction times (RTs) were increased for changes in the target-defining dimension but not for featural changes within a dimension. This RT effect was mirrored by modulations of the P1 and anterior transition N2 (tN2). Current density reconstructions revealed increased activity in dorsal occipital cortex and decreased activity in left frontopolar cortex owing to repeated dimensional pop-out identities. These findings strengthen dimension-based theories of visual attention by indicating dimension-, rather than feature-, specific influences within the first 110 ms of visual processing. [source] Flexibility in the use of requesting gestures in squirrel monkeys (Saimiri sciureus)AMERICAN JOURNAL OF PRIMATOLOGY, Issue 8 2010James R. Anderson Abstract Three squirrel monkeys, trained to make a requesting gesture, were tested in the presence of a human assistant whose visual attention varied across trials. When food was available in one dish and an empty dish was nearby, the monkeys pointed overwhelmingly toward the former, regardless of where the assistant was looking. Looking at the assistant while pointing ("monitoring") peaked when she looked at them and when she attempted to engage them in joint attention. When only one dish was present, the monkeys refrained from gesturing if it was empty and if no assistant was present. They gestured more when the assistant made eye contact with them. Furthermore, when the assistant's focus of attention switched from the dish or the ceiling to the monkeys, the latter resumed pointing and increased their monitoring of the assistant. This is the first demonstration of such flexible use of an intentionally communicative requesting gesture in New World monkeys. Am. J. Primatol. 72:707,714, 2010. © 2010 Wiley-Liss, Inc. [source] Unbroken mirror neurons in autism spectrum disordersTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 9 2010Yang-Teng Fan Background:, The ,broken mirror' theory of autism, which proposes that a dysfunction of the human mirror neuron system (MNS) is responsible for the core social and cognitive deficits in individuals with autism spectrum disorders (ASD), has received considerable attention despite weak empirical evidence. Methods:, In this electroencephalographic study, we examined mu suppression, as an indicator of sensorimotor resonance, concurrent with oculomotor performance while individuals (n = 20) with ASD and control participants (n = 20) either executed hand actions or observed hand actions or a moving dot. No difference in visual attention between groups was found as indicated by fixation duration and normalized fixation number on the presented stimuli. Results:, The mu suppression over the sensorimotor cortex was significantly affected by experimental conditions, but not by group membership, nor by the interaction between groups and conditions. Individuals with ASD, similar to the controls, exhibited stronger mu suppression when watching hand actions relative to a moving dot. Notably, participants with ASD failed to imitate the observed actions while their mu suppression indicating the MNS activity was intact. In addition, the mu suppression during the observation of hand actions was positively associated with the communication competence of individuals with ASD. Conclusion:, Our study clearly challenges the broken mirror theory of autism. The functioning of the mirror neuron system might be preserved in individuals with ASD to a certain degree. Less mu suppression to action observation coupled with more communicational severity can reflect the symptom heterogeneity of ASD. Additional research needs to be done, and more caution should be used when reaching out to the media. [source] Orienting of visual attention among persons with autism spectrum disorders: reading versus responding to symbolic cuesTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 7 2009Oriane Landry Background:, Are persons with autism spectrum disorders (ASD) slower than typically developing individuals to read the meaning of a symbolic cue in a visual orienting paradigm? Methods:, Participants with ASD (n = 18) and performance mental age (PMA) matched typically developing children (n = 16) completed two endogenous orienting conditions in which the cue exposure time and response preparation time were manipulated within a consistent series of cue-target stimulus onset asynchronies (SOAs). Results:, Participants with ASD displayed facilitation effects at all SOAs, whereas typically developing children displayed facilitation effects only at shorter SOAs. The magnitude of the facilitation effect was greater for the group with ASD at 400ms SOA. Both groups showed similar effects of condition, with similar patterns of facilitation in both conditions. Conclusion:, Persons with ASD were not slower to read the symbolic cue, as the effect was elicited by brief cues within longer SOAs before target onset. The participants with ASD were also less efficient in using the predictability of the cues to guide responding. The difficulties of participants with ASD on endogenous orienting occur at the response selection level, not the perceptual level. [source] Visual orienting in the early broader autism phenotype: disengagement and facilitationTHE JOURNAL OF CHILD PSYCHOLOGY AND PSYCHIATRY AND ALLIED DISCIPLINES, Issue 5 2009Mayada Elsabbagh Background:, Recent studies of infant siblings of children diagnosed with autism have allowed for a prospective approach to examine the emergence of symptoms and revealed behavioral differences in the broader autism phenotype within the early years. In the current study we focused on a set of functions associated with visual attention, previously reported to be atypical in autism. Method:, We compared performance of a group of 9,10-month-old infant siblings of children with autism to a control group with no family history of autism on the ,gap-overlap task', which measures the cost of disengaging from a central stimulus in order to fixate a peripheral one. Two measures were derived on the basis of infants' saccadic reaction times. The first is the Disengagement effect, which measures the efficiency of disengaging from a central stimulus to orient to a peripheral one. The second was a Facilitation effect, which arises when the infant is cued by a temporal gap preceding the onset of the peripheral stimulus, and would orient faster after its onset. Results and conclusion:, Infant siblings of children with autism showed longer Disengagement latencies as well as less Facilitation relative to the control group. The findings are discussed in relation to how differences in visual attention may relate to characteristics observed in autism and the broader phenotype. [source] | |||||||||||||||||||