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Stimulus equivalence

Nayan Chanauria, Vishal Bharmauria, Lyes Bachatene, Sarah Cattan, Jean Rouat, Stéphane Molotchnikoff
V1 is fundamentally grouped into columns that descend from layer II-III to layer V-VI. Neurons inherent to visual cortex are capable of adapting to changes in the incoming stimuli that drive the cortical plasticity. A principle feature called orientation selectivity can be altered by the presentation of non-optimal stimulus called 'adapter'. When triggered, LGN cells impinge upon layer IV and further relay the information to deeper layers via layer II-III. Using different adaptation protocols, neuronal plasticity can be investigated...
October 14, 2016: European Journal of Neuroscience
Erika van der Maten, Cynthia M de Bont, Ronald de Groot, Marien I de Jonge, Jeroen D Langereis, Michiel van der Flier
Bacterial pathogens not only stimulate innate immune receptors, but also activate the complement system. Crosstalk between complement C5a receptor (C5aR) and other innate immune receptors is known to enhance the proinflammatory cytokine response. An important determinant of the magnitude of complement activation is the activity of the alternative pathway, which serves as an amplification mechanism for complement activation. Both alternative pathway activity as well as plasma levels of factor H, a key inhibitor of the alternative pathway, show large variation within the human population...
October 6, 2016: Cytokine
Melissa Johnston, Catrona Anderson, Michael Colombo
We recorded neuronal activity from the nidopallium caudolaterale, the avian equivalent of mammalian prefrontal cortex, and the entopallium, the avian equivalent of the mammalian visual cortex, in four birds trained on a differential outcomes delayed matching-to-sample procedure in which one sample stimulus was followed by reward and the other was not. Despite similar incidence of reward-specific and reward-unspecific delay cell types across the two areas, overall entopallium delay activity occurred following both rewarded and non-rewarded stimuli, whereas nidopallium caudolaterale delay activity tended to occur following the rewarded stimulus but not the non-rewarded stimulus...
October 5, 2016: Behavioural Brain Research
Ke Zheng, Tian Han, Xingtao Zhou
BACKGROUND: To investigate accommodative response and accommodative lag changes after femtosecond laser small incision lenticule extraction (SMILE) for moderate to high myopia correction. METHODS: A total of 32 eyes of 32 patients with no strabismus who underwent SMILE were enrolled in this prospective clinical study. The accommodative response was obtained viewing monocularly with spherical equivalent refractive error corrected, using an open-field autorefractor at different stimulus levels (2...
October 4, 2016: BMC Ophthalmology
Alessandro Roncone, Matej Hoffmann, Ugo Pattacini, Luciano Fadiga, Giorgio Metta
This paper investigates a biologically motivated model of peripersonal space through its implementation on a humanoid robot. Guided by the present understanding of the neurophysiology of the fronto-parