Concept: The First Session
Reasons for performing the study: The ability of horses to habituate to novel objects influences safety in the horse-human relationship. However, the effectiveness of different habituation techniques has not been investigated in detail. Objectives: 1) To investigate whether horses show increased stress responses when negatively reinforced to approach novel objects, compared with horses allowed to voluntarily explore the objects and 2) whether a negatively reinforced approach facilitates object habituation. Methods: Twenty-two 2-3-year-old Danish Warmblood geldings were included. Half of the horses (NR group) were negatively reinforced by a familiar human handler to approach a collection of novel objects in a test arena. The other half were individually released in the arena and were free to explore the objects (VOL group). On the next day, the horses were exposed to the objects again without a human handler, to investigate the rate of habituation. Behavioural and heart rate responses were recorded. Results: All VOL horses initially avoided the unknown objects, whereas the handler was able to get all NR horses to approach and stand next to the objects within the first 2 min session. The NR horses had a significantly longer duration of alertness and a higher max heart rate in the first session. On the next day, however, NR horses spent significantly less time investigating the objects and had a shorter latency to approach a feed container, placed next to the objects, indicating increased habituation. Conclusion: A negatively reinforced approach to novel objects increases stress responses during the initial exposure but facilitates habituation in young horses. Potential relevance: Although a negatively reinforced approach appears beneficial for habituation, the procedure should be carefully managed due to increased stress responses in the horse, which may constitute a safety risk. Further experiments should aim to investigate differences in stimulus intensity.
- The journal of pain : official journal of the American Pain Society
- Published about 6 years ago
The purpose of this study was to examine opioid and endocannabinoid mechanisms of exercise-induced hypoalgesia (EIH). Fifty-eight men and women (mean age = 21 yrs) completed three sessions. During the first session, participants were familiarized with the temporal summation of heat pain and pressure pain protocols. In the exercise sessions, following double-blind administration of either an opioid antagonist (50 mg naltrexone) or placebo, participants rated the intensity of heat pulses and indicated their pressure pain thresholds (PPT) and ratings (PPR) before and after 3 minutes of submaximal isometric exercise. Blood was drawn before and after exercise. Results indicated circulating concentrations of two endocannabinoids, N-arachidonylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG) as well as related lipids oleoylethanolamide (OEA), palmitoylethanolamide (PEA), N-docsahexaenoylethanolamine (DHEA), and 2-oleoylglycerol (2-OG) increased significantly (p < 0.05) following exercise. PPT increased significantly (p < 0.05) while PPR decreased significantly (p < 0.05) following exercise. Also, temporal summation ratings were significantly lower (p < 0.05) following exercise. These changes in pain responses did not differ between placebo or naltrexone conditions (p > 0.05). A significant association was found between EIH and DHEA. These results suggest involvement of a non-opioid mechanism in EIH following isometric exercise.
- Journal of strength and conditioning research / National Strength & Conditioning Association
- Published about 8 years ago
Blatnik, JA, Skinner, JW, and McBride, JM. Effect of supportive equipment on force, velocity, and power in the squat. J Strength Cond Res 26(12): 3204-3208, 2012-The purpose of this investigation was to examine various kinetic and kinematic variables associated with squats without and with the use of a squat suit (SS). No previous investigation has examined the effect of an SS on squat performance. Participants were 8 elite or professional level male powerlifters (height = 178.59 ± 3.5 cm; body mass = 106.8 ± 30.4 kg; age = 25 ± 2.2 years; mean 1 repetition maximum [1RM] =197.7 ± 53 kg). Subjects participated in 3 testing sessions, with the first session involving a 1RM squat without a squat suit (NSS). Sessions 2 and 3 involved a testing session completing 2 trials in the squat at 3 intensities (80, 90, and 100% of 1RM) either without (NSS) or with an SS. The session and order of the intensities were all randomized. Force-time, velocity-time, and power-time graphs were calculated from data from a force plate and 2 linear position transducers attached to the barbell. Peak eccentric force was significantly higher during SS at 100% of 1RM (NSS-100 = 3196.2 ± 470.6, SS-100 = 3369.7 ± 589.9 N). Peak concentric velocity was significantly higher during SS in comparison to NSS at all intensities. Peak concentric power was significantly higher during SS at 80% of 1RM (NSS-80 = 1566.5 ± 388.4 W, SS-80 = 1770.4 ± 483.2 W) and 90% of 1RM (NSS-90 = 1493.1 ± 296.2 W, SS-90 = 1723.8 ± 449.5 W). The current investigation has demonstrated significantly different kinetic and kinematic characteristics between squats without (NSS) and with an SS, which could ultimately aid in enhancing squat performance.
Onyx embolization is a treatment for brain arteriovenous malformations (AVMs). However, multistage embolization usually involves the presence of radiodense Onyx cast from the previous sessions, which may influence the fluoroscopic radiation dose. We compared the fluoroscopic dose between the initial and final embolization sessions.
The definition of sepsis was updated to sepsis-3 in February 2016. Currently, direct hemoperfusion therapy using the polymyxin B-immobilized fiber cartridge (PMX-DHP) is widely performed to treat sepsis and septic shock. However, the prognostic factors of PMX-DHPs in patients with sepsis using the new definition are unclear. We retrospectively assessed prognostic factors in patients who had received PMX-DHP therapy for sepsis and septic shock.
