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At least 667 records · Page 37Linked to original sources

PubMed2006

Regulation of tentacle length in snails by odor concentration.

The upper tentacle of the snail, bearing the olfactory organ, produces complex movements when the snail explores a new environment. Tentacle trajectories were reconstructed in the presence and absence of odors using two simultaneous video recordings. Reconstructions showed that in the absence of odor, snails constantly scanned the surrounding space with the extended tentacles. Presentation of an odor elicited rapid flexion, independent of the odor concentration, accompanied by concentration-dependent tentacle contractions. Activation of identified motoneuron MtC3 is known to elicit tentacle contraction. Recordings made in semi-intact preparations showed that the dynamics and duration of the spike activity of MtC3 produced in response to odors correlated with the degree of tentacle contraction in response to odors. These data suggest that the central motoneuron MtC3, which triggers tentacle contraction, is involved in controlling the margins of the scanning field. Slow contraction or extension of the tentacle, associated with the level of MtC3 activity, may operate to tune the snail's investigative behavior to the conditions of the sensory environment.

Action Potentials↗

PubMed2006

Effects of alcohol on group formation among male social drinkers.

OBJECTIVE: Social factors affect alcohol use and misuse, yet researchers rarely study the acute effects of alcohol in groups. This study used systematic observation techniques to measure the effects of alcohol on behavioral responses during an initial group interaction. METHOD: Fifty-four male social drinkers were assembled into three-person groups of strangers, and all members of each group were administered either a 0.82 g/kg dose of alcohol or a placebo to be consumed during a 30-minute period. This social interaction was video recorded, and the duration and sequence of selected smiling and speech behaviors were coded on a 1-second time base. RESULTS: Alcohol consumption increased individual- and group-level coordination of smiling and speech behaviors over time and improved self-reported bonding. CONCLUSIONS: These data suggest that alcohol may facilitate social bonding during initial group formation. Measuring behavioral responses in a social context provides new directions for studying the acute effects of alcohol.

Adult↗

PubMedDate not supplied

Interactive image analysis system to determine the motility and velocity of cyanobacterial filaments.

An interactive image analysis system has been developed to analyse and quantify the percentage of motile filaments and the individual linear velocities of organisms. The technique is based on the "difference" image between two digitized images taken from a time-lapse video recording 80 s apart which is overlaid on the first image. The bright lines in the difference image represent the paths along which the filaments have moved and are measured using a crosshair cursor controlled by the mouse. Even short exposure to solar ultraviolet radiation strongly impairs the motility of the gliding cyanobacterium Phormidium uncinatum, while its velocity is not likewise affected. These effects are not due to either type I (free radical formation) or type II (singlet oxygen production) photodynamic reactions, since specific quenchers and scavengers, indicative of these reactions, failed to be effective.

Cell Movement↗

PubMed2004

Learning effect of a novel interactive basic life support CD: the JUST system.

INTRODUCTION: Electronic interactive learning environments can enhance the learning experience and may prove beneficial in basic life support (BLS) training. As part of the European Union funded project "JUST-in-time health emergency interventions-training of non-professionals by virtual reality and advanced IT tools", an innovative interactive CD-ROM on BLS and other emergency medicine topics was developed. We hypothesised that individuals without previous BLS training could learn CPR techniques from this CD. METHODS: Sixty-two students were randomised into a group studying the JUST CD in a computer class room for up to 60 min, and a control group who did not receive any training (serving as a reference). CD users also completed a satisfaction questionnaire immediately after studying the CD. The BLS skills of both groups were assessed in a mock BLS scenario on a training manikin. BLS performance was video recorded and analysed. RESULTS: After studying the CD for a mean period of 42 min, users of the CD had better assessment skills and were more likely to show a positive helping attitude, but chest compression and breathing techniques were ineffective. Most users rated the CD as very good and a positive learning tool. CONCLUSION: Individuals without prior BLS training showed improved behaviour and assessment skills after exposure to the CD, but motor skill acquisition requires alternative learning strategies.

CD-ROM↗

PubMed1991

Determination of ciliary polarity precedes differentiation in the epithelial cells of quail oviduct.

