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Stimulus equivalence

Emily Lauren Graczyk, Benoit Delhaye, Matthew A Schiefer, Sliman J Bensmaia, Dustin J Tyler
Sensory systems adapt their sensitivity to ambient stimulation levels to improve their responsiveness to changes in stimulation. The sense of touch is also subject to adaptation, as evidenced by the desensitization produced by prolonged vibratory stimulation of the skin. Electrical stimulation of nerves elicits tactile sensations that can convey feedback for bionic limbs. In this study, we investigate whether artificial touch is also subject to adaptation, despite the fact that the peripheral mechanotransducers are bypassed...
March 19, 2018: Journal of Neural Engineering
William J McIlvane, Joanne B Kledaras, Christophe J Gerard, Lorin Wilde, David Smelson
A few noteworthy exceptions notwithstanding, quantitative analyses of relational learning are most often simple descriptive measures of study outcomes. For example, studies of stimulus equivalence have made much progress using measures such as percentage consistent with equivalence relations, discrimination ratio, and response latency. Although procedures may have ad hoc variations, they remain fairly similar across studies. Comparison studies of training variables that lead to different outcomes are few. Yet to be developed are tools designed specifically for dynamic and/or parametric analyses of relational learning processes...
March 12, 2018: Behavioural Processes
Mahan Azadpour, Colette M McKay, Mario A Svirsky
Stimulation pulse rate affects current amplitude discrimination by cochlear implant (CI) users, indicated by the evidence that the JND (just noticeable difference) in current amplitude delivered by a CI electrode becomes larger at higher pulse rates. However, it is not clearly understood whether pulse rate would affect discrimination of speech intensities presented acoustically to CI processors, or what the size of this effect might be. Intensity discrimination depends on two factors: the growth of loudness with increasing sound intensity and the loudness JND (or the just noticeable loudness increment)...
March 12, 2018: Journal of the Association for Research in Otolaryngology: JARO
Nino Andricevic, Mirko Junge, Jonas Krampe
OBJECTIVE: Construction of Injury risk functions (IRF) for front row occupants in oblique frontal crashes and a comparison to IRF of non-oblique frontal crashes from the same dataset. METHOD: Crashes of modern vehicles from the GIDAS (German In-depth Accident Study) were used as the basis for the construction of a logistic injury risk model. Static deformation, measured via displaced voxels on the post-crash vehicles, was used to calculate the energy dissipated in the crash...
March 9, 2018: Traffic Injury Prevention
Kyoung-Ho Ryu, Keulame Song, Tae-Young Lim, Won-Jun Choi, Yun-Hong Kim, Hyun-Soo Kim
BACKGROUND: Minimum alveolar concentration (MAC) has traditionally been used to compare the potency of volatile anesthetics. However, as it reflects the spinal mechanism of immobility rather than the cerebral mechanism of analgesia and hypnosis, it is doubtful that equi-MAC connotes equivalent analgesic or hypnotic potency. The level of analgesia and hypnosis can be assessed using surgical pleth index and bispectral index (BIS) values, respectively. This study was designed to compare the surgical pleth index and BIS values produced by equi-MAC of desflurane and sevoflurane in patients undergoing single-agent volatile anesthesia...
March 6, 2018: Anesthesiology
Elberto A Plazas, Carlos-Wilcen Villamil
This study presents three experiments that aimed to show the formation of stimulus equivalence relations among stimuli that had been previously related only by exclusion. In Experiment 1, participants were trained on baseline conditional discriminations to establish two 3-member equivalence classes. Then, they were exposed to exclusion trials, without feedback, in which undefined stimuli had to be matched by rejecting the defined baseline stimuli. Finally, participants responded to test trials evaluating the emergence of symmetry and transitivity among the undefined stimuli from the exclusion trials...
March 6, 2018: Journal of the Experimental Analysis of Behavior
Anthony A Wright, Debbie M Kelly, Jeffrey S Katz
This article describes an approach for training a variety of species to learn the abstract concept of same/different, which in turn forms the basis for testing proactive interference and list memory. The stimulus set for concept-learning training was progressively doubled from 8, 16, 32, 64, 128 . . . to 1,024 different pictures with novel-stimulus transfer following learning. All species fully learned the same/different abstract concept: capuchin and rhesus monkeys learned more readily than pigeons; nutcrackers and magpies were at least equivalent to monkeys and transferred somewhat better following initial training sets...
