共查询到20条相似文献,搜索用时 78 毫秒
1.
R. V. Flores C. A. Souza N. M. Ocarino V. A. Gheller M. J. Lopes M. S. Palhares R. Serakides 《Comparative clinical pathology》2006,15(3):131-142
Sixteen male Holstein calves, from 1 to 9 days old, were used in the study. The purpose was to compare the effect of both hypertonic (NaCl at 7.2%, 2,400 mOsm/l) and isotonic (NaCl at 0.9%, 300 mOsm/l) saline solutions associated with oral rehydrating solution, using the serum biochemical profile, serum and urinary osmolality, and electrolytic renal clearance and excretion in neonate calves with osmotic diarrhea-induced dehydration. Calves were randomly distributed into four groups: group 1, normal; group 2, treatment with hypertonic saline plus oral solution; group 3, treatment with isotonic saline plus oral solution; and group 4, with no treatment (diarrhea control group). Animals with no treatment presented aqueous diarrhea, severe hyponatremia, hypochloremia, hypokalemia, decrease of rhythm of glomerular filtration, hyperphosphatemia, and azotemia. The use of small volumes of hypertonic saline solution in a single dose restored the plasma volume, serum sodium and chloride concentrations, and rhythm of glomerular filtration. When compared to isotonic saline, hypertonic saline brought about a less marked hemodilution and reestablished serum potassium concentration and rhythm of glomerular filtration. The use of large volumes of isotonic saline solution is associated with a higher rhythm of glomerular filtration, larger hemodilution, and urinary losses of sodium and chloride. We conclude that a rapid infusion of small volumes of hypertonic saline solution with oral rehydrating solution immediately increases plasma volume, serum osmolality, sodium and chloride seric concentrations, rhythm of glomerular filtration, urinary flow, restoring the volume of extracellular fluid after 24 h constituting a practical and economical alternative to the use of large volumes of isotonic saline solution.
相似文献
R. SerakidesEmail: Phone: +55-31-34992229Fax: +55-31-34992230 |
2.
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: |
3.
William P. Sacco John I. Malone Anthony D. Morrison Andrea Friedman Kristen Wells 《Journal of behavioral medicine》2009,32(4):349-359
Brief, cost-effective interventions to promote diabetes self-management are needed. This study evaluated the effects of a
brief, regular, proactive, telephone “coaching” intervention delivered by paraprofessionals on diabetes adherence, glycemic
control, diabetes-related medical symptoms, and depressive symptoms. Therapeutic mechanisms underlying the intervention’s
effect on the primary outcomes were also examined. Adults diagnosed with type 2 diabetes (N = 62) were randomly assigned to receive the “coaching” intervention and treatment as usual, or only treatment as usual. The
intervention increased frequency of exercise and feet inspection, improved diet, reduced diabetes medical symptoms, and lowered
depressive symptoms. Self-efficacy, reinforcement, and awareness of self-care goals mediated the treatment effect on depression,
exercise, and feet inspection, respectively. A brief telephone intervention delivered by paraprofessionals had positive effects
on type 2 diabetes patients.
相似文献
William P. SaccoEmail: |
4.
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: |
5.
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: |
6.
Alexis D. J. Makin Andrew J. Stewart Ellen Poliakoff 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,193(1):137-142
Previous work indicates that extrapolation of object motion during occlusion is affected by the velocity of the immediately
preceding trial. Here we ask whether longer-term velocity representations can also influence motion extrapolation. Red, blue
or green targets disappeared behind an occluder. Participants pressed a button when they thought the target had reached the
other side. Red targets were slower (10–20 deg/s), blue targets moved at medium velocities (14–26 deg/s) and green targets
were faster (20–30 deg/s). We compared responses on a subset of red and green trials which always travelled at 20 deg/s. Although
trial velocities were identical, participants responded as if the green targets moved faster (M = 22.64 deg/s) then the red targets (M = 19.72 deg/s). This indicates that motion extrapolation is affected by longer-term information about the typical velocity
of different categories of stimuli.
相似文献
Ellen PoliakoffEmail: |
7.
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: |
8.
Young SJ Pratt J Chau T 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,192(1):121-132
Research has suggested that prospective motor decisions are consistent with actual motor action. In a study that we recently
published (Young et al. in Exp Brain Res 185:681–688, 2008), however, participants demonstrated a preference for closer targets that was inconsistent with the predictions of Fitts’s
law. With a pair of experiments, the present paper investigates the underlying basis of this non-optimal behaviour. Participants
showed a similar deviation from Fitts’s law when imagining movements—believing that movement duration increased with distance
within the same index of difficulty. Participants did not behave similarly, however, in a perceptual version of the decision
task. These results suggest that imagined movements and motor decisions are linked, as well as demonstrating one situation
in which both show a similar deviation from the patterns of actual movement duration.
相似文献
Scott J. YoungEmail: |
9.
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: |
10.
Lawrence E. M. Grierson Digby Elliott 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,197(3):279-285
This experiment was designed to determine if real and illusory shifts in target position at movement initiation affect the
same online corrective processes. Adult participants completed rapid goal-directed movements toward the vertex of a target
“T” located at the midline, 25 cm distal to a small home position. At movement initiation, the target either stayed the same,
shifted its real position, its illusory position or both. The real perturbation involved a 2.5 mm shift either toward or away
from the body. For the illusory perturbation, the horizontal portion of the “T” changed to inward or outward Müller–Lyer wings. Both the real and the illusory perturbation affected movement outcome. The
two manipulations began to have their impact at peak velocity. Because both perturbations affected mid to late trajectory
control and because their effects were not independent, we concluded that real and illusory target shifts impact late visual
motor control associated with a comparison between the position of the limb and the perceived position of the target.
相似文献
Lawrence E. M. GriersonEmail: |
11.
Matthew R. Longo Bennett I. Bertenthal 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,192(4):739-744
The perception of actions performed by others activates one’s own motor system. Recent studies disagree as to whether this
effect is specific to actions performed by other humans, an issue complicated by differences in perceptual salience between
human and non-human stimuli. We addressed this issue by examining the automatic imitation of actions stimulated by viewing
a virtual, computer-generated, hand. This stimulus was held constant across conditions, but participants’ attention to the
virtualness of the hand was manipulated by informing some participants during instructions that they would see a “computer-generated
model of a hand,” while making no mention of this to others. In spite of this attentional manipulation, participants in both
conditions were generally aware of the virtualness of the hand. Nevertheless, automatic imitation of the virtual hand was
significantly reduced––but not eliminated––when participants were told they would see a virtual hand. These results demonstrate
that attention modulates the “human bias” of automatic imitation to non-human actors.
相似文献
Matthew R. LongoEmail: |
12.
Although respiratory sinus arrhythmia (RSA) is a well-known and often studied phenomenon, methods to estimate (average) respiratory
rate from heart rate variability via RSA have been investigated and published only sparsely. We reinvestigate three published
techniques and contrast them to our own approaches. All methods were also evaluated for respiration signals to yield approximations
of the true breathing rate for comparison. Our analyses are based on physiological recordings available at PhysioNet, an online
database. Results show that the RSA of young supine subjects yields good approximations of mean respiratory rate in the case
of time series longer than 1 min, while the estimations become noticeably less accurate for elderly persons. Our own “advanced
counting method” produced the best results, and in addition principally permits even the definition of instantaneous respiratory
rates. Consequently, it is recommended for further investigations.
相似文献
Karl W. KratkyEmail: |
13.
Robert A. Fenton 《Pflügers Archiv : European journal of physiology》2009,458(1):169-177
Movement of urea across plasma membranes is modulated by specialized urea transporter proteins. Two urea-transporter genes
have been cloned: UT-A (Slc14a2) and UT-B (Slc14a1). In the mammalian kidney, urea transporters are essential for the urinary concentrating mechanism and maintaining body fluid
homeostasis. In this article, we discuss (1) an overview of historic discoveries in urea transport mechanisms; (2) an overview
of recent discoveries in the regulation of urea transporters; (3) physiological studies in UT-A1/3
−/− mice highlighting the essential role of urea transporters in the urinary concentrating mechanism; and (4) physiological studies
in UT-A2 and UT-B knockout mice examining the role of countercurrent exchange in the production of a maximally concentrated
urine.
相似文献
Robert A. FentonEmail: |
14.
Masked priming experiments are frequently used to study automatic aspects of word processing. Direct measures of such processing
obtained with functional neuroimaging techniques (ERPs, fMRI, etc.) need to isolate the neural activation related to relevant
events when they are rapidly followed by others (a situation found in other popular paradigms such as the attentional blink
and repetition blindness). Here we examine the assumption of “simple insertion”, which underlies the use of subtraction to
isolate components of temporally overlapping waveforms. We propose two novel linear methods and illustrate how they extract
temporal and spatial ERP components that the subtraction method fails to detect. We show this through the analysis of ERP
data from a masked semantic priming procedure. The new techniques reveal activation generated by unconscious (masked) prime
words as early as 100 ms and 200 ms post stimulus-onset; a pattern which simple subtraction fails to detect.
相似文献
Andrés CatenaEmail: |
15.
