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Using a combined sample of adolescent twins, biological siblings, and adoptive siblings, we estimated and compared the differential
shared-environmentality for high cognitive ability and the shared-environmental variance for the full range of ability during
adolescence. Estimates obtained via multiple methods were in the neighborhood of 0.20, and suggest a modest effect of the
shared environment on both high and full-range ability. We then examined the association of ability with three measures of
the family environment in a subsample of adoptive siblings: parental occupational status, parental education, and disruptive
life events. Only parental education showed significant (albeit modest) association with ability in both the biological and
adoptive samples. We discuss these results in terms of the need for cognitive-development research to combine genetically
sensitive designs and modern statistical methods with broad, thorough environmental measurement.
相似文献
Robert M. KirkpatrickEmail: |
3.
Lorenza Serena Colzato Wery P. M. van den Wildenberg Nelleke C. van Wouwe Merel M. Pannebakker Bernhard Hommel 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,196(3):467-474
The inhibitory control of actions has been claimed to rely on dopaminergic pathways. Given that this hypothesis is mainly
based on patient and drug studies, some authors have questioned its validity and suggested that beneficial effects of dopaminergic
stimulants on response inhibition may be limited to cases of suboptimal inhibitory functioning. We present evidence that,
in carefully selected healthy adults, spontaneous eyeblink rate, a marker of central dopaminergic functioning, reliably predicts
the efficiency in inhibiting unwanted action tendencies in a stop-signal task. These findings support the assumption of a
modulatory role for dopamine in inhibitory action control.
相似文献
Lorenza Serena ColzatoEmail: |
4.
Randomizing visual feedback in manual aiming: reminiscence of the previous trial condition and prior knowledge of feedback availability 总被引:1,自引:1,他引:0
Cheng DT Luis M Tremblay L 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,189(4):403-410
A trial-by-trial analysis was used to systematically examine the influence of switching visual conditions on visual feedback
utilization for a manual aiming movement. In experiment one, vision was randomly manipulated from trial to trial with no more
than four consecutive trials in the same visual condition. In experiment two, participants were provided with certainty of
visual feedback availability prior to every trial. Results of both studies revealed that movement endpoint variability was
most associated with visual feedback availability on the previous trial. Furthermore, correlation analyses comparing movement
trajectory at 25, 50 and 75% with movement end (i.e. 100%) revealed that the efficiency of online corrections also depends
on the availability of visual feedback on the previous trial. These results suggest that the accuracy of an aiming movement
is highly dependent on processing of offline visual information from the preceding trial.
This study was supported by a grant from the Natural Sciences and Engineering Research Council of Canada (NSERC) awarded to
Luc Tremblay.
相似文献
Darian T. ChengEmail: |
Luc Tremblay (Corresponding author)Email: |
5.
It is well-established that genetic factors account for large proportions of individual differences in multiple cognitive
abilities. It is also well-established that individual differences in performance on many different cognitive ability measures
are strongly correlated. Recent empirical investigations, however, have suggested two interesting qualifications to these
well-established findings: Genetic variance in cognitive abilities is higher in richer home environments (gene-by-environment
interaction), and common variance in different cognitive abilities is lower at higher levels of overall ability (nonlinear
factor structure). Although they have been investigated independently, these two phenomena may interact, because richer environments
are routinely associated with higher ability levels. Using simulation we demonstrate how un-modeled nonlinear factor structure
can obscure interpretation of gene-by-environment interaction. We then reanalyze data from the National Collaborative Perinatal
Project, previously used by Turkheimer et al. (2003; Psychol Science), with a two-step method to model both phenomena.
相似文献
Elliot M. Tucker-DrobEmail: |
6.
Jansson E Wilson AD Williams JH Mon-Williams M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2007,182(4):549-558
Recent behavioural research has investigated whether viewing someone perform an action results in activation of that action
by the observer. Postulated empirical support for this ‘ideo-motor (IM) conjecture’ typically rests upon two types of experimental
paradigm (reaction time and movement tracking tasks). These paradigms purport to show movement facilitation when compatible
movements are observed and vice versa, but only for biological stimuli. Unfortunately, these paradigms often contain confounding
(and unavoidable) generic stimulus–response compatibility effects that are not restricted to observed human movement. The
current study demonstrates in three experiments that equivalent compatibility effects can be produced by non-biological stimuli.
These results suggest that existing empirical paradigms may not, and perhaps cannot, support the IM-conjecture.
相似文献
Andrew D. WilsonEmail: |
7.
