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1.
This study investigated cognitive representations and psychological effects of being ‘at-risk’ for cancer. Perceived personal
risk for cancer and causal attributions for cancer were measured in four groups: women identified as carriers of mutations
in breast/ovarian cancer genes BRCA1 BRCA2, habitual smokers, X-ray technicians, and an average-risk group. Despite differences
in awareness of their risk status and perceived risk for cancer, the groups did not differ in health anxiety, cancer worry
interference, and self-assessed health. Motivated reasoning processes were identified as potential strategies used by individuals
at-risk to regulate levels of psychological distress. Evidence for biased risk perceptions and unrealistic optimism were found
among smokers, and patterns indicative of self-enhancement through self-assessments and defensive discounting of cancer causal
attributions were found in the genetically susceptible group. These findings highlight the role of cognitive representations
in adjustment to being at-risk for cancer.
相似文献
Shoshana ShilohEmail: |
2.
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: |
3.
Nikolaev AR Gepshtein S Kubovy M van Leeuwen C 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,186(1):107-122
Perceptual grouping is a multi-stage process, irreducible to a single mechanism localized anatomically or chronometrically.
To understand how various grouping mechanisms interact, we combined a phenomenological report paradigm with high-density event-related
potential (ERP) measurements, using a 256-channel electrode array. We varied the relative salience of competing perceptual
organizations in multi-stable dot lattices and asked observers to report perceived groupings. The ability to discriminate
groupings (the grouping sensitivity) was positively correlated with the amplitude of the earliest ERP peak C1 (about 60 ms
after stimulus onset) over the middle occipital area. This early activity is believed to reflect spontaneous feed-forward
processes preceding perceptual awareness. Grouping sensitivity was negatively correlated with the amplitude of the next peak
P1 (about 110 ms), which is believed to reflect lateral and feedback interactions associated with perceptual awareness and
attention. This dissociation between C1 and P1 activity implies that the recruitment of fast, spontaneous mechanisms for grouping
leads to high grouping sensitivity. Observers who fail to recruit these mechanisms are trying to compensate by using later
mechanisms, which depend less on stimulus properties such as proximity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Andrey R. NikolaevEmail: URL: http://pdl.brain.riken.jp |
4.
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: |
5.
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: |
6.
D. Fuentes J. T. Oden K. R. Diller J. D. Hazle A. Elliott A. Shetty R. J. Stafford 《Annals of biomedical engineering》2009,37(4):763-782
An adaptive feedback control system is presented which employs a computational model of bioheat transfer in living tissue
to guide, in real-time, laser treatments of prostate cancer monitored by magnetic resonance thermal imaging. The system is
built on what can be referred to as cyberinfrastructure—a complex structure of high-speed network, large-scale parallel computing
devices, laser optics, imaging, visualizations, inverse-analysis algorithms, mesh generation, and control systems that guide
laser therapy to optimally control the ablation of cancerous tissue. The computational system has been successfully tested
on in vivo, canine prostate. Over the course of an 18 min laser-induced thermal therapy performed at M.D. Anderson Cancer Center (MDACC)
in Houston, Texas, the computational models were calibrated to intra-operative real-time thermal imaging treatment data and
the calibrated models controlled the bioheat transfer to within 5 °C of the predetermined treatment plan. The computational
arena is in Austin, Texas and managed at the Institute for Computational Engineering and Sciences (ICES). The system is designed
to control the bioheat transfer remotely while simultaneously providing real-time remote visualization of the on-going treatment.
Post-operative histology of the canine prostate reveal that the damage region was within the targeted 1.2 cm diameter treatment
objective.
相似文献
R. J. StaffordEmail: |
7.
