共查询到20条相似文献,搜索用时 46 毫秒
1.
Research on the reception of health risk feedback has focused on the analysis of single, researcher-selected cognitive reactions.
The full range of spontaneous reactions and their patterns have received little attention. The present paper explores content,
interrelations, and adaptivity of spontaneous reactions to health risk feedback from a network perspective. Participants (n = 423) received blood pressure and cholesterol feedback and listed their thoughts afterwards. A network of reactions to health
risk feedback was constructed from the responses. Emotions, risk feedback valence, future lifestyle, and expectedness emerged
as strong and largely well-connected network nodes, while previously well-researched reactions like feedback acceptance formed
small, less connected nodes. The majority of reaction patterns identified through the network appeared adaptive, even after
negative feedback. The network provides a potentially useful tool for research and practice, highlighting previously neglected
relevant reactions, and providing a group-level background against which individual reactions can be evaluated.
相似文献
Britta Renner (Corresponding author)Email: |
2.
Sandra Sülzenbrück Herbert Heuer 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,195(1):153-165
Learning to operate a complex tool such as a sliding lever can be conceived as learning both a kinematic and a dynamic transformation.
We investigated whether the presence of the dynamic transformation has an inhibitory or a facilitative effect on learning
to control a sliding lever. Furthermore, we examined the characteristics of the internal model of the kinematic transformation
of the lever in visual open-loop trials. In the experiment, one group of participants practiced with only the kinematic transformation
of the lever (virtual lever), the other group practiced with both the kinematic and the dynamic transformation (physical lever).
Visual feedback was continuously present during practice. Results showed only marginal differences between both groups in
open-loop tests. This finding is likely to be related to the fact that in both groups a simplified approximation of the kinematic
transformation was acquired, in particular a symmetry approximation. With such an approximation the target for the hand movement
is derived from the visual target for the tip of the lever as the position which is symmetric around a sagittal axis.
相似文献
Sandra SülzenbrückEmail: |
3.
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: |
4.
Welber Marinovic Annaliese M. Plooy James R. Tresilian 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,197(4):311-319
Two experiments aimed to provide an estimate of the last moment at which visual information needs to be obtained in order
for it to be used to initiate execution of an interceptive movement or to withhold execution of such a movement. In experiment
1, we sought to estimate the minimum time required to suppress the movement when the participants were first asked to intercept
a moving target. In experiment 2, we sought to determine the minimum time required to initiate an interceptive movement when
the participants were initially asked to keep stationary. Participants were trained to hit moving targets using movements
of a pre-specified duration. This permitted an estimate of movement onset (MO) time. In both experiments the requirement to
switch from one prepared course of action to the other was indicated by changing the colour of the moving target at times
prior to the estimated MO. The results of the experiments showed that the decision to execute or suppress the interception
must be made no less than about 200 ms before MO.
相似文献
Welber MarinovicEmail: |
5.
Adaptations of lateral hand movements to early and late visual occlusion in catching 总被引:1,自引:1,他引:0
Dessing JC Wijdenes LO Peper CL Beek PJ 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,192(4):669-682
Recent studies suggested that the control of hand movements in catching involves continuous vision-based adjustments. More
insight into these adjustments may be gained by examining the effects of occluding different parts of the ball trajectory.
Here, we examined the effects of such occlusion on lateral hand movements when catching balls approaching from different directions,
with the occlusion conditions presented in blocks or in randomized order. The analyses showed that late occlusion only had
an effect during the blocked presentation, and early occlusion only during the randomized presentation. During the randomized
presentation movement biases were more leftward if the preceding trial was an early occlusion trial. The effect of early occlusion
during the randomized presentation suggests that the observed leftward movement bias relates to the rightward visual acceleration
inherent to the ball trajectories used, while its absence during the blocked presentation seems to reflect trial-by-trial
adaptations in the visuomotor gain, reminiscent of dynamic gain control in the smooth pursuit system. The movement biases
during the late occlusion block were interpreted in terms of an incomplete motion extrapolation—a reduction of the velocity
gain—caused by the fact that participants never saw the to-be-extrapolated part of the ball trajectory. These results underscore
that continuous movement adjustments for catching do not only depend on visual information, but also on visuomotor adaptations
based on non-visual information.
相似文献
Joost C. DessingEmail: |
6.
