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At least 217 records · Page 12Linked to original sources
PubMed2003

Global perception in small brains: topological pattern recognition in honey bees.

A series of experiments with honey bees demonstrate that their small brains nevertheless possess the ability for topological perception. Bees rapidly learned to discriminate patterns that are topologically different, and they generalized the learned cue to other novel patterns. By contrast, discrimination of topologically equivalent patterns was learned much more slowly and not as well. Thus, although the global nature of topological properties makes their computation difficult, topology may be a fundamental component of the vocabulary by which visual systems represent and characterize objects.

Animals↗
PubMed2002

Eye contact detection in humans from birth.

Making eye contact is the most powerful mode of establishing a communicative link between humans. During their first year of life, infants learn rapidly that the looking behaviors of others conveys significant information. Two experiments were carried out to demonstrate special sensitivity to direct eye contact from birth. The first experiment tested the ability of 2- to 5-day-old newborns to discriminate between direct and averted gaze. In the second experiment, we measured 4-month-old infants' brain electric activity to assess neural processing of faces when accompanied by direct (as opposed to averted) eye gaze. The results show that, from birth, human infants prefer to look at faces that engage them in mutual gaze and that, from an early age, healthy babies show enhanced neural processing of direct gaze. The exceptionally early sensitivity to mutual gaze demonstrated in these studies is arguably the major foundation for the later development of social skills.

Child Development↗
PubMed2004

Young and older adults exhibit proactive and reactive adaptations to repeated slip exposure.

BACKGROUND: A previous study found that, with repeated exposure to slipping during a sit-to-stand task, fall incidence decreased at a similar exponential rate in young and older adults. This study investigated the adaptations responsible for this decrease. METHODS: Slips were induced, using bilateral low-friction platforms, during a sit-to-stand in 60 young and 41 older healthy safety-harnessed adults. Participants underwent 5 slips, then a 6th slip (reslip) after 3-4 nonslipping trials. Between-trial adjustments in body center of mass state at seat-off were examined and correlated to the likelihoods of falling and stepping. Changes in reactive response between the first slip and reslip were investigated. RESULTS: With repeated slipping, both young and older adults adjusted to increase their center of mass anterior position and forward velocity at seat-off (p <.001), contributing to decreased fall incidence and changes in step incidence and direction (p <.001). These proactive adjustments predicted fall incidence well in later trials, but underpredicted fall incidence upon the first slip by 9%-21%, suggesting that reactive response deficiencies also initially contributed to falls by both age groups. Ten participants who initially fell without stepping adapted by stepping to recover upon the reslip. Thirty-six participants who stepped backward initially and upon the reslip altered their nonstepping limb reactive response to reduce hip vertical descent during the step (p <.001). CONCLUSIONS: Young and older adults rapidly learned to avoid falling through similar proactive and reactive adaptations that persisted in the short term. Both proactive and reactive adaptations should be targeted in interventions to reduce older adult fall incidence.

Accidental Falls↗
PubMed1998

Endoscopic harvest of the gracilis muscle flap.

Endoscopic technique is becoming increasing prevalent in plastic surgery and is being explored for use in tissue harvest for microneurovascular transplantation. To advance the art truly, endoscopic technique must provide similar success and complication rates, operative time, and ease of performance as the traditional "open" surgical harvest. We report the successful microvascular transplantation in 6 patients of gracilis muscles harvested with endoscopic guidance. Dissection of the primary pedicle was done through a small proximal incision, and subsequent dissection was accomplished with an endoscope through the primary incision and a small distal incision. This method provides excellent success of transfer and decreased morbidity compared with the open technique. Specifically, the resulting scar from the endoscopic technique is considerably smaller, with just a 5-cm proximal and a 1.5-cm distal scar. The technique is accomplished with standard endoscopic equipment and is learned rapidly. We believe the improved aesthetic outcome makes endoscopic gracilis harvest a preferred technique.

Adult↗
PubMed1991

Safety and efficacy of laparoscopic cholecystectomy. A prospective analysis of 100 initial patients.

Laparoscopic cholecystectomy quickly emerged as an alternative to open cholecystectomy. However its safety, efficacy, and morbidity have yet to be fully evaluated. During the first 6 months of 1990, we performed 100 consecutive laparoscopic cholecystectomies with no deaths and a morbidity rate of 8% (8 of 100 patients; 4 major, 4 minor). There were 81 women and 19 men, with a mean age of 46.1 years (range, 17 to 84 years). All patients had a preoperative history consistent with symptomatic biliary tract disease, and most had proved gallstones by sonography. This included four patients with acute cholecystitis. Mean operating time improved significantly from month 1 to month 6 (122 +/- 45.4 minutes versus 78.5 +/- 30 minutes, respectively), indicating a rapid learning curve. Mean hospital stay was 27.6 hours, reflecting a policy of overnight stay. Postoperative narcotic requirements were limited to oral or no medications in more than 70% of patients. A regular diet was tolerated by 83% of the patients by the morning following the procedure. Median time of return to full activity was 12.8 +/- 6.8 days after operation. In addition analysis of the hospital costs of these 100 cases demonstrates a modest cost advantage over standard open cholecystectomy (n = 58) (mean, $3620.25 +/- $1005.00 versus $4251.76 +/- $988.00). There was one minor bile duct injury requiring laparotomy and t-tube insertion, two postoperative bile collections, and one clinical diagnosis of a retained stone that passed spontaneously. Four patients required conversion to open cholecystectomy because of technical difficulties with the dissection. Although there is a significant learning curve, laparoscopic cholecystectomy is a safe and effective procedure that can be performed with minimal risk. Laparoscopic cholecystectomy should be performed by surgeons who are trained in biliary surgery and knowledgeable in biliary anatomy, and, as with all operations, it should be performed with meticulous attention to technique.

Adolescent↗
PubMed1997

Impaired spatial information processing in aged monkeys with preserved recognition memory.

Spatial information processing was examined in a non-human primate model of cognitive aging, using procedures formally similar to tasks designed for rats. The test apparatus was a large open field containing eight reward locations. Monkeys rapidly learned to visit each location once per trial, and probe manipulations confirmed that young animals navigated according to the distribution of cues surrounding the maze. In contrast, aged monkeys solved the task using a response sequencing strategy, independent of extramaze spatial information. Object recognition memory was normal in the aged group. The results reveal substantial correspondence in the cognitive effects of aging across rat and primate models, and they establish appropriate procedures for testing the long-standing proposal that the role of the hippocampus in normal spatial learning is similarly conserved.

Aging↗
PubMedDate not supplied

Real-time reporting drives the race toward zero.

LifeCare Hospitals of Pittsburgh is a 155-bed freestanding, Acute Long Term Care Hospital, one of 333 nationwide. Patients with complex care needs who are recovering from acute events, postsurgical interventions, and multiple comorbidities stay an average of 25 days. Like other hospitals, reducing medication errors is a focus of the quality improvement program. Provision of a safe environment is tantamount to achieving quality patient outcomes. Creative solutions to the problem of medication errors are needed. Healthcare executives need effective strategies to engage care providers in solving problems in the course of work and in a nonpunitive environment. Over the period of 1 year, medication errors reaching patients at LifeCare decreased by 50% through culture changes, rapid learning cycles, and strong support from the hospital's leaders.

Forms and Records Control↗
PubMed1997

Merger motorway. Giving staff the tools to reengineer.

Mergers and health care agencies' response to mergers dominate current conversations in this evolving managed care environment. Hospitals are rapidly learning to adjust to declining occupancy rates and deceased utilization of resources. A business model to guide mergers was adapted to assist staff with the people, structural, cultural and political issues of organizational change. Creating successful new work environments, moving from a "We-they" mentality to unity and decreasing use of resources are outcomes described in this article.

Adaptation, Psychological↗
PubMed1985

The use of hypnosis as a tool in plastic surgery.

Clinical hypnosis can be valuable tool for the plastic surgeon. Techniques can be rapidly learned at workshops that are held frequently at convenient locations throughout the country. Once misconceptions are dispelled, use of hypnosis is appropriate, safe, and effective.

Adult↗
PubMed2004

Neocortex size predicts deception rate in primates.

