首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Parasympathetic heart rate regulation was studied in full-term (FT) and very preterm (VPT) infants at the corrected age of 5 months during endogenous and exogenous sustained attention. Cardiac interval duration and the respiratory sinus arrhythmia (RSA) were used as indices of parasympathetic regulation of heart activity during infants’ sustained attention to a new visual stimulus (exogenous attention) and anticipatory attention to repeatedly appearing and disappearing stimuli in the visual expectation paradigm (endogenous attention). The psychomotor development and behavior regulation were assessed using the Bayley Scales of Infant Development, and the clinical risk was scored on the Ballard scale. A shift of attention state affected the RSA only in the FT infants. The endogenous attention was associated with a relatively high RSA level, with the higher RSA levels being significantly correlated with the Bayley Behavior Rating Scale scores. At the age of 5 months, the degree of clinical risk in the VPT infants was not correlated with specific features of parasympathetic regulation. The results are discussed in terms of the concepts of physiological mechanisms of exogenous and endogenous attention in infants. The central regulation of the autonomic functions during a shift of attention state is less efficient in healthy VPT infants as compared to their FT peers. The RSA reactivity can be a more sensitive indicator of CNS regulatory disorders than the standard indices of clinical risk.  相似文献   

2.
Although it is well known that attention to a visual or auditory stimulus can enhance its perception, less is known concerning the effects of attention on the perception of natural tactile stimuli. The present study was conducted to examine the magnitude of the effect of cross-modal manipulations of attention in human subjects on the detection of weak, low-frequency vibrotactile stimuli delivered to the glabrous skin of the finger pad of the right index finger via an Optacon. Three suprathreshold vibrotactile arrays (40 Hz), varying in the number of activated pegs and hence the area of skin stimulated, were used. Subjects were trained to detect the occurrence of vibrotactile or visual stimuli and to respond by pressing a foot pedal as quickly as possible thereafter. Two instructional lights were used to cue the subjects as to which stimulus modality they should attend, in three experimental conditions. In the first cue condition, the forthcoming stimulus modality was indicated by the illumination of its associated light. In the second cue condition, both instructional lights were illuminated, and the subjects were asked to divide their attention equally between the two modalities. In the third cue condition, the stimulus modality was falsely indicated by the illumination of the cue not associated with the stimulus to be presented. Reaction times (RTs) were calculated for each trial. For each modality, tactile and visual, the RTs varied significantly with the cue condition, with the mean RT changing in a graded manner across the experimental conditions (being shortest for the correctly cued condition, intermediate for the neutrally cued condition, and longest for the incorrectly cued condition.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

3.
Sensory flooding, particularly during auditory stimulation, is a common problem for patients with schizophrenia. The functional consequences of this impairment during cross-modal attention tasks, however, are unclear. The purpose of this study was to examine how auditory distraction differentially affects task-associated response during visual attention in patients and healthy controls. To that end, 21 outpatients with schizophrenia and 23 healthy comparison subjects performed a visual attention task in the presence or absence of distracting, environmentally relevant “urban” noise while undergoing functional magnetic resonance imaging at 3T. The task had two conditions (difficult and easy); task-related neural activity was defined as difficult – easy. During task performance, a significant distraction (noise or silence) by group (patient or control) interaction was observed in the left dorsolateral prefrontal cortex, right hippocampus, left temporoparietal junction, and right fusiform gyrus, with patients showing relative hypoactivation during noise compared to controls. In patients, the ability to recruit the dorsolateral prefrontal cortex during the task in noise was negatively correlated with the effect of noise on reaction time. Clinically, the ability to recruit the fusiform gyrus during the task in noise was negatively correlated with SANS affective flattening score, and hippocampal recruitment during the task in noise was positively correlated with global functioning. In conclusion, schizophrenia may be associated with abnormalities in neural response during visual attention tasks in the presence of cross-modal noise distraction. These response differences may predict global functioning in the illness, and may serve as a biomarker for therapeutic development.  相似文献   

4.
Temporal information is often contained in multi-sensory stimuli, but it is currently unknown how the brain combines e.g. visual and auditory cues into a coherent percept of time. The existing studies of cross-modal time perception mainly support the "modality appropriateness hypothesis", i.e. the domination of auditory temporal cues over visual ones because of the higher precision of audition for time perception. However, these studies suffer from methodical problems and conflicting results. We introduce a novel experimental paradigm to examine cross-modal time perception by combining an auditory time perception task with a visually guided motor task, requiring participants to follow an elliptic movement on a screen with a robotic manipulandum. We find that subjective duration is distorted according to the speed of visually observed movement: The faster the visual motion, the longer the perceived duration. In contrast, the actual execution of the arm movement does not contribute to this effect, but impairs discrimination performance by dual-task interference. We also show that additional training of the motor task attenuates the interference, but does not affect the distortion of subjective duration. The study demonstrates direct influence of visual motion on auditory temporal representations, which is independent of attentional modulation. At the same time, it provides causal support for the notion that time perception and continuous motor timing rely on separate mechanisms, a proposal that was formerly supported by correlational evidence only. The results constitute a counterexample to the modality appropriateness hypothesis and are best explained by Bayesian integration of modality-specific temporal information into a centralized "temporal hub".  相似文献   

5.
Taylor AM  Reby D  McComb K 《PloS one》2011,6(2):e17069
While the perception of size-related acoustic variation in animal vocalisations is well documented, little attention has been given to how this information might be integrated with corresponding visual information. Using a cross-modal design, we tested the ability of domestic dogs to match growls resynthesized to be typical of either a large or a small dog to size-matched models. Subjects looked at the size-matched model significantly more often and for a significantly longer duration than at the incorrect model, showing that they have the ability to relate information about body size from the acoustic domain to the appropriate visual category. Our study suggests that the perceptual and cognitive mechanisms at the basis of size assessment in mammals have a multisensory nature, and calls for further investigations of the multimodal processing of size information across animal species.  相似文献   

6.
The aim of the study was to evaluate magnetic resonance imaging (MRI) findings in infants with periventricular leukomalacia (PVL) and West syndrome (WS) and determine the neurodevelopmental outcome in children with West syndrome and PVL. Ultrasound and brain MRI were performed in 37 infants with recognized PVL. PVL was categorized according to De Vries, whereas West syndrome was categorized according to International League Against Epilepsy 1989. West syndrome in our patients developed during the first 2 years of life. The most common interictal abnormality was hypsarrhythmia. All, except two patients had delayed development and various degrees of mental retardation. The most characteristic neuroimaging findings were major reduction in cerebral cortical gray matter volume, reduction in the volume of brain myelin, and delayed myelination. These findings may explain the anatomical association between the West syndrome onset and PVL and intellectual and cognitive deficit in premature infants with PVL.  相似文献   

7.

Background

Visual cross-modal re-organization is a neurophysiological process that occurs in deafness. The intact sensory modality of vision recruits cortical areas from the deprived sensory modality of audition. Such compensatory plasticity is documented in deaf adults and animals, and is related to deficits in speech perception performance in cochlear-implanted adults. However, it is unclear whether visual cross-modal re-organization takes place in cochlear-implanted children and whether it may be a source of variability contributing to speech and language outcomes. Thus, the aim of this study was to determine if visual cross-modal re-organization occurs in cochlear-implanted children, and whether it is related to deficits in speech perception performance.

Methods

Visual evoked potentials (VEPs) were recorded via high-density EEG in 41 normal hearing children and 14 cochlear-implanted children, aged 5–15 years, in response to apparent motion and form change. Comparisons of VEP amplitude and latency, as well as source localization results, were conducted between the groups in order to view evidence of visual cross-modal re-organization. Finally, speech perception in background noise performance was correlated to the visual response in the implanted children.

Results

Distinct VEP morphological patterns were observed in both the normal hearing and cochlear-implanted children. However, the cochlear-implanted children demonstrated larger VEP amplitudes and earlier latency, concurrent with activation of right temporal cortex including auditory regions, suggestive of visual cross-modal re-organization. The VEP N1 latency was negatively related to speech perception in background noise for children with cochlear implants.

Conclusion

Our results are among the first to describe cross modal re-organization of auditory cortex by the visual modality in deaf children fitted with cochlear implants. Our findings suggest that, as a group, children with cochlear implants show evidence of visual cross-modal recruitment, which may be a contributing source of variability in speech perception outcomes with their implant.  相似文献   

8.
The purpose of this study was to question the correlation of different grades of periventricular leukomalacia (PVL) and subsequent neurodevelopmental outcome. In a prospective study we followed 52 preterm infants. Infants were divided into three groups according to their cranial ultrasound findings of PVL (De Vries classification). Seventeen children had PVL 1, 20 children had PVL 2, and 15 children had PVL 3. All 15 (100%) children with PVL 3 developed cerebral palsy with additional visual perceptual dysfunctions and epilepsy. Children with PVL 1 had high frequency of mild neuromotoric delay and visual impairment. PVL 2 and 3 have great predictive value for subsequent severe neurodevelopmental disorder which refers to cerebral palsy, different cognitive deficits, vision impairment and epilepsy. We have determined that due to high frequency of visual impairment and epilepsy we need to include neurophysiologic examinations very early in children with PVL lesions.  相似文献   

9.

Background

The duration of sounds can affect the perceived duration of co-occurring visual stimuli. However, it is unclear whether this is limited to amodal processes of duration perception or affects other non-temporal qualities of visual perception.

Methodology/Principal Findings

Here, we tested the hypothesis that visual sensitivity - rather than only the perceived duration of visual stimuli - can be affected by the duration of co-occurring sounds. We found that visual detection sensitivity (d’) for unimodal stimuli was higher for stimuli of longer duration. Crucially, in a cross-modal condition, we replicated previous unimodal findings, observing that visual sensitivity was shaped by the duration of co-occurring sounds. When short visual stimuli (∼24 ms) were accompanied by sounds of matching duration, visual sensitivity was decreased relative to the unimodal visual condition. However, when the same visual stimuli were accompanied by longer auditory stimuli (∼60–96 ms), visual sensitivity was increased relative to the performance for ∼24 ms auditory stimuli. Across participants, this sensitivity enhancement was observed within a critical time window of ∼60–96 ms. Moreover, the amplitude of this effect correlated with visual sensitivity enhancement found for longer lasting visual stimuli across participants.

Conclusions/Significance

Our findings show that the duration of co-occurring sounds affects visual perception; it changes visual sensitivity in a similar way as altering the (actual) duration of the visual stimuli does.  相似文献   

10.
An event in one sensory modality can phase reset brain oscillations concerning another modality. In principle, this may result in stimulus-locked periodicity in behavioral performance. Here we considered this possible cross-modal impact of a sound for one of the best-characterized rhythms arising from the visual system, namely occipital alpha-oscillations (8-14 Hz). We presented brief sounds and concurrently recorded electroencephalography (EEG) and/or probed visual cortex excitability (phosphene perception) through occipital transcranial magnetic stimulation (TMS). In a first, TMS-only experiment, phosphene perception rate against time postsound showed a periodic pattern cycling at ~10 Hz phase-aligned to the sound. In a second, combined TMS-EEG experiment, TMS-trials reproduced the cyclical phosphene pattern and revealed a ~10 Hz pattern also for EEG-derived measures of occipital cortex reactivity to the TMS pulses. Crucially, EEG-data from intermingled trials without TMS established cross-modal phase-locking of occipitoparietal alpha oscillations. These independently recorded variables, i.e., occipital cortex excitability and reactivity and EEG phase dynamics, were significantly correlated. This shows that cross-modal phase locking of oscillatory visual cortex activity can arise in the human brain to affect perceptual and EEG measures of visual processing in a cyclical manner, consistent with occipital alpha oscillations underlying a rapid cycling of neural excitability in visual areas.  相似文献   

11.
Infants and adults frequently observe actions performed jointly by more than one person. Research in action perception, however, has focused largely on actions performed by an individual person. Here, we explore how 9- and 12-month-old infants and adults perceive a block-stacking action performed by either one agent (individual condition) or two agents (joint condition). We used eye tracking to measure the latency of participants’ gaze shifts towards action goals. Adults anticipated goals in both conditions significantly faster than infants, and their gaze latencies did not differ between conditions. By contrast, infants showed faster anticipation of goals in the individual condition than in the joint condition. This difference was more pronounced in 9-month-olds. Further analyses of fixations examined the role of visual attention in action perception. These findings are cautiously interpreted in terms of low-level processing in infants and higher-level processing in adults. More precisely, our results suggest that adults are able to infer the overarching joint goal of two agents, whereas infants are not yet able to do so and might rely primarily on visual cues to infer the respective sub-goals. In conclusion, our findings indicate that the perception of joint action in infants develops differentially from that of individual action.  相似文献   

12.
In the past decades, multiple studies have been interested in developmental patterns of the visual system in healthy infants. During the first year of life, differential maturational changes have been observed between the Magnocellular (P) and the Parvocellular (P) visual pathways. However, few studies investigated P and M system development in infants born prematurely. The aim of the present study was to characterize P and M system maturational differences between healthy preterm and fullterm infants through a critical period of visual maturation: the first year of life. Using a cross-sectional design, high-density electroencephalogram (EEG) was recorded in 31 healthy preterms and 41 fullterm infants of 3, 6, or 12 months (corrected age for premature babies). Three visual stimulations varying in contrast and spatial frequency were presented to stimulate preferentially the M pathway, the P pathway, or both systems simultaneously during EEG recordings. Results from early visual evoked potentials in response to the stimulation that activates simultaneously both systems revealed longer N1 latencies and smaller P1 amplitudes in preterm infants compared to fullterms. Moreover, preterms showed longer N1 and P1 latencies in response to stimuli assessing the M pathway at 3 months. No differences between preterms and fullterms were found when using the preferential P system stimulation. In order to identify the cerebral generator of each visual response, distributed source analyses were computed in 12-month-old infants using LORETA. Source analysis demonstrated an activation of the parietal dorsal region in fullterm infants, in response to the preferential M pathway, which was not seen in the preterms. Overall, these findings suggest that the Magnocellular pathway development is affected in premature infants. Although our VEP results suggest that premature children overcome, at least partially, the visual developmental delay with time, source analyses reveal abnormal brain activation of the Magnocellular pathway at 12 months of age.  相似文献   

13.
Recent research has demonstrated that a deficit of endogenous attention (EA) is a main and stable characteristic of the mental development in healthy extremely premature (HEP) infants from the age of 2 years. A study was made of the differences in EA (anticipatory attention) between full-term (FT) and HEP infants, both aged 5 months (the HEP infants’ ages were corrected for prematurity). The general psychomotor development of the HEP infants was comparable to that of the age-matched FT infants. However, the HEP infants significantly differed from the FT infants in the ability to keep the attention on an object absent in the visual field. Unlike the HEP infants, the FT infants demonstrated a predominance of EA over all other types of attention in the visual expectation paradigm, as confirmed by ANOVA with the factors Maturity and Attention Type. Comparison of the frequency of different types of attention between the two groups showed that the EA frequency in the HEP infants was significantly lower than that in the FT infants. The findings showed that HEP infants, even those with a low risk for abnormal psychomotor development, demonstrate the impairment of EA control as early as at the age of 5 months.__________Translated from Fiziologiya Cheloveka, Vol. 31, No. 3, 2005, pp. 24–31.Original Russian Text Copyright © 2005 by Stroganova, Posikera, Pisarevskii.  相似文献   

14.
EEG indicators of endogenous attention (EnA) were studied in healthy infants carried to term and extremely preterm infants at a corrected age of five months. The cortical topography of the spectral amplitudes of the EEG θ rhythm was studied during long-term attention of the children to a new visual stimulus (exogenous attention, ExA) and during the retention of anticipatory attention under the conditions of constant appearance and disappearance of a stimulus in the paradigm of visual expectation (EnA). The relationship between reactive changes in the EEG θ rhythm during the retention of EnA and the behavioral parameters of the infant’s ability to retain this type of attention was also assessed. In five-month-old infants, the retention of EnA, in contrast to simpler types of attention to an exogenous stimulus, was accompanied by the appearance of a highly synchronized EEG θ rhythm (3.6–5.2 Hz) with a topical amplitude maximum in the lower temporal associative areas of the cortex. The ability to maintain EnA in children of this age is directly related to the reactive increase in the θ rhythm in the lower temporal areas of the cortex during the retention of EnA as compared to ExA. The deficit of EnA control in healthy extremely preterm (HEP) infants was associated with a relative deficit of the functional synchronization of the θ rhythm in the lower temporal areas of the cortex during the retention of EnA compared to full-term infants. In HEP infants, a decreased synchronization of the θ rhythm was equally typical of EnA and ExA. However, its cortical location depended on the type of attention. The functional nature of the θ rhythm inhibition in HEP infants suggests that this abnormality was related to alterations in the neurotransmitter interactions between the limbic and cortical structures, rather than to structural defects. These alterations could be one of the causes of the partial deficit of EnA in HEP infants.  相似文献   

15.
Sensory impairment is defined as the inability to interpret outside stimuli such as visual, auditory, verbal, sense of touch, taste or smell or feelings of pain. This leads to absence of sensation and neuronal coordination. The impairment may be caused by ageing and other physiological changes, accident or injuries or can be found in some cases of mental retardation (MR) also referred to as intellectual disability. Known cases of MR involving inability to accurately interpret an outside source or stimuli are: Fragile-X syndrome; Tuberous sclerosis complex (TSC) with associated autism spectrum disorder (ASD); Rett syndrome; Autism and ASD with or without MR; Chromosome 22q13.3 deletion syndrome; familial dysautonomia, Prader-Willi's syndrome, Williams syndrome. In this review we will discuss in particular form of ASD and altered sensory sensitivity. The role of NGF in causing pronociceptive activity and its role in peripheral sensitisation is discussed under the light of its involvement in forms of MR where loss of pain perception is a main feature due to mutations to NGF receptors or NGF genes during development. Other forms of MR with altered sensory impairment will be considered as well as additional potential mechanisms involved.  相似文献   

16.
The visual evoked potentials (EPs) in response to lateralized and central visual symbols under the conditions of involuntary (passive viewing) and selective attention (when one of the symbols was a target and required a rapid and precise motor reaction) are considered. The evoked potentials in the occipital, parietal, and frontal derivations were recorded in 20 healthy subjects. It was shown that the EP during selective attention are most pronounced and more alike in the parietal derivations. A strong positive correlation was revealed between the EP amplitude ([N1–P3] component) and the EP stability (correlation between the repeated EP). The involuntary and voluntary forms of attention supplement each other: the more expressed the involuntary attention (assessed by the [N1–P3] component) the higher the EP to target stimuli during voluntary attention and the shorter the reaction time. It is suggested that the role of visual attention consists in the increase and stabilization of cortical activity (primarily, the parietal regions) engaged in solving a visual task.  相似文献   

17.
Visual perception can be modulated by sounds. A drastic example of this is the sound-induced flash illusion: when a single flash is accompanied by two bleeps, it is sometimes perceived in an illusory fashion as two consecutive flashes. However, there are strong individual differences in proneness to this illusion. Some participants experience the illusion on almost every trial, whereas others almost never do. We investigated whether such individual differences in proneness to the sound-induced flash illusion were reflected in structural differences in brain regions whose activity is modulated by the illusion. We found that individual differences in proneness to the illusion were strongly and significantly correlated with local grey matter volume in early retinotopic visual cortex. Participants with smaller early visual cortices were more prone to the illusion. We propose that strength of auditory influences on visual perception is determined by individual differences in recurrent connections, cross-modal attention and/or optimal weighting of sensory channels.  相似文献   

18.
Mismatch negativity of ERP in cross-modal attention   总被引:1,自引:0,他引:1  
Event-related potentials were measured in 12 healthy youth subjects aged 19-22 using the paradigm "cross-modal and delayed response" which is able to improve unattended purity and to avoid the effect of task target on the deviant components of ERP. The experiment included two conditions: (i) Attend visual modality, ignore auditory modality; (ii) attend auditory modality, ignore visual modality. The stimuli under the two conditions were the same. The difference wave was obtained by subtracting ERPs of the standard stimuli from that of the deviant stim-uli. The present results showed that mismatch negativity (MMN), N2b and P3 components can be produced in the auditory and visual modalities under attention condition. However, only MMN was observed in the two modalities un-der inattention condition. Auditory and visual MMN have some features in common: their largest MMN wave peaks were distributed respectively over their primary sensory projection areas of the scalp under attention condition, but over front  相似文献   

19.
Periventricular leukomalacia (PVL) is a neonatal white matter damage of the brain of pre-term infants that often leads to cerebral palsy (CP). At present, diagnosis of PVL can be done by magnetic resonance imaging (MRI) and ultrasonography only when the infant is at least one week of age. No biochemical methods are available to identify high-risk infants at birth. Cytokines are usually not present in the cord blood but recently an elevation of IL-6 and TNF-alpha levels has been reported in amniotic fluid, cord blood and brain sections of infants with white matter damages. Levels of interleukin-18 (IL-18), a pleiotropic cytokines expressed in the brain and many other tissues, are highly sensitive to pathophysiological changes to raise the possibility that IL-18 may provide a useful indicator of PVL. The cord blood from 17 pre-term infants with PVL, 38 pre-term infants without PVL, and 30 normal full-term infants were retrospectively analysed for IL-18, IL-6, IL-1beta, and TNF-alpha. The possible factors involved in alteration of IL-18 concentration in relation to PVL and CP were examined. IL-18 is undetectable in the cord blood of normal full-term infants. However, high levels of IL-18 exist in the cord blood samples obtained from pre-term infants who neonatally developed PVL followed by CP. For pre-term infants under 35 weeks of gestation, seven out of eight showing more than 200 pg/ml of IL-18 (87.5%) developed PVL neonatally, with five of them subsequently developing CP. In contrast, only five out of 38 pre-term infants with less than 100 pg/ml of IL-18 (13.2%) developed PVL. For pre-term infants with less than 30 weeks of gestation, eight out of nine showing more than 100 pg/ml of IL-18 (88.9%) developed PVL, with six of these eight (75%) developing CP later. In conclusion, the presence of high levels of IL-18 in the cord blood of the pre-term infants is correlated with the incidence of PVL and CP and may provide a prognostic marker applicable at birth.  相似文献   

20.
Evidence of visual-auditory cross-modal plasticity in deaf individuals has been widely reported. Superior visual abilities of deaf individuals have been shown to result in enhanced reactivity to visual events and/or enhanced peripheral spatial attention. The goal of this study was to investigate the association between visual-auditory cross-modal plasticity and speech perception in post-lingually deafened, adult cochlear implant (CI) users. Post-lingually deafened adults with CIs (N = 14) and a group of normal hearing, adult controls (N = 12) participated in this study. The CI participants were divided into a good performer group (good CI, N = 7) and a poor performer group (poor CI, N = 7) based on word recognition scores. Visual evoked potentials (VEP) were recorded from the temporal and occipital cortex to assess reactivity. Visual field (VF) testing was used to assess spatial attention and Goldmann perimetry measures were analyzed to identify differences across groups in the VF. The association of the amplitude of the P1 VEP response over the right temporal or occipital cortex among three groups (control, good CI, poor CI) was analyzed. In addition, the association between VF by different stimuli and word perception score was evaluated. The P1 VEP amplitude recorded from the right temporal cortex was larger in the group of poorly performing CI users than the group of good performers. The P1 amplitude recorded from electrodes near the occipital cortex was smaller for the poor performing group. P1 VEP amplitude in right temporal lobe was negatively correlated with speech perception outcomes for the CI participants (r = -0.736, P = 0.003). However, P1 VEP amplitude measures recorded from near the occipital cortex had a positive correlation with speech perception outcome in the CI participants (r = 0.775, P = 0.001). In VF analysis, CI users showed narrowed central VF (VF to low intensity stimuli). However, their far peripheral VF (VF to high intensity stimuli) was not different from the controls. In addition, the extent of their central VF was positively correlated with speech perception outcome (r = 0.669, P = 0.009). Persistent visual activation in right temporal cortex even after CI causes negative effect on outcome in post-lingual deaf adults. We interpret these results to suggest that insufficient intra-modal (visual) compensation by the occipital cortex may cause negative effects on outcome. Based on our results, it appears that a narrowed central VF could help identify CI users with poor outcomes with their device.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号