Heuer H Hegele M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,188(1):101-110
Adaptation to a novel visuo-motor gain has been found to generalize across target directions, whereas simultaneous adaptation
to different direction-related visuo-motor gains turned out to be impossible. We ask whether this is a rigid constraint on
human adaptability or a soft constraint that can be overcome by optimized conditions of practice. In particular, we compared
practice with continuous visual feedback, as used in previous studies, to practice with terminal visual feedback. With terminal
visual feedback only the final positions of the movements are shown. Both kinds of visual feedback in principle can serve
the acquisition of an internal model of direction-related visuo-motor gains, but with continuous feedback on-line visual closed-loop
control permits accurate movements without access to an internal model. Whereas we found no indication of visuo-motor adaptation
after continuous-feedback practice, there was adaptation after terminal-feedback practice. This was revealed both by (direction-related)
adaptive shifts of movement amplitudes in an open-loop test with cued visuo-motor transformation and by (direction-related)
aftereffects in an open-loop test with absence of the visuo-motor transformation being cued. None of the two groups gave evidence
of explicit knowledge of the direction-related visuo-motor gains. These findings show that constraints on human adaptability
can depend on the kind of experience with visuo-motor transformations, in particular on the kind of feedback during practice.
相似文献
Herbert HeuerEmail: |
7.
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: |
8.
Goal-directed reaching: movement strategies influence the weighting of allocentric and egocentric visual cues 总被引:3,自引:2,他引:1
Neely KA Tessmer A Binsted G Heath M 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,186(3):375-384
The location of an object in peripersonal space can be represented with respect to our body (i.e., egocentric frame of reference)
or relative to contextual features and other objects (i.e., allocentric frame of reference). In the current study, we sought
to determine whether the frame, or frames, of visual reference supporting motor output is influenced by reach trajectories
structured to maximize visual feedback utilization (i.e., controlled online) or structured largely in advance of movement
onset via central planning mechanisms (i.e., controlled offline). Reaches were directed to a target embedded in a pictorial
illusion (the induced Roelofs effect: IRE) and advanced knowledge of visual feedback was manipulated to influence the nature
of reaching control as reported by Zelaznik et al. (J Mot Behav 15:217–236, 1983). When vision could not be predicted in advance of movement onset, trajectories showed primary evidence of an offline mode
of control (even when vision was provided) and endpoints demonstrated amplified sensitivity to the illusory (i.e., allocentric)
features of the IRE. In contrast, reaches performed with reliable visual feedback evidenced a primarily online mode of control
and showed increased visuomotor resistance to the IRE. These findings suggest that the manner a reaching response is structured
differentially influences the weighting of allocentric and egocentric visual information. More specifically, when visual feedback
is unavailable or unpredictable, the weighting of allocentric visual information for the advanced planning of a reach trajectory
is increased.
相似文献
Matthew HeathEmail: |
9.
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: |
10.
Fraizer EV Suvobrata M Mitra S 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2008,185(3):429-441
Dual-task interactions in posture and cognitive tasks have been explained as a competition for spatial processing structures
or as interference in the online sensorimotor adjustments required for sensory integration. Going beyond these general terms
accounts, we propose that interference between spatial and temporal operations in posture–cognition arises at least partly
from the need to share a common behavioral context, such as a spatial frame of reference. Using immersive visualization and
motion-tracking techniques, we manipulated the spatial reference frames for a standing task and a conjunction visual search
task into or out of coincidence. Aside from performance trade-offs due to task-load manipulations, performing visual search
in a non-coincident reference frame led to cognitive task and postural task performance decrements (Experiment 1). Postural
dual-task decrements were also observed when visual search was split between coincident and non-coincident frames and both
frame conditions rendered identical in visual information relevant to posture control (Experiment 2). We concluded that the
postural control costs observed for posture–cognition dual-tasking may in part reflect costs of keeping tasks’ reference frames
in register.
相似文献
E. V. FraizerEmail: Email: |
11.
Alice G. Cruickshank Eugene McSorley 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,193(3):467-476
Identifying a stimulus as the target for a goal-directed movement involves inhibiting competing responses. Separable inhibitory
interconnections bias local competition to ensure only one stimulus is selected and to alter movement initiation. Behavioural
evidence of these inhibitory processes comes from the effects of distracters on oculomotor landing positions and saccade latencies.