Human brain organization is built upon a more ancient adaptation, the large brain of simian primates: on average, monkeys and apes have brains twice as large as expected for mammals of their size, principally as a result of neocortical enlargement. Testing the adaptive benefit of this evolutionary specialization depends on finding an association between brain size and function in primates. However, most cognitive capacities have been assessed in only a restricted range of species under laboratory conditions. Deception of conspecifics in social circumstances is an exception, because a corpus of field data is available that encompasses all major lines of the primate radiation. We show that the use of deception within the primates is well predicted by the neocortical volume, when observer effort is controlled for; by contrast, neither the size of the rest of the brain nor the group size exert significant effects. These findings are consistent with the hypothesis that neocortical expansion has been driven by social challenges among the primates. Complex social manipulations such as deception are thought to be based upon rapid learning and extensive social knowledge; thus, learning in social contexts may be constrained by neocortical size.

Adaptation, Physiological↗
PubMed2002

The uses of colour vision: behavioural and physiological distinctiveness of colour stimuli.

Colour and greyscale (black and white) pictures look different to us, but it is not clear whether the difference in appearance is a consequence of the way our visual system uses colour signals or a by-product of our experience. In principle, colour images are qualitatively different from greyscale images because they make it possible to use different processing strategies. Colour signals provide important cues for segmenting the image into areas that represent different objects and for linking together areas that represent the same object. If this property of colour signals is exploited in visual processing we would expect colour stimuli to look different, as a class, from greyscale stimuli. We would also expect that adding colour signals to greyscale signals should change the way that those signals are processed. We have investigated these questions in behavioural and in physiological experiments. We find that male marmosets (all of which are dichromats) rapidly learn to distinguish between colour and greyscale copies of the same images. The discrimination transfers to new image pairs, to new colours and to image pairs in which the colour and greyscale images are spatially different. We find that, in a proportion of neurons recorded in the marmoset visual cortex, colour-shifts in opposite directions produce similar enhancements of the response to a luminance stimulus. We conclude that colour is, both behaviourally and physiologically, a distinctive property of images.

Animals↗
PubMed2005

Reconsolidation after remembering an odor-reward association requires NMDA receptors.

A rapidly learned odor discrimination task based on spontaneous foraging behavior of the rat was used to evaluate the role of N-methyl-D-aspartate (NMDA) receptors (NMDARs) in ongoing memory consolidation. Rats were trained in a single session to discriminate among three odors, one of which was associated with palatable food reward. Previous experiments showed that the NMDAR antagonist DL-APV induced amnesia for this task when injected immediately after training. In the present study, memory was reactivated 24 h after training by exposure to the rewarded odor within the experimental context after which rats received an intracerebroventricular injection of APV. Combined reactivation-drug treatment induced profound amnesia when tested 48 h later. Animals receiving drug alone, in absence of reactivation, showed perfect retention. It is concluded that NMDARs support a consolidation process taking place after memory reactivation.

Animals↗
PubMed2006

Impaired decision making following 49 h of sleep deprivation.

Sleep deprivation reduces regional cerebral metabolism within the prefrontal cortex, the brain region most responsible for higher-order cognitive processes, including judgment and decision making. Accordingly, we hypothesized that two nights of sleep loss would impair decision making quality and lead to increased risk-taking behavior on the Iowa Gambling Task (IGT), which mimics real-world decision making under conditions of uncertainty. Thirty-four healthy participants completed the IGT at rested baseline and again following 49.5 h of sleep deprivation. At baseline, volunteers performed in a manner similar to that seen in most samples of healthy normal individuals, rapidly learning to avoid high-risk decks and selecting more frequently from advantageous low-risk decks as the game progressed. After sleep loss, however, volunteers showed a strikingly different pattern of performance. Relative to rested baseline, sleep-deprived individuals tended to choose more frequently from risky decks as the game progressed, a pattern similar to, though less severe than, previously published reports of patients with lesions to the ventromedial prefrontal cortex. Although risky decision making was not related to participant age when tested at rested baseline, age was negatively correlated with advantageous decision making on the IGT, when tested following sleep deprivation (i.e. older subjects made more risky choices). These findings suggest that cognitive functions known to be mediated by the ventromedial prefrontal cortex, including decision making under conditions of uncertainty, may be particularly vulnerable to sleep loss and that this vulnerability may become more pronounced with increased age.

Adult↗
PubMed1997

Stable fly, Stomoxys calcitrans, mouthpart removal influences stress and anticipatory responses in mice.