Hyaluronic acid (HA) is used extensively in aesthetic medicine thanks to its documented role in skin rejuvenation. The specific applications of HA-based products are not always fully acknowledged due to a lack of consistent recommendations. In this paper, the authors have summarized available published data on the range of applications of non-animal stabilized hyaluronic acid (NASHA®) gel skin boosters (NSBs) in several anatomical areas and types of patient, as well as their own recommendations. Overall, the panel agreed that a standard initial protocol treatment of up to 3 sessions, followed by a maintenance schedule, would allow patients to improve and then preserve skin quality over time. Indeed, distinct effects are evident after the first session, but a progressive enhancement of skin texture is detectable for up to 12 months after repeat treatment at 4 to 6 month intervals. Moreover, the authors agreed that the NASHA gel, reaching the dermis, is able to reestablish a greater degree of hydration and stimulate collagen that, in turn, restores the volume and density of the skin. Thus, a strong consensus was reached that NSB procedures are minimally invasive, safe, and effective, and designed to improve skin texture and maintain skin quality.
J Drugs Dermatol. 2018;17(1):83-88..
Substantial transfer of perceptual skill learning can be achieved across large distances in the visual field by a brief pre-test, training-plus-exposure, or a double-training paradigm (Current Biology 18 (2008) 1922-1926; Vision Research 50 (2010) 368-374; The Journal of Neuroscience 30 (2010) 12323-12328). Additionally, subliminal exposure has been shown to be beneficial for subsequent perceptual learning. Here, we tested the generalization of orientation discrimination learning from a fully trained location towards four other test locations, either in the same or opposite hemifield as the training location, which each were subjected to a different type of pre-conditioning. In one test location, there was brief pre-testing in the first session. Two other locations were stimulated by masked stimuli similar or identical to concurrently presented stimuli in the training location. In the fourth test location, no stimuli were presented during training. Generalization of training to test locations was measured in the session immediately following the completion of training in the training location. Moreover, to test the robustness of transfer, training was continued in all four test locations. The experiment as a whole consisted of 15 sessions of orientation discrimination learning at the training location, followed by 15 sessions of training in the test locations. We found only limited generalization from the trained to the test locations. Performance in pre-tested and stimulated test locations showed a small advantage compared to the unstimulated test location. However, this advantage disappeared within a few sessions of further training in the test locations.
Transcranial direct current stimulation (tDCS) is a noninvasive tool to facilitate brain plasticity and enhance language abilities. Our study aims to search for a potential beneficial influence of tDCS on a cognitive linguistic task of naming which found to decline during aging. A group of fifteen healthy old adults [Formula: see text] were tested in naming 50 pictures of objects. Each subject participated in two sessions spanning on a one week period. One session included active tDCS stimulation and the other sham-placebo like stimulation. Subjects were blinded to stimulation type. During the active stimulation a bilateral protocol of anodal tDCS to the left Inferior Frontal Gyrus (IFG) combined with cathodal tDCS to the right IFG was delivered. Half of participants received active stimulation at the first session and sham at the second and half received the stimulations at the opposite order. Naming reaction time was measured at baseline, after active tDCS stimulation and after sham. 10 min of bilateral tDCS stimulation which was given after sham (training) was found to reduce naming reaction time among healthy adult subjects. These findings support the cooperative model (Weems and Reggia in Brain Lang 89:554-568, 2004) and point on strong interhemispheric connections during naming processing. It is also demonstrate the advantage of training to intensify the therapeutic effect of tDCS. Our results pinpoint on a potential tool to facilitate naming among aging people.
- Neuropsychology, development, and cognition. Section B, Aging, neuropsychology and cognition
- Published almost 4 years ago
Age-related memory change has been a topic of much investigation in recent years, including spacing benefits and reliance on contextual cues. We manipulated the spacing schedule and the context of learning and observed the effects on long-term recall ability in healthy older and younger adults. After learning Swahili-English word pairs, half practiced immediately (massed) and half practiced 24 h later (spaced) either in the same room or a different room (context) from the initial session. A final recall test 10 days after the practice session occurred in the same room as the first session. Participants in the spaced condition remembered more than those in the massed condition 10 days later. Younger adults remembered more word pairs than older adult participants. Context change eliminated the spacing benefit for both age groups.
Electromyography-based human-computer interface development is an active field of research. However, knowledge on the effects of muscle fatigue for specific devices is limited. We have developed a novel myoelectric human-computer interface in which subjects continuously navigate a cursor to targets by manipulating a single surface electromyography (sEMG) signal. Two-dimensional control is achieved through simultaneous adjustments of power in two frequency bands through a series of dynamic low-level muscle contractions. Here, we investigate the potential effects of muscle fatigue during the use of our interface. In the first session, eight subjects completed 300 cursor-to-target trials without breaks; four using a wrist muscle and four using a head muscle. The wrist subjects returned for a second session in which a static fatiguing exercise took place at regular intervals in-between cursor-to-target trials. In the first session we observed no declines in performance as a function of use, even after the long period of use. In the second session, we observed clear changes in cursor trajectories, paired with a target-specific decrease in hit rates.