In quail oviduct epithelium, as in all metazoan and protozoan ciliated cells, cilia beat in a coordinated cycle. They are arranged in a polarized pattern oriented according to the anteroposterior axis of the oviduct and are most likely responsible for transport of the ovum and egg white proteins from the infundibulum toward the uterus. Orientation of ciliary beating is related to that of the basal bodies, indicated by the location of the lateral basal foot, which points in the direction of the active stroke of ciliary beating. This arrangement of the ciliary cortex occurs as the ultimate step in ciliogenesis and following the oviduct development. Cilia first develop in a random orientation and reorient later, simultaneously with the development of the cortical cytoskeleton. In order to know when the final orientation of basal bodies and cilia is determined in the course of oviduct development, microsurgical reversal of a segment of the immature oviduct was performed. Then, after hormone-induced development and ciliogenesis, ciliary orientation was examined in the inverted segment and in normal parts of the ciliated epithelium. In the inverted segment, orientation was reversed, as shown by a video recording of the direction of effective flow produced by beating cilia, by the three-dimensional bending forms of cilia immobilized during the beating cycle and screened by scanning electron microscopy, and by the position of basal body appendages as seen in thin sections by transmission electron microscopy. These results demonstrate that basal body and ciliary orientation are irreversibly determined prior to development by an endogenous signal present early in the cells of the immature oviduct, transmitted to daughter cells during the proliferative phase and expressed at the end of ciliogenesis.

Animals↗

PubMed2007

Evidence of early development of action planning in the human foetus: a kinematic study.

The aim of the present study was to investigate whether foetal hand movements are planned and how they are executed. We performed a kinematic analysis of hand movements directed towards the mouth and the eyes in the foetuses of eight women with normally evolving pregnancies. At 14, 18 and 22 weeks of gestation, eight foetuses underwent a 20-min four-dimensional-ultrasound session. The video recordings for these movements were then imported into in-house software developed to perform kinematic analysis. We found that spatial and temporal characteristics of foetal movements are by no means uncoordinated or unpatterned. By 22 weeks of gestation the movements seem to show the recognizable form of intentional actions, with kinematic patterns that depend on the goal of the action, suggesting a surprisingly advanced level of motor planning.

Adult↗

PubMed2005

Eye velocity asymmetry, ocular orientation, and convergence induced by angular rotation in the rabbit.

We studied ocular asymmetries and orienting responses induced by angular rotation in rabbits with binocular video recordings. Slow phase velocities were significantly larger in the eye moving temporonasally than nasotemporally. The eyes also converged and pitched down during rotation, which increased and refocused binocular overlap in the visual fields. Eye position also shifted into the slow phase direction. Vergence and pitch outlasted the induced nystagmus, suggesting that they were generated by a separate vestibulo-oculomotor subsystem(s). Thus, mechanisms in the rabbit increase compensatory eye velocity in the eye that leads into the direction of rotation and enhance binocular vision.

Animals↗

PubMed2006

Rotational feeding in caecilians: putting a spin on the evolution of cranial design.

Caecilians are a poorly known group of amphibians with a highly derived skull and cranial musculature that has evolved in response to their specialized head-first burrowing lifestyle. They possess a unique jaw-closing system, which is shown to be capable of generating considerable bite forces for its head width (1.09+/-0.34 and 0.62+/-0.31 N for Schistometopum thomense and Boulengerula taitanus, respectively). However, comprehensive dietary studies indicate that there is no need for large bite forces, since most caecilians appear to be generalist predators of subterranean macrofauna. Here, we demonstrate, based on in vivo external and X-ray video recordings of animals feeding, that long-axis body rotations are used independent of prey size by these two species of caeciliid caecilians when feeding underground. Further, we show that individuals are capable of generating a substantial spinning force, which is greater than their bite force (1.35+/-0.26 and 1.02+/-0.18 N, respectively). These observations shed light on the functional and the evolutionary significance of several unique features of the cranial design in derived caecilians; spinning may allow the individuals to judge prey size and subsequently reduce oversized prey within gape limits.

Amphibians↗

PubMed1999

Complete compensation in skilled reaching success with associated impairments in limb synergies, after dorsal column lesion in the rat.

Each of the dorsal columns of the rat spinal cord conveys primary sensory information, by way of the medullary dorsal column nucleus, to the ventrobasal thalamus on the contralateral side; thus the dorsal columns are an important source of neural input to the sensorimotor cortex. Damage to the dorsal columns causes impairments in synergistic proximal or whole-body movements in cats and distal limb impairments in primates, particularly in multiarticulated finger movements and tactile foviation while handling objects, but the behavioral effects of afferent fiber lesions in the dorsal columns of rodents have not been described. Female Long-Evans rats were trained to reach with a forelimb for food pellets and subsequently received lesions of the dorsomedial spinal cord at the C2 level, ipsilateral to their preferred limb. Reaching success completely recovered within a few days of dorsal column lesion. Nevertheless, a detailed analysis of high-speed video recordings revealed that rotatory limb movements (aiming, pronation, supination, etc.) were irreversibly impaired. Compensation was achieved with whole-body and alternate limb movements. These results indicate the following: (1) in the absence of the dorsal columns, other sensorimotor pathways support endpoint success in reaching; (2) sensory input conveyed by the dorsal columns is important for both proximal and distal limb movements used for skilled reaching; and (3) detailed behavioral analyses in addition to endpoint measures are necessary to completely describe the effects of dorsal column lesions.