Biting fly attack induces a variety of stress and anxiety related changes in the physiology and behaviour of the target animals. Significant reductions in pain, or more appropriately, nociceptive sensitivity (latency of a foot-lifting response to an aversive thermal stimulus), are evident in laboratory mice after a 1 h exposure to stable flies, Stomoxys calcitrans. The role of the various components of biting fly attack in the development of this stress-induced reduction in pain sensitivity (analgesia) is, however, unclear. This study demonstrates that fly-naive mice do not exhibit a stress-induced analgesia when exposed to stable flies whose biting mouthparts have been removed. In contrast, mice that have been previously exposed to intact stable flies exhibit significant analgesia when exposed to flies that are incapable of biting. However, the level of analgesia induced is lower than that elicited by exposure to intact stable flies. Exposure to nonbiting house flies, Musca domestica, has no effect on nociceptive sensitivity. It appears that the actual bite of the stable fly is necessary for the induction of analgesia and probably other stress and anxiety associated responses in fly naive mice. However, mice rapidly learn to recognize biting flies and exhibit significant, possibly anticipatory analgesic responses to the mere presence of biting flies.

Animals↗
PubMed2004

Development of a system for individual feeding of baboons maintained in an outdoor group social environment.

We developed a system that allows individual feeding of adult baboons, 8-15 years of age, maintained in an outdoor group social environment. The purpose of the system is to allow careful monitoring and control of individual diet. Baboons were housed in two group cages, 16 females and a single male in one and 12 females and a single male in the other. Baboons exited the group cage once daily and passed along a chute and over a scale into individual cages where they received their individual diets. Food intake was monitored during their 2-hour stay in the individual cages. Baboons rapidly learned to use this system. Food intake and weight were stable within 20 days. Food consumed decreased during the period of sexual receptivity. The maintenance of the group social environment allowed observations on the group's dominance structure and the relationship of dominance to food consumption. Speed of food access in the group cage was related to dominance. Dominance was not related to food consumed in individual cages. The system permits study of many variables related to behavior and food intake while still retaining critical social interactions.

Analysis of Variance↗
PubMed1975

Direction finding by hornets under gravitational and centrifugal forces.

The effect of centrifugal and gravitational forces whose resultant ranged between 26 degrees and 45 degrees on comb construction by hornet workers was assessed experimentally. Comb construction by hornets exposed to centrifugation at 1 to 2 days of age differed from that of hornets similarly exposed at 3 to 7 days of age. Juvenile hornets built their cells in the direction of the resultant force, whereas adults resisted the centrifugal force and tried to build in the direction of the gravitational force. Juveniles started their comb from the side walls, whereas adults started from the roof, as did nonspinning, control hornets. The findings suggest that hornets rapidly learn the gravitational force during the first days of life, and that they are aided by geometric cues of the breeding box to build in the direction of the force to which they had become habituated.

Age Factors↗
PubMed1988

Long-term synaptic potentiation.

Long-term synaptic potentiation (LTP) is a leading candidate for a synaptic mechanism of rapid learning in mammals. LTP is a persistent increase in synaptic efficacy that can be quickly induced. The biophysical process that controls one type of LTP is formally similar to a synaptic memory mechanism postulated decades ago by the psychologist Donald Hebb. A key aspect of the modification process involves the N-methyl-D-aspartate (NMDA) receptor-ionophore complex. This ionophore allows calcium influx only if the endogenous ligand glutamate binds to the NMDA receptor and if the voltage across the associated channel is also sufficiently depolarized to relieve a magnesium block. According to one popular hypothesis, the resulting increase in the intracellular calcium concentration activates protein kinases that enhance the postsynaptic conductance. Further biophysical and molecular understanding of the modification process should facilitate detailed explorations of the mnemonic functions of LTP.

Animals↗
PubMed1984

Anatomically distinct opiate receptor fields mediate reward and physical dependence.

Rats never before exposed to opioids rapidly learned to press a lever for microinjections of morphine into the ventral tegmental area. Challenge by a narcotic antagonist produced no signs of physical dependence. Dependence was not seen after long-term morphine infusions into the ventral tegmentum but was seen after similar infusions into the periventricular gray region. Thus a major rewarding property of morphine is independent of the drug's ability to produce physical dependence. These data challenge models of drug addiction that propose physical dependence as necessary for the rewarding effects of opioids.

Animals↗