February 28, 2018: Learning & Behavior
Xin Chen, Jinsong Gao, Bonan Kang
We introduce a structurally reconfigurable metasurface which is made of shape memory alloys (SMA). It could change the morphology of the unit cells repeatedly as we expect in response to a thermal stimulus and realize a tuning range from 13.3GHz to 17.2GHz for both polarizations simultaneously. Equivalent circuit models describe the operational principle and design methodology, the physical mechanism is interpreted with the variation of surface current distribution on the structure. The experimental results coincide with the numerical simulations, making the all-metal metasurface an attractive choice for manipulating the electromagnetic wave in a wide range of spectrums with the merits of higher controllability for dynamic behavior and greater freedom for design and manufacturing...
February 19, 2018: Optics Express
Mellissa Harden, Alex Wolf, Mark Russell, Kirsty M Hicks, Duncan French, Glyn Howatson
High intensity eccentric exercise is a potent stimulus for neuromuscular adaptation. A greater understanding of the mechanical stimuli afforded by this exercise will aid the prescription of future eccentric training regimes. This study sought to investigate the mechanical characteristics of supramaximally loaded eccentric exercise when using a custom-built leg press machine. Using a within subject, repeated measures design, 15 strength trained subjects (age 31 ± 7 years; height 180.0 ± 6.8 cm; body mass 81...
February 20, 2018: Journal of Strength and Conditioning Research
Jordana S Wynn, Rosanna K Olsen, Malcolm A Binns, Bradley R Buchsbaum, Jennifer D Ryan
Research using eye movement monitoring suggests that recapitulating the pattern of eye movements made during stimulus encoding at subsequent retrieval supports memory by reinstating the spatial layout of the encoded stimulus. In the present study, the authors investigated whether recapitulation of encoding fixations during a poststudy, stimulus-free delay period-an effect that has been previously linked to memory maintenance in younger adults-can support mnemonic performance in older adults. Older adults showed greater delay-period fixation reinstatement than younger adults, and this reinstatement supported age-equivalent performance on a subsequent visuospatial-memory-based change detection task, whereas in younger adults, the performance-enhancing effects of fixation reinstatement increased with task difficulty...
February 22, 2018: Journal of Experimental Psychology. Human Perception and Performance
Amanda I Rodriguez, Megan L A Thomas, Denis Fitzpatrick, Kristen L Janky
OBJECTIVES: Vestibular evoked myogenic potential (VEMP) testing is increasingly utilized in pediatric vestibular evaluations due to its diagnostic capability to identify otolith dysfunction and feasibility of testing. However, there is evidence demonstrating that the high-intensity stimulation level required to elicit a reliable VEMP response causes acoustic trauma in adults. Despite utility of VEMP testing in children, similar findings are unknown. It is hypothesized that increased sound exposure may exist in children because differences in ear-canal volume (ECV) compared with adults, and the effect of stimulus parameters (e...
March 2018: Ear and Hearing
Scott F Lempka, Bryan Howell, Kabilar Gunalan, Andre G Machado, Cameron C McIntyre
OBJECTIVE: To determine the circuit elements required to theoretically describe the stimulus waveforms generated by an implantable pulse generator (IPG) during clinical deep brain stimulation (DBS). METHODS: We experimentally interrogated the Medtronic Activa PC DBS IPG and defined an equivalent circuit model that accurately captured the output of the IPG. We then compared the detailed circuit model of the clinical stimulus waveforms to simplified representations commonly used in computational models of DBS...
January 31, 2018: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Vanessa Ayres-Pereira, Daniela S Canovas, André A B Varella, Deisy G de Souza
Generalized equivalence classes are stimulus classes that consist of equivalent stimuli and other physically similar class-member stimuli. The present study evaluated whether preschool children would form equivalence classes among photos of abstract objects (2D) and show equivalence generalization to the corresponding objects (3D), printed photos (2D stimuli), and to black-and-white drawn pictures (2D stimuli). Six typically developing children were taught arbitrary relations to establish three 3-member equivalence classes with 2D stimuli presented on a computer screen...