Arning L Monté D Hansen W Wieczorek S Jagiello P Akkad DA Andrich J Kraus PH Saft C Epplen JT 《Journal of molecular medicine (Berlin, Germany)》2008,86(4):485-490
Huntington’s disease (HD) is an autosomal dominantly inherited neurodegenerative disease associated with abnormal expansions
of a stretch of perfect CAG repeats in the HD gene. The number of repeat units is predictive for the age at onset (AO) of neurological symptoms. Part of the remaining
variation in AO is attributed to modifier genes. In this study, genes involved in apoptosis were investigated as candidates
for modulating AO in HD. A panel of 304 candidate genes was screened for allelic associations with motor AO via linked micro-satellite
markers by pooling the DNAs of HD individuals from opposite ends of the AO distribution. After genotyping promising markers
from the pooling experiment individually, markers revealed consolidated evidence for association in a candidate region comprising
the genes MAP3K5 (ASK1)/PEX7 at 6q23.3 and in the gene MAP2K6 at 17q24.3. Fine-mapping of these candidate regions in a cohort of 250 Caucasian HD patients using single nucleotide polymorphism
(SNP) markers delimitated the precise locations of association. Certain variations in an ASK1–PEX7 haplotype block explain 2.6% of additional variance in AO in our HD cohort. In males, 4.9% additional variance could be attributed
to MAP2K6 genotype variations. Altogether, ASK1–PEX7 haplotypes and MAP2K2 genotype variations explain 6.3% additional variance in AO for HD. We hypothesise that sequence variations of ASK1 and MAP2K6 lead to partially sex-specific changes in the levels and/or phosphorylation states of p38 and p38-regulated proteins that
might contribute to the observed delaying effects in the AO of HD.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Larissa ArningEmail: |
16.
Li WG Luo XY Chin SB Hill NA Johnson AG Bird NC 《Annals of biomedical engineering》2008,36(11):1893-1908
Bile flow is thought to play an essential role in the pathophysiological genesis of cholelithiasis (gallstone formation) and
in gallbladder pain. In this paper, we extend our previous study of the human biliary system (Li et al., 2007, J. Biomech. Eng., 129:164–173) to include two important factors: the non-Newtonian properties of bile, and elastic deformation of the cystic
duct. A one-dimensional (1D) model is analyzed and compared with three-dimensional (3D) fluid–structure interaction simulations.
It is found that non-Newtonian bile raises resistance to the flow of bile, which can be augmented significantly by the elastic
deformation (collapse) of the cystic duct. We also show that the 1D model predicts the pressure drop of the cystic duct flow
well for all cases considered (Newtonian or non-Newtonian flow, rigid or elastic ducts), when compared with the full 3D simulations.
相似文献
X.Y. LuoEmail: |
17.
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: |
18.
Cysarz D Zerm R Bettermann H Frühwirth M Moser M Kröz M 《Annals of biomedical engineering》2008,36(12):2085-2094
It would often be desirable to obtain the respiratory rate during everyday conditions without obtaining an additional respiratory
trace. This study investigates the agreement between respiratory rate assessed from the electrocardiogram (ECG) and the reference
respiratory rate derived from a nasal/oral airflow (AF). Nasal/oral airflow and a Holter ECG were recorded in 52 healthy subjects
(26 males, age range: 25.4–85.4 years) during everyday conditions for at least 10 h, including night-time sleep. The respiratory
rate was assessed for each 5-min epoch (1) using respiratory sinus arrhythmia (RSA), (2) utilizing the respiration induced
variations of the R-wave amplitude (ECG derived respiration (EDR)). The agreement with respect to AF was quantified using
the average/std and the concordance correlation coefficient ρc. For RSA and EDR the difference with respect to AF was 0.2 cpm (std: 0.6 cpm) during sleep and −0.2 cpm (std: 1.0 cpm) during
wake time. During sleep the RSA-approach performed best for subjects ≤50 years (ρc = 0.79) and worst for subjects >50 years (ρc = 0.41). The correlation of the EDR-approach was ρc = 0.73 for both groups. In conclusion, the respiratory rate may be assessed with reasonable agreement by both methods in
younger subjects, but EDR should be preferred in the elderly.
相似文献
Dirk CysarzEmail: |
19.
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: |
20.
Dana Maslovat Anthony N. Carlsen Romeo Chua Ian M. Franks 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2009,195(3):383-392
For synchronous bimanual movements, we have shown that a different amplitude can be prepared for each limb in advance and
this preparation improves with practice (Maslovat et al. 2008). In the present study, we tested whether an asynchronous bimanual movement can also be prepared in advance and be improved
with practice. Participants practiced (160 trials) a discrete bimanual movement in which the right arm led the left by 100 ms
in response to an auditory “go” signal (either 80 dB control stimulus or 124 dB startle stimulus). The startle stimulus was
used to gauge whether inter-limb timing could be pre-programed. During startle trials, the asynchronous bimanual movement
was triggered at early latency suggesting the entire movement could be prepared in advance. However, the triggered movement
had a shorter between-arm delay and a temporally compressed within-arm EMG pattern, results that we attribute to increased
neural activation caused by the startling stimulus. However, as both startle and control trials improved over time, it does
appear response preparation of interval timing can improve with practice.
相似文献
Ian M. Franks (Corresponding author)Email: |