In addition to multiple health benefits, participation in physical activity can enhance cognitive functioning. Less clear
is how reducing physical activity levels affects cognition, an issue potentially addressed by bed rest studies having included
cognitive tests. Detailed and reviewed here are 17 such studies, featuring 251 subjects, bed rest for 7–70 days, and tests
of cognition ranging from reaction time to executive functions. The reported effects of bed rest on cognitive performance
vary considerably, from a generally expected worsening to an improvement. Practice effects could be implicated in the performance
improvements, and reports of worsening are often of limited interpretability or the results were not replicated. Any cognitive
effects of bed rest thus remain to be established. Detrimental effects could influence the in-progress plans for human spaceflights
to Mars (simulated by bed rest), and have implications for medical conditions promoting inactivity and lifestyles that are
largely sedentary.
相似文献
Darren M. LipnickiEmail: |
8.
Daniel L. Rubin 《Journal of digital imaging》2008,21(4):355-362
The radiology community has recognized the need to create a standard terminology to improve the clarity of reports, to reduce
radiologist variation, to enable access to imaging information, and to improve the quality of practice. This need has recently
led to the development of RadLex, a controlled terminology for radiology. The creation of RadLex has proved challenging in
several respects: It has been difficult for users to peruse the large RadLex taxonomies and for curators to navigate the complex
terminology structure to check it for errors and omissions. In this work, we demonstrate that the RadLex terminology can be
translated into an ontology, a representation of terminologies that is both human-browsable and machine-processable. We also
show that creating this ontology permits computational analysis of RadLex and enables its use in a variety of computer applications.
We believe that adopting an ontology representation of RadLex will permit more widespread use of the terminology and make
it easier to collect feedback from the community that will ultimately lead to improving RadLex.
相似文献
Daniel L. RubinEmail: |
9.
Young U. Ryu John J. Buchanan 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,196(2):279-293
The coordination dynamics of learning were examined in a visuomotor tracking task. Participants produced rhythmic elbow flexion–extension
motions to learn a visually defined 90° relative phase tracking pattern with an external sinusoidal signal. There were two
visuomotor transformation groups, a correct feedback group and a mirrored feedback group with feedback representing the elbow’s
motion transformed by 180°. In Experiment 1, the to-be-tracked signal and the participant’s motion signal were superimposed
within a single window display. In Experiment 2, the to-be-tracked signal and participant’s signal were presented in separate
windows. Before day 1 practice and 24 h after day 2 practice, participants attempted visually defined 0°, 45°, 90°, 135°,
and 180° relative phase tracking patterns either with or without visual feedback of the arm’s motion. Before practice, only
the 0° and 180° tracking patterns were stable. Practice led to a decrease in phase error toward the required 90° relative
phase pattern with a corresponding increase in stability in both the experiments. No effect of visual transformation on performance
emerged during practice in the single window task, but did emerge in the two window task. The one window training facilitated
transfer to the four unpracticed relative phase patterns, whereas the two window training display only facilitated transfer
performance to a single unpracticed relative phase pattern. These findings suggest that the perceptual structure determined
the degree of learning and transfer and interacted with the visuomotor transformation. The present findings are discussed
with reference to how the visual display constrains the coherency of independent signals with regard to learning and transfer
and the role of perceptual discrimination processes linked to transfer.
相似文献
Young U. RyuEmail: |
10.
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: |
11.
Buonocore A McIntosh RD 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,191(1):117-122
The remote distractor effect is a robust finding whereby a saccade to a lateralised visual target is delayed by the simultaneous,
or near simultaneous, onset of a distractor in the opposite hemifield. Saccadic inhibition is a more recently discovered phenomenon
whereby a transient change to the scene during a visual task induces a depression in saccadic frequency beginning within 70 ms,
and maximal around 90–100 ms. We assessed whether saccadic inhibition is responsible for the increase in saccadic latency
induced by remote distractors. Participants performed a simple saccadic task in which the delay between target and distractor
was varied between 0, 25, 50, 100 and 150 ms. Examination of the distributions of saccadic latencies showed that each distractor
produced a discrete dip in saccadic frequency, time-locked to distractor onset, conforming closely to the character of saccadic
inhibition. We conclude that saccadic inhibition underlies the remote distractor effect.