February 9, 2018: Journal of the Experimental Analysis of Behavior
Margaret C Wardle, Paula Lopez-Gamundi, Shelly B Flagel
Clinical and preclinical findings suggest that individuals with abnormal responses to reward cues (stimuli associated with reward) may be at risk for maladaptive behaviors including obesity, addiction and depression. Our objective was to develop a new paradigm for producing appetitive conditioning using primary (food) rewards in humans, and investigate the equivalency of several outcomes previously used to measure appetitive responses to conditioned cues. We used an individualized food reward, and multimodal subjective, psychophysiological and behavioral measures of appetitive responses to a conditioned stimulus (CS) that predicted delivery of that food...
February 2, 2018: Physiology & Behavior
Kristina Küper, Hubert D Zimmer
It is still unclear which role the right hemisphere (RH) preference for perceptually specific and the left hemisphere (LH) bias towards abstract memory representations play at the level of episodic memory retrieval. When stimulus characteristics hampered the retrieval of abstract memory representations, these hemispheric asymmetries have previously only modulated event-related potential (ERP) correlates of recollection (late positive complex, LPC), but not of familiarity (FN400). In the present experiment, we used stimuli which facilitated the retrieval of abstract memory representations...
January 19, 2018: Brain and Cognition
Louise O'Hare, Federica Menchinelli, Simon J Durrant
Migraine groups show differences in motion perception compared with controls, when tested in between migraine attacks (interictally). This is thought to be due to an increased susceptibility to stimulus degradation (multiplicative internal noise). Fluctuations in alpha-band oscillations are thought to regulate visual perception, and so differences could provide a mechanism for the increased multiplicative noise seen in migraine. The aim of this article was to characterise resting-state alpha-band oscillations (between 8 and 12 Hz) in the visual areas of the brain in migraine and control groups...
January 1, 2018: Perception
Chiara Milanese, Valentina Cavedon, Marco Sandri, Enrico Tam, Francesco Piscitelli, Federico Boschi, Carlo Zancanaro
The ability of whole body vibration (WBV) to increase energy expenditure (EE) has been investigated to some extent in the past using short-term single exercises or sets of single exercises. However, the current practice in WBV training for fitness is based on the execution of multiple exercises during a WBV training session for a period of at least 20 min; nevertheless, very limited and inconsistent data are available on EE during long term WBV training session. This crossover study was designed to demonstrate, in an adequately powered sample of participants, the ability of WBV to increase the metabolic cost of exercise vs...
2018: PloS One
Bahadir Kasap, A John Van Opstal
In dynamic visual or auditory gaze double-steps, a brief target flash or sound burst is presented in midflight of an intervening eye-head gaze shift. Behavioral experiments in humans and monkeys have indicated that the subsequent eye- and head movements to the target are goal-directed, regardless stimulus timing, first gaze-shift characteristics, and initial conditions. This remarkable behavior requires that the gaze-control system (i) has continuous access to accurate signals about eye-in-head position, and ongoing eye-head movements, (ii) that it accounts for different internal signal delays, and (iii) that it is able to update the retinal (TE) and head-centric (TH) target coordinates into appropriate eye-centered and head-centered motor commands on millisecond time scales...
January 31, 2018: Journal of Neurophysiology
Kazuyoshi Nakanishi, Tomoshi Watanabe, Toru Sunagawa, Hiroshi Kurumadani, Hanan Abd El-Rahman, Mitsuo Ochi, Nobuo Adachi
The aim of this study was to investigate the effect of finger-tip touch on the somatosensory cortex under mirror imaging conditions. Magnetoencephalographic recordings of somatosensory-evoked field responses to mechanical tactile stimulation of the index finger in both hands were obtained for the right-handed healthy participants as part of the following mirror or nonmirror tasks. Both hands were screened and mechanical stimuli were delivered to the right index finger pulp. A mirror was placed in front of the patient with the right hand facing the reflective surface, as if it were the left side (mirror task)...
January 4, 2018: Neuroreport
Adam H Doughty, Casey M Irwin
The experimental analysis of derived stimulus relations is a critical research area. A training-then-testing preparation nearly always is used to study derived relations. In the training phase, participants learn the relevant baseline discriminations via differential consequences (e.g., AB and AC relations). In the testing phase, they are presented with probe trials in the absence of differential consequences (e.g., BA and CA symmetry trials and BC and CB equivalence trials). High accuracy levels sometimes are observed from the start of testing such that it is unclear whether the participants learned these relations before testing...
December 28, 2017: Behavioural Processes
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