Here, we investigate the relationship between these two sources of inhibition. Targets were presented with or without close
and remote distracters. In separate experiments the possible position and identity of the target and distracters were manipulated.
In all cases saccade landing position was found to be less affected by the presence of the close distracter when remote distracters
were also present. The involuntary increase in the latency of saccade initiation caused by the presence of the remote distracters
alters the state of competitive processes involved in selecting the saccade target thus changing its landing position.
相似文献
Alice G. CruickshankEmail: |
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.
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: |
14.
Myrka Zago Joseph McIntyre Patrice Senot Francesco Lacquaniti 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,192(4):571-604
Intercepting and avoiding collisions with moving objects are fundamental skills in daily life. Anticipatory behavior is required
because of significant delays in transforming sensory information about target and body motion into a timed motor response.
The ability to predict the kinematics and kinetics of interception or avoidance hundreds of milliseconds before the event
may depend on several different sources of information and on different strategies of sensory-motor coordination. What are
exactly the sources of spatio-temporal information and what are the control strategies remain controversial issues. Indeed,
these topics have been the battlefield of contrasting views on how the brain interprets visual information to guide movement.
Here we attempt a synthetic overview of the vast literature on interception. We discuss in detail the behavioral and neurophysiological
aspects of interception of targets falling under gravity, as this topic has received special attention in recent years. We
show that visual cues alone are insufficient to predict the time and place of interception or avoidance, and they need to
be supplemented by prior knowledge (or internal models) about several features of the dynamic interaction with the moving
object.
相似文献
Francesco LacquanitiEmail: |
15.
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: |
16.
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: |
17.
Taeko Harada Ichiro Miyai Mitsuo Suzuki Kisou Kubota 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,195(3):445-454
When participants reach for a target, their hand can adjust to a change in target position that occurs while their eyes are
in motion (the hand’s automatic pilot) even though they are not aware of the target’s displacement (saccadic suppression of
perceptual experience). However, previous studies of this effect have displayed the target without interruption, such that
the new target position remains visible during the fixation that follows the saccade. Here we test whether a change in target
position that begins and ends during the saccade can be used to update aiming movements. We also ask whether such information
can be acquired from two targets at a time. The results showed that participants responded to single and double target jumps
even when these targets were extinguished prior to saccade termination. The results imply that the hand’s automatic pilot
is updated with new visual information even when the eye is in motion.
相似文献
Romeo ChuaEmail: |
18.
Richard T. Dyde Michael R. Jenkin Heather L. Jenkin James E. Zacher Laurence R. Harris 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,194(4):647-660
We measured the effect of the orientation of the visual background on the perceptual upright (PU) under different levels of
gravity. Brief periods of micro- and hypergravity conditions were created using two series of parabolic flights. Control measures
were taken in the laboratory under normal gravity with subjects upright, right side down and supine. Participants viewed a
polarized, natural scene presented at various orientations on a laptop viewed through a hood which occluded all other visual
cues. Superimposed on the screen was a character the identity of which depended on its orientation. The orientations at which
the character was maximally ambiguous were measured and the perceptual upright was defined as half way between these orientations.
The visual background affected the orientation of the PU less when in microgravity than when upright in normal gravity and
more when supine than when upright in normal gravity. A weighted vector sum model was used to quantify the relative influence
of the orientations of gravity, vision and the body in determining the perceptual upright.
相似文献
Richard T. DydeEmail: |
19.
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: |
20.
Scott Sinnett Janice J. Snyder Alan Kingstone 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,194(2):191-196
We demonstrate that attention to object representations is vitally dependent on the prefrontal cortex. Object-based selective
attention was compared in neurologic patients with unilateral damage to either the dorsolateral prefrontal cortex (DLPFC)
or the parietal cortex and in healthy controls. Our task required a top–down attentional modulation of object representations
in which spatial location played no role. All groups could invoke top–down object-based selection, but the DLPFC patients
showed a selective deficit when target stimuli were in the hemifield contralateral to the lesioned hemisphere. Our findings
indicate that in the healthy brain, anterior cortical mechanisms are crucial for attending to object-centered representations,
whereas posterior cortical mechanisms are necessary for attending to objects at locations in the visual scene.
相似文献
Scott SinnettEmail: |