Animals↗

PubMedDate not supplied

Infant response to mother call patterns in Otolemur garnettii.

Garnett's greater bushbaby infants vocalize in apparent response to their mother's contact calls. However, it remains unclear whether specific vocal or behavioral patterns by a mother elicit this vocal response. We video-recorded the behaviors and vocalizations of 4 individual mother-infant groups (mother with twins), analyzed vocalizations via spectrography and documented behaviors of mothers and infants. Initial analyses of all groups revealed that short growls and short growl bouts (or chains), but not long growls, emitted by mothers, were followed by infant clicks within 5 s. Further statistical examination of 1 mother-infant group revealed that an infant's vocal response is conditional on the sequencing of the mother's short growls and somewhat conditional on the mother's behavior before or after the short growls.

Animal Communication↗

PubMed1991

Influence of basement membrane molecules on directional migration of human breast cell lines in vitro.

Spheroidal cell aggregates were prepared from four tumorigenic human breast cell lines (HBL-100 and three MCF-7 variants). Cells from these aggregates were allowed to migrate towards lanes of basement membrane components coated on a glass substratum. Matrigel (reconstituted basement membrane) lanes permanently arrested the migration of one MCF-7 cell line, while migration of the others was permitted. Amongst several purified basement membrane constituents only laminin, not collagen type IV or fibronectin, was found to cause the same arrest of migration. Within the laminin molecule only the pepsin P1, not the elastase E8 fragment, efficiently arrested migration of that cell line. Although migration was inhibited by these components, time-lapse video recordings revealed that arrested cells still proliferated and actively ruffled on top of the coatings. These data suggest that, amongst several basement membrane components, laminin can function as a stop signal for cell migration. Within laminin, this activity seems to be mainly associated with the P1 fragment. We conclude that laminin is the major determinant of the barrier-function of the basement membrane, to which some cell types have become insensitive.

Basement Membrane↗

PubMedDate not supplied

Brain imaging during seizure: ictal brain SPECT.

The role of single photon computed tomography (SPECT) in presurgical localization of medically intractable complex partial epilepsy (CPE) in children is reviewed. 99mTechnetium Neurolite, a newer lipophylic agent with a high first pass brain extraction and little or no redistribution is injected during a seizure, while the child is monitored with a video recording and continuous EEG and SPECT imaging is performed in the next 1-3 hours with the images representing regional cerebral profusion at the time of injection. On SPECT studies performed with radiopharmaceutical injected during a seizure, ictal focus is generally hypervascular. Other findings on ictal brain SPECT include hypoperfusion of adjacent cerebral cortex and white matter, hyperperfusion of contralateral motor cortex, hyperperfusion of ipsilateral basal ganglia and thalamus, brain stem and contralateral cerebellum. Ictal brain SPECT is non-invasive, cost effective and highly sensitive for localization of epileptic focus in patients with intractable CPE.

Brain↗

PubMed2005

Chewing indicators between adults with Down syndrome and controls.

Down syndrome induces a neuromotor deficiency that affects the orofacial musculature, and thus could be implicated in the feeding difficulties affecting people with this disease. This study aimed to investigate the differences in chewing indicators between a group of 11 adults with Down syndrome and a group of 12 healthy subjects without Down syndrome. Chewing ability was evaluated by means of video recordings taken during a standardized meal that included 10 natural foods. The variables collected were masticatory time, number of masticatory cycles, chewing frequency, number of open masticatory cycles, and number of food refusals. There were several differences in both directions for masticatory time and number of masticatory cycles between the two groups. In addition, with the exception of purée, the group with Down syndrome had significantly lower mean chewing frequency than the reference group, and was unable to eat all the foods presented.

Adolescent↗

PubMed1991

A computer-video aided time motion analysis technique for match analysis.

The purpose of this study was to find out suitable methods for obtaining objective data on the time spent by players of different positions during walking, jogging, cruising, sprinting and standing still during match play activities. Computer programs and filming analyses with a simple notation system based upon symbolic representations of movements have been devised for analysis of individual players' behaviour. A technique was devised and employed with a small group of university players, aged 19-21 years of age. The subjects were filmed in several matches, and the video recordings were analysed using a microcomputer. The ratio of the time spent for the players were 56% walking, 30% jogging, 4% cruising, 3% sprinting and 7% standing still. ANOVA revealed that there are significant differences among the players for different positions on the field, for example the time spent on walking, jogging and standing still differed (P less than 0.05) among attackers, defenders and midfielders. A new method has been developed to obtain reliable information about the players' movement and performance in the game. The Authors believe that there should be further studies carried out involving more teams at different levels of performance to substantiate these preliminary findings.