相似文献
Robert D. McIntoshEmail: |
12.
Diederich A Colonius H 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,186(1):1-22
In a focused attention task saccadic reaction time (SRT) to a visual target stimulus (LED) was measured with an auditory (white
noise burst) or tactile (vibration applied to palm) non-target presented in ipsi- or contralateral position to the target.
Crossmodal facilitation of SRT was observed under all configurations and stimulus onset asynchrony (SOA) values ranging from
−500 (non-target prior to target) to 0 ms, but the effect was larger for ipsi- than for contralateral presentation within
an SOA range from −200 ms to 0. The time-window-of-integration (TWIN) model (Colonius and Diederich in J Cogn Neurosci 16:1000,
2004) is extended here to separate the effect of a spatially unspecific warning effect of the non-target from a spatially specific
and genuine multisensory integration effect.
相似文献
Hans ColoniusEmail: |
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.
Guy Madison Didier Delignières 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,193(4):519-527
Long-range dependence is a characteristic property of successively produced time intervals, such as in un-paced or continuation
tapping. We hypothesise in the present paper that serial dependence in such tasks could be related to a closed-loop regulation
process, in which the current interval is determined by preceding ones. As a consequence, the quality of sensory feedback
is likely to affect serial dependence. An experiment with human participants shows that diminished sensory information tends
to increase the Hurst exponent for short inter-onset intervals and tends to decrease it for long intervals. A simulation shows
that a simple auto-regressive model, whose order depends on the ratio between the inter-onset interval and an assumed temporal
integration span, is able to account for most of our empirical results, including the duration specificity of long-range correlation.
相似文献
Guy MadisonEmail: |
15.
Fuentes LJ Campoy G 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,185(4):667-672
In the present experiment we used a version of the attention network test (ANT) similar to that of Callejas et al. (Exp Brain
Res 167:27–37, 2005) to assess the Posner’s attention networks (alerting, orienting and conflict), and their interactions. We observed shorter
reaction times with alerting tone than with no alerting tone trials (the alerting effect); with cued than with uncued trials
(the orienting effect); and with congruent than with incongruent trials (the conflict effect). These results replicate previous
findings with the ANT. We also manipulated cue–target interval at five stimulus onset asynchrony (SOA) values (100, 300, 500,
800, and 1,200 ms) to trace the alerting network influence over the orienting network. The SOA manipulation showed that cuing
effects peaked at 300 ms SOA irrespective of whether an alerting tone was present or not, and the alerting tone improved the
cuing effect equally for 100–500 SOAs, but it did not at the longest 800–1,200 ms SOAs. These results suggest that alerting
improves rather than accelerates orienting effects, a result that agrees with data from neuropsychological rehabilitation
of parietal patients with spatial bias.
相似文献
Luis J. FuentesEmail: |
16.
Brandon N. Kyle Daniel W. McNeil Benjamin J. Weinstein James D. Mark 《Journal of behavioral medicine》2009,32(4):360-370
While stimulus intensity obviously affects degree of pain responding, presentation order effects of stimuli of different intensities
on acute pain responses are under-researched. The present study examined the effects of manipulating presentation order of
lower and higher pain stimulus intensity. Using 96 undergraduates, this investigation employed a 2 × 2 mixed research design,
with pain stimulus sequence as a between-subjects variable and pain stimulus trial as a repeated measure. When the greater
pain stimulus intensity was presented last, verbal report of pain was higher. Also, performance of a cognitive task was interrupted
the least when the lower stimulus intensity was presented last. Heart rate, however, was highest when the greater stimulus
intensity was presented first, and pain tolerance was greatest when the lower stimulus intensity was presented first. Results
are discussed in relation to adaptation-level effects, and implications for pain experienced in clinical settings are suggested.
相似文献
Daniel W. McNeilEmail: |
17.