Coping with racism: a selective review of the literature and a theoretical and methodological critique 总被引:2,自引:1,他引:1
Elizabeth Brondolo Nisha Brady ver Halen Melissa Pencille Danielle Beatty Richard J. Contrada 《Journal of behavioral medicine》2009,32(1):64-88
Racism is a stressor that contributes to racial/ethnic disparities in mental and physical health and to variations in these
outcomes within racial and ethnic minority groups. The aim of this paper is to identify and discuss key issues in the study
of individual-level strategies for coping with interpersonal racism. We begin with a discussion of the ways in which racism
acts as a stressor and requires the mobilization of coping resources. Next, we examine available models for describing and
conceptualizing strategies for coping with racism. Third, we discuss three major forms of coping: racial identity development,
social support seeking and anger suppression and expression. We examine empirical support for the role of these coping strategies
in buffering the impact of racism on specific health-related outcomes, including mental health (i.e., specifically, self-reported
psychological distress and depressive symptoms), self-reported physical health, resting blood pressure levels, and cardiovascular
reactivity to stressors. Careful examination of the effectiveness of individual-level coping strategies can guide future interventions
on both the individual and community levels.
相似文献
Elizabeth BrondoloEmail: |
8.
William S. Kremen Kristen C. Jacobson Matthew S. Panizzon Hong Xian Lindon J. Eaves Seth A. Eisen Ming T. Tsuang Michael J. Lyons 《Behavior genetics》2009,39(2):133-144
We examined the genetic architecture of a Tower of London test of planning and problem-solving in 690 middle-aged male twins.
Phenotypic analyses revealed only one general factor, but the best-fitting genetic model indicated two correlated genetic
factors: speed and efficiency. One variable—number of attempts required to mentally figure the puzzles—loaded on both factors.
Shared environmental effects could be dropped with virtually no reduction in model fit. Despite significant nonshared environmental
correlations across measures, there was no discernable nonshared environmental factor structure. The correlation between genetic
factors (r = 0.46) and the variable loading on both factors could reflect modulation of planning, testing alternatives, and working
memory that are required to perform the test. Such coordinated activity is consistent with the notion of a supervisory attentional
system, a central executive, or metacognitive ability. The different phenotypic and genetic factor results suggest that relying
solely on the former could obscure genetic associations.
相似文献
William S. KremenEmail: |
9.
Michelle Jarick Jeffery A. Jones 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,195(2):175-182
Research demonstrates that listening to and viewing speech excites tongue and lip motor areas involved in speech production.
This perceptual-motor relationship was investigated behaviourally by presenting video clips of a speaker producing vowel-consonant-vowel
syllables in three conditions: visual-only, audio-only, and audiovisual. Participants identified target letters that were
flashed over the mouth during the video, either manually or verbally as quickly as possible. Verbal responses were fastest
when the target matched the speech stimuli in all modality conditions, yet optimal facilitation was observed when participants
were presented with visual-only stimuli. Critically, no such facilitation occurred when participants were asked to identify
the target manually. Our findings support previous research suggesting a close relationship between speech perception and
production by demonstrating that viewing speech can ‘prime’ our motor system for subsequent speech production.
相似文献
Jeffery A. JonesEmail: |
10.
Di Luca S Pesenti M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,185(1):27-39
Discrete numerosities can be represented by various finger configurations. The impact of counting strategies on these configurations
and their possible semantic status were investigated in young adults. Experiment 1 showed that young adults named numerical
finger configurations faster when they conformed to their own canonical finger-counting habits than when they did not. Experiment
2 showed that numeral finger configurations used as unconsciously presented primes speeded up numerical comparative judgements
of Arabic numeral targets. Participants responded faster and made fewer errors with numerical than with non-numerical primes,
and when primes and targets were congruent (i.e., leading to the same response). Moreover, this priming effect generalised
to novel never consciously seen numerosities for canonical configurations but not for non-canonical ones. These results support
the idea that canonical finger configurations automatically activate number semantics whereas non-canonical ones do not.
相似文献
Mauro PesentiEmail: |
11.
Stable RNA interference (RNAi) is commonly achieved by recombinant expression of short hairpin RNA (shRNA). To generate virus-resistant
cell lines, we cloned a shRNA cassette against the phosphoprotein gene of respiratory syncytial virus (RSV) into a polIII-driven
plasmid vector. Analysis of individual stable transfectants showed a spectrum of RSV resistance correlating with the levels
of shRNA expressed from different chromosomal locations. Interestingly, resistance in a minority of clones was due to mono-allelic
disruption of the cellular gene for vasodilator-stimulated phosphoprotein (VASP). Thus, pure clones of chromosomally integrated
DNA-directed RNAi can exhibit gene disruption phenotypes resembling but unrelated to RNAi.