Adult↗

PubMed1989

A quantitative study of fluorescein isothiocyanate-dextran transport in the microcirculation of the isolated perfused rat liver.

Hepatic extraction of solutes depends on microvascular angioarchitecture, hemodynamics and solute concentrations. These factors may contribute to the heterogeneity observed in solute transport and uptake in the hepatic lobules. However, predictions of liver extraction based on black-box models require assumptions about these factors and the microvascular transport mechanisms involved. Consequently, the purpose of this study was to investigate solute transport and uptake by hepatocytes. Livers from male Sprague-Dawley rats were perfused at physiological flowrates and portal pressures on the stage of an in vivo microscope using a low-hematocrit Ringer solution. A bolus of fluorescein isothiocyanate-dextrans (17,900, 39,000, 65,600 or 156,900 MW), which are considered inert fluid-phase markers, was injected into the portal vein. Fluorescein isothiocyanate fluorescence, as a measure of solute concentration, was video recorded in periportal or centrivenular regions of the lobules. Spatial and temporal fluorescence data, measured in sinusoids and hepatocytes, were fit to one-dimensional transport models to determine estimates for an intracellular effective diffusion coefficient and for hepatocyte permeability. The calculated effective diffusion coefficients were 2.5 times larger for dextrans less than 66,000 MW, but were not different between the periportal and centrivenular regions. Also, the values did not show the inverse log-log molecular weight dependency for dextrans seen in other microvascular tissues.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2004

Laryngeal adduction asymmetries in normal speaking subjects.

To investigate the prevalence of asymmetries at vocal fold adduction, 109 vocally healthy subjects between 22 and 80 years of age were examined. All subjects were examined with a rigid endoscope and video recorded. The recordings were analysed off line by two laryngologists. Seventy percent of the subjects displayed some kind of asymmetry. There was no difference between the sexes. Side differences in antero-posterior position of the corniculate or cuneiform tubercles were the most frequent asymmetries, occurring in 66% of the total material and in 92% of the asymmetrical cases. Asymmetries appeared more common and more marked in older subjects and possibly more frequent in singers than in non-singers. Laryngeal adduction asymmetries are probably of little importance for voice function.

Adult↗

PubMed1990

Characterization of the dynamic nature of microglial cells.

Dynamic properties of ramified microglia were investigated in tissue cultures of rat brain cells. Microglia were identified in viable cultures based on previously determined aspects of their morphology and location, and this identification was confirmed through immunohistochemical staining for type-three complement receptors. When living microglial cells were monitored using time-lapse video recording, an extremely dynamic nature was revealed. These cells exhibited morphological alteration, surface and cytoplasmic activity, and migration. All of these properties were both constant and rapid, with individual cells being capable of assuming a completely different overall morphology within a period as short as 5-10 min. These dynamic properties were consistently observed in microglia and appeared specific to this cell type. Thus, ramified microglia appear to possess a unique and highly dynamic nature, and this feature is proposed as a potential marker for these cells. Additionally, the significance of microglial cellular dynamics in the functional role of this cell population in vivo is considered.

Animals↗

PubMedDate not supplied

Behavior of arterial wall cells cultured on periodically stretched substrates.

Cells in vital tissues align to form the most efficient configuration for functioning. Vascular cells of arterial walls are constantly exposed to fluid shear stress and pressure-induced periodic strain component, both of which are induced by pulsatile flow. In the present study, the effect of cyclic strain on the cellular orientation response and morphological changes of bovine arterial wall cells such as endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblasts (FCs) was studied. Cells seeded onto transparent elastomeric films were subjected to periodic stretch-relaxation under various amplitudes ranging from 5 to 20% and at frequencies ranging from 15 to 120 RPM for up to 24 h. Time-lapse video-recorded images of stress-loaded cells were analyzed by a computer-aided morphometric system to quantitatively evaluate the cellular orientation responses and morphological changes. The stress-loaded cells tended to align perpendicularly to the direction of stretch with time, regardless of cellular species. More pronounced orientation was attained under operating conditions with higher amplitude and frequency of stretching. The response of SMCs and FCs advanced more rapidly than that of ECs. Meanwhile, little morphological change was observed, irrespective of stress-loading or nonloading. Understanding of mechanically induced orientation response provides a fundamental basis on tissue engineering and biomechanics.

Animals↗