J. S. Beymer E. Rudloff R. Kirby T. J. Novicki F. M. Moore 《Comparative clinical pathology》2009,18(3):279-281
To determine if 30- to 35-day-old units of canine stored whole blood held at room temperature over 24 h will reveal bacterial
contamination when exposed to repeated sampling. The design of the study is prospective, controlled. Ten units of stored whole
blood from ten client owned volunteer blood donor dogs were used. A sterile blood bag spike was inserted aseptically as a
port for repeated sampling for culture into ten separate units of 30- to 35-day-old canine stored whole blood held at room
temperature for 24 h. Aerobic and anaerobic bacterial culture samples were collected every 4 h over 24 h. No bacterial growth
was detected in any sample at any time point from the ten bags used. Canine stored whole blood, collected and stored for 30
to 35 days according to accepted transfusion guidelines, can be aseptically spiked and held at room temperature for 24 h without
evidence of bacterial contamination or proliferation.
相似文献
J. S. BeymerEmail: |
18.
Adam J. Strang William P. Berg Mathias Hieronymus 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,197(3):245-254
Muscle fatigue has been shown to result in early onset of anticipatory postural adjustments (APAs) relative to those produced
in a non-fatigued state. This adaptation is thought to reflect an attempt to preserve postural stability during a focal movement
performed in a fatigued state. It remains unclear, however, whether this adaptation is of central (e.g., central nervous system
motor command) or peripheral (e.g., muscle contractile properties), origin. One way to confirm that this adaptation is centrally
driven is to identify fatigued-induced early APA onsets in non-fatigued muscles. In this study, APAs were obtained using a
rapid bilateral reaching maneuver and recorded via surface electromyography before and after conditions of rest (n = 25) or fatigue (n = 25). Fatigue was generated using isokinetic exercise of the right leg. Results showed that fatigue-induced early APA onsets
occurred in fatigued and non-fatigued muscles, confirming that fatigue-induced early APA onset is a centrally mediated adaptation.
相似文献
William P. Berg (Corresponding author)Email: |
19.
I. Südhoff J. A. de Guise A. Nordez E. Jolivet D. Bonneau V. Khoury W. Skalli 《Medical & biological engineering & computing》2009,47(6):579-587
Patient-specific muscle geometry is not only an interesting clinical tool to evaluate different pathologies and treatments,
but also provides an essential input data to more realistic musculoskeletal models. The protocol set up in our study provided
the 3D-patient-specific geometry of the 13 main muscles involved in the knee joint motion from a few selected magnetic resonance
images (MRIs). The contours of the muscles were identified on five to seven MRI axial slices. A parametric-specific object
was then constructed for each muscle and deformed to fit those contours. The 13 muscles were obtained within 1 h, with less
than 5% volume error and 5 mm point-surface error (2RMS). From this geometry, muscle volumes and volumic fractions of asymptomatic
and anterior cruciate ligament deficient subjects could easily be computed and compared to previous studies. This protocol
provides an interesting precision/time trade-off to obtain patient-specific muscular geometry.
相似文献
W. Skalli (Corresponding author)Email: |
20.
John van der Kamp Hemke van Doorn Rich S. W. Masters 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,197(2):199-204
The present study addresses the role of vision for perception in determining the location of a target in far-aiming. Participants
(N = 12) slid a disk toward a distant target embedded in illusory Judd figures. Additionally, in a perception task, participants
indicated when a moving pointer reached the midpoint of the Judd figures. The number of hits, the number of misses to the
left and to the right of the target, the sliding error (in mm) and perceptual judgment error (in mm) served as dependent variables.
Results showed an illusory bias in sliding, the magnitude of which was comparable to the bias in the perception of target
location. The determination of target location in far-aiming is thus based on relative metrics. We argue that vision for perception
sets the boundary constraints for action and that within these constraints vision for action autonomously controls movement
execution, but alternative accounts are discussed as well.
相似文献
John van der KampEmail: |