相似文献
Sailen BarikEmail: |
12.
Location memory biases reveal the challenges of coordinating visual and kinesthetic reference frames
Simmering VR Peterson C Darling W Spencer JP 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,184(2):165-178
Five experiments explored the influence of visual and kinesthetic/proprioceptive reference frames on location memory. Experiments
1 and 2 compared visual and kinesthetic reference frames in a memory task using visually-specified locations and a visually-guided
response. When the environment was visible, results replicated previous findings of biases away from the midline symmetry
axis of the task space, with stability for targets aligned with this axis. When the environment was not visible, results showed
some evidence of bias away from a kinesthetically-specified midline (trunk anterior–posterior [a–p] axis), but there was little
evidence of stability when targets were aligned with body midline. This lack of stability may reflect the challenges of coordinating
visual and kinesthetic information in the absence of an environmental reference frame. Thus, Experiments 3–5 examined kinesthetic
guidance of hand movement to kinesthetically-defined targets. Performance in these experiments was generally accurate with
no evidence of consistent biases away from the trunk a–p axis. We discuss these results in the context of the challenges of
coordinating reference frames within versus between multiple sensori-motor systems.
相似文献
Vanessa R. SimmeringEmail: |
13.
Sappinia diploidea is known as a free-living amoeba of worldwide distribution and has also been reported as causative agent of a brain infection
in an immunocompetent young man. In the current study, we were able to isolate eight strains of S. diploidea-like amoebae identified by light microscopy from different habitats. Cultures of all strains were established successfully
for molecular characterization. The small subunit ribosomal RNA genes of all strains were sequenced and compared to one another,
to the neotype of S. diploidea, and to strains of Sappinia pedata, the only other Sappinia species known to date, from GenBank by multiple sequence alignment and cluster analysis. Altogether, the phylogenetic position
of the genus Sappinia within the Thecamoebidae was corroborated; however, it was shown that the genus splits into several well-separated clusters
making the establishment of new species within this genus inevitable. Furthermore, two of the S. diploidea-like strains were actually more closely related to S. pedata than to S. diploidea, although the diagnostically relevant standing form which seems to be characteristic for S. pedata was not observed in either of the two strains.
Claudia Wylezich and Julia Walochnik have contributed equally to this work.
相似文献
Claudia Wylezich (Corresponding author)Email: |
Rolf MichelEmail: |
14.
Chun Sing Louis Tsui John Q. Gan Stephen J. Roberts 《Medical & biological engineering & computing》2009,47(3):257-265
Due to the non-stationarity of EEG signals, online training and adaptation are essential to EEG based brain–computer interface
(BCI) systems. Self-paced BCIs offer more natural human–machine interaction than synchronous BCIs, but it is a great challenge
to train and adapt a self-paced BCI online because the user’s control intention and timing are usually unknown. This paper
proposes a novel motor imagery based self-paced BCI paradigm for controlling a simulated robot in a specifically designed
environment which is able to provide user’s control intention and timing during online experiments, so that online training
and adaptation of the motor imagery based self-paced BCI can be effectively investigated. We demonstrate the usefulness of
the proposed paradigm with an extended Kalman filter based method to adapt the BCI classifier parameters, with experimental
results of online self-paced BCI training with four subjects.
相似文献
Chun Sing Louis TsuiEmail: |
15.
Coats R Bingham GP Mon-Williams M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,189(2):211-220
Feedback is a central feature of neural systems and of crucial importance to human behaviour as shown in goal directed actions
such as reaching-to-grasp. One important source of feedback in reach-to-grasp behaviour arises from the haptic information
obtained after grasping an object. We manipulated the felt distance and/or size of a visually constant object to explore the
role of haptic information in the calibration of reaching and grasping. Crucially, our design explored post-adaptation effects
rather than the previously documented role of haptic information in movement organisation. A post-adaptation reach-to-grasp
task showed: (1) distorted haptic feedback caused recalibration; (2) reach distance and grasp size could be calibrated separately
but, if calibrated simultaneously, then (3) recalibration was greater when distance and size changed in a consistent (e.g.
reaching for a larger object at a greater distance) rather than an inconsistent (e.g. a smaller object at a greater distance)
fashion. These interactions reveal the integral nature of reach-to-grasp organization, that is, that reaching and grasping
are integrated components of a single action system.
相似文献
Geoffrey P. BinghamEmail: |
16.
Communicating bad news is never easy and for physicians these interactions may be a significant source of stress. To examine
the characteristics that make delivering of bad news stressful, two studies were conducted. In the first study, 37 physicians
generated 192 responses describing the characteristics that influence how difficult it is to break bad news. After sorting
the responses in terms of common themes, six categories were identified: Physician, Patient, Institutional, Illness, Relationship,
and Mishap. In Study 2, 115 physicians rated the degree of stress associated with each factor. Using principle component and
reliability analyses, empirical support was found for six categories. A higher-order factor analysis suggested the existence
of one over-arching factor. Items in the Mishap category were rated on average as the most stressful. Stress scores were largely
unrelated to years in practice, experience delivering bad news or training.
相似文献
J. T. PtacekEmail: |
17.
Modelling the human pharyngeal airway: validation of numerical simulations using in vitro experiments 总被引:1,自引:0,他引:1
Chouly F Van Hirtum A Lagrée PY Pelorson X Payan Y 《Medical & biological engineering & computing》2009,47(1):49-58
In the presented study, a numerical model which predicts the flow-induced collapse within the pharyngeal airway is validated
using in vitro measurements. Theoretical simplifications were considered to limit the computation time. Systematic comparisons
between simulations and measurements were performed on an in vitro replica, which reflects asymmetries of the geometry and
of the tissue properties at the base of the tongue and in pathological conditions (strong initial obstruction). First, partial
obstruction is observed and predicted. Moreover, the prediction accuracy of the numerical model is of 4.2% concerning the
deformation (mean quadratic error on the constriction area). It shows the ability of the assumptions and method to predict
accurately and quickly a fluid–structure interaction.
相似文献
Yohan PayanEmail: |
18.
Ashish Sharma Tony Pan B. Barla Cambazoglu Metin Gurcan Tahsin Kurc Joel Saltz 《Journal of digital imaging》2009,22(1):1-10
Collaborations in biomedical research and clinical studies require that data, software, and computational resources be shared
between geographically distant institutions. In radiology, there is a related issue of sharing remote DICOM data over the
Internet. This paper focuses on the problem of federating multiple image data resources such that clients can interact with
them as if they are stored in a centralized PACS. We present a toolkit, called VirtualPACS, to support this functionality.
Using the toolkit, users can perform standard DICOM operations (query, retrieve, and submit) across distributed image databases.
The key features of the toolkit are: (1) VirtualPACS makes it easy to use existing DICOM client applications for data access;
(2) it can easily be incorporated into an imaging workflow as a DICOM source; (3) using VirtualPACS, heterogeneous collections
of DICOM sources are exposed to clients through a uniform interface and common data model; and (4) DICOM image databases without
DICOM messaging can be accessed.
相似文献
Ashish SharmaEmail: |
19.
Skitzki JJ Chen Q Wang WC Evans SS 《Journal of molecular medicine (Berlin, Germany)》2007,85(12):1361-1367
The thermal element of fever has been found to be beneficial in models of infectious disease. The contributions of fever-range
temperatures to the efficacy of the adaptive immune response have only begun to be delineated. There is accumulating evidence
that fever-range thermal stress bolsters primary immune surveillance of lymph nodes and Peyer patches by augmenting lymphocyte
extravasation across specialized vessels termed high endothelial venules. Molecular mechanisms have recently come to light
by which the thermal component of fever alone may promote lymphocyte trafficking, and thereby the probability of mounting
a defense against microbial infection. Acquired knowledge of the molecular changes associated with thermal stress may allow
for the development of novel therapies for a variety of disease processes.
相似文献
Sharon S. EvansEmail: |
20.
James Danckert Lana Goldberg Carol Broderick 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,195(2):193-191
Neurophysiology and neuroimaging research implicates distinct regions of posterior parietal cortex for reaching versus grasping
and for completing these movements in central versus peripheral space. Typically, visuomotor tasks only examine movements
made in the frontoparallel plane. We examined a patient with a right superior parietal lesion encompassing the parietal-occipital
junction, the intraparietal sulcus and the putative human homologue of V6A on pointing tasks in the sagittal or frontoparallel
planes. The patient did not demonstrate a speed-accuracy trade-off, but did show larger times post-peak velocity for all movement
directions. Her movements in the sagittal axis were more disordered than movements in the frontoparallel plane. These data
indicate a role for superior parietal cortex in fine tuning of visually guided movements and more particularly for movements
made back towards the body.
相似文献
James DanckertEmail: Email: |