506 research outputs found
Multisensory Processes: A Balancing Act across the Lifespan.
Multisensory processes are fundamental in scaffolding perception, cognition, learning, and behavior. How and when stimuli from different sensory modalities are integrated rather than treated as separate entities is poorly understood. We review how the relative reliance on stimulus characteristics versus learned associations dynamically shapes multisensory processes. We illustrate the dynamism in multisensory function across two timescales: one long term that operates across the lifespan and one short term that operates during the learning of new multisensory relations. In addition, we highlight the importance of task contingencies. We conclude that these highly dynamic multisensory processes, based on the relative weighting of stimulus characteristics and learned associations, provide both stability and flexibility to brain functions over a wide range of temporal scales
A multisensory perspective on object memory.
Traditional studies of memory and object recognition involved objects presented within a single sensory modality (i.e., purely visual or purely auditory objects). However, in naturalistic settings, objects are often evaluated and processed in a multisensory manner. This begets the question of how object representations that combine information from the different senses are created and utilised by memory functions. Here we review research that has demonstrated that a single multisensory exposure can influence memory for both visual and auditory objects. In an old/new object discrimination task, objects that were presented initially with a task-irrelevant stimulus in another sense were better remembered compared to stimuli presented alone, most notably when the two stimuli were semantically congruent. The brain discriminates between these two types of object representations within the first 100ms post-stimulus onset, indicating early "tagging" of objects/events by the brain based on the nature of their initial presentation context. Interestingly, the specific brain networks supporting the improved object recognition vary based on a variety of factors, including the effectiveness of the initial multisensory presentation and the sense that is task-relevant. We specify the requisite conditions for multisensory contexts to improve object discrimination following single exposures, and the individual differences that exist with respect to these improvements. Our results shed light onto how memory operates on the multisensory nature of object representations as well as how the brain stores and retrieves memories of objects
Neonatal Multisensory Processing in Preterm and Term Infants Predicts Sensory Reactivity and Internalizing Tendencies in Early Childhood.
Multisensory processes include the capacity to combine information from the different senses, often improving stimulus representations and behavior. The extent to which multisensory processes are an innate capacity or instead require experience with environmental stimuli remains debated. We addressed this knowledge gap by studying multisensory processes in prematurely born and full-term infants. We recorded 128-channel event-related potentials (ERPs) from a cohort of 55 full-term and 61 preterm neonates (at an equivalent gestational age) in response to auditory, somatosensory, and combined auditory-somatosensory multisensory stimuli. Data were analyzed within an electrical neuroimaging framework, involving unsupervised topographic clustering of the ERP data. Multisensory processing in full-term infants was characterized by a simple linear summation of responses to auditory and somatosensory stimuli alone, which furthermore shared common ERP topographic features. We refer to the ERP topography observed in full-term infants as "typical infantile processing" (TIP). In stark contrast, preterm infants exhibited non-linear responses and topographies less-often characterized by TIP; there were distinct patterns of ERP topographies to multisensory and summed unisensory conditions. We further observed that the better TIP characterized an infant's ERPs, independently of prematurity, the more typical was the score on the Infant/Toddler Sensory Profile (ITSP) at 12 months of age and the less likely was the child to the show internalizing tendencies at 24 months of age. Collectively, these results highlight striking differences in the brain's responses to multisensory stimuli in children born prematurely; differences that relate to later sensory and internalizing functions
Contributions of Intraindividual and Interindividual Differences to Multisensory Processes.
Most evidence on the neural and perceptual correlates of sensory processing derives from studies that have focused on only a single sensory modality and averaged the data from groups of participants. Although valuable, such studies ignore the substantial interindividual and intraindividual differences that are undoubtedly at play. Such variability plays an integral role in both the behavioral/perceptual realms and in the neural correlates of these processes, but substantially less is known when compared with group-averaged data. Recently, it has been shown that the presentation of stimuli from two or more sensory modalities (i.e., multisensory stimulation) not only results in the well-established performance gains but also gives rise to reductions in behavioral and neural response variability. To better understand the relationship between neural and behavioral response variability under multisensory conditions, this study investigated both behavior and brain activity in a task requiring participants to discriminate moving versus static stimuli presented in either a unisensory or multisensory context. EEG data were analyzed with respect to intraindividual and interindividual differences in RTs. The results showed that trial-by-trial variability of RTs was significantly reduced under audiovisual presentation conditions as compared with visual-only presentations across all participants. Intraindividual variability of RTs was linked to changes in correlated activity between clusters within an occipital to frontal network. In addition, interindividual variability of RTs was linked to differential recruitment of medial frontal cortices. The present findings highlight differences in the brain networks that support behavioral benefits during unisensory versus multisensory motion detection and provide an important view into the functional dynamics within neuronal networks underpinning intraindividual performance differences
Stem cell factor (SCF) and c-kit in the ovine fetal testis in normal and nutrition perturbed pregnancies
Stem cell factor (SCF) and c-kit in the ovine fetal testis in normal and nutrition perturbed pregnancie
The Dual Nature of Early-Life Experience on Somatosensory Processing in the Human Infant Brain.
Every year, 15 million preterm infants are born, and most spend their first weeks in neonatal intensive care units (NICUs) [1]. Although essential for the support and survival of these infants, NICU sensory environments are dramatically different from those in which full-term infants mature and thus likely impact the development of functional brain organization [2]. Yet the integrity of sensory systems determines effective perception and behavior [3, 4]. In neonates, touch is a cornerstone of interpersonal interactions and sensory-cognitive development [5-7]. NICU treatments used to improve neurodevelopmental outcomes rely heavily on touch [8]. However, we understand little of how brain maturation at birth (i.e., prematurity) and quality of early-life experiences (e.g., supportive versus painful touch) interact to shape the development of the somatosensory system [9]. Here, we identified the spatial, temporal, and amplitude characteristics of cortical responses to light touch that differentiate them from sham stimuli in full-term infants. We then utilized this data-driven analytical framework to show that the degree of prematurity at birth determines the extent to which brain responses to light touch (but not sham) are attenuated at the time of discharge from the hospital. Building on these results, we showed that, when controlling for prematurity and analgesics, supportive experiences (e.g., breastfeeding, skin-to-skin care) are associated with stronger brain responses, whereas painful experiences (e.g., skin punctures, tube insertions) are associated with reduced brain responses to the same touch stimuli. Our results shed crucial insights into the mechanisms through which common early perinatal experiences may shape the somatosensory scaffolding of later perceptual, cognitive, and social development
Quantized spin waves in the metallic state of magnetoresistive manganites
High resolution spin waves measurements have been carried out in
ferromagnetic (F) La(1-x)(Sr,Ca)xMnO3 with x(Sr)=0.15, 0.175, 0.2, 0.3 and
x(Ca)=0.3. In all q-directions, close to the zone boundary, the spin wave
spectra consist of several energy levels, with the same values in the metallic
and the x\approx 1/8 ranges. Mainly the intensity varies, jumping from the
lower energy levels determined in the x\approx 1/8 range to the higher energy
ones observed in the metallic state. On the basis of a quantitative agreement
found for x(Sr)=0.15 in a model of ordered 2D clusters, the spin wave anomalies
of the metallic state can be interpreted in terms of quantized spin waves
within the same 2D clusters, embedded in a 3D matrix.Comment: 4 pages, 5 figure
Professionalism, Golf Coaching and a Master of Science Degree: A commentary
As a point of reference I congratulate Simon Jenkins on tackling the issue of professionalism in coaching. As he points out coaching is not a profession, but this does not mean that coaching would not benefit from going through a professionalization process. As things stand I find that the stimulus article unpacks some critically important issues of professionalism, broadly within the context of golf coaching. However, I am not sure enough is made of understanding what professional (golf) coaching actually is nor how the development of a professional golf coach can be facilitated by a Master of Science Degree (M.Sc.). I will focus my commentary on these two issues
Molecular and Historical Aspects of Corn Belt Dent Diversity
Tens-of-thousands of open-pollinated cultivars of corn (Zea mays L.) are being maintained in germplasm banks. Knowledge of the amount and distribution of genetic variation within and among accessions can aid end users in choosing among them. We estimated molecular genetic variation and looked for influences of pedigree, adaptation, and migration in the genetic makeup of conserved Corn-Belt Dent-related germplasm. Plants sampled from 57 accessions representing Corn-Belt Dents, Northern Flints, Southern Dents, plus 12 public inbreds, were genotyped at 20 simple sequence repeat (SSR) loci. For 47 of the accessions, between 5 and 23 plants per accession were genotyped (mean = 9.3). Mean number of alleles per locus was 6.5 overall, 3.17 within accessions, and 3.20 within pooled inbreds. Mean gene diversity was 0.53 within accessions and 0.61 within pooled inbreds. Open-pollinated accessions showed a tendency toward inbreeding (FIS = 0.09), and 85% of genetic variation was shared among them. A Fitch-Margoliash tree strongly supported the distinctiveness of flint from dent germplasm but did not otherwise reveal evidence of genetic structure. Mantel tests revealed significant correlations between genetic distance and geographical (r = 0.54, P= 0.04) or maturity zone (r = 0.33, P = 0.03) distance only if flint germplasm was included in the analyses. A significant correlation (r = 0.76, P \u3c 0.01) was found between days to pollen shed and maturity zone of accession origin. Pedigree, rather than migration or selection, has most influenced the genetic structure of the extant representatives of the open-pollinated cultivars at these SSR loci
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An aphasia research agenda - a consensus statement from the collaboration of aphasia trialists.
Coordination of international aphasia research would minimise duplication of effort, support synergistic international activities across languages and multidisciplinary perspectives, and promote high-quality conduct and reporting of aphasia research, thereby increasing the relevance, transparency, and implementation of findings. The Collaboration of Aphasia Trialists (CATs) sought to develop an aphasia research agenda to direct future research activities, based on priorities shared by people with aphasia, family members, and healthcare professionals. Our established international research network spanning 33 countries contributed to this activity. Research literature reporting the priorities of stakeholders was reviewed and synthesised (phase 1). Representatives from Working Groups on Aphasia Assessment & Outcomes, Prognosis & Predictors of Recovery, Effectiveness of Interventions, and Societal Impact & Reintegration participated in a two-day research agenda setting meeting. The CATs expert panel refined research objectives and identified constituent components of research and methodological developments required to address these research components. The objectives and research components were grouped into overarching themes (phase 2). The resultant list was then circulated to more than 180 CATs members for review, revision, and approval. Consensus on the final aphasia research agenda and road-map was reached by CATs executive committee (phase 3). The expert panel identified five overarching research themes: (i) evidence-based interventions for people with aphasia, (ii) effective interventions to support those communicating with people with aphasia, (iii) cross-linguistic assessment and core outcomes for aphasia research, (iv) predictors of language recovery, and (v) clinical implementation of research findings. Within these broad themes, 30 research objectives and 91 individual aphasia research components were identified and sequentially ordered. This agenda builds on research priorities identified by people with aphasia and their families, and includes priorities of healthcare professionals and researchers, and will support the rehabilitation and recovery of people with aphasia. Our internationally relevant research agenda promotes rigour in methodology, considers international applicability, synergistic activities, and sharing of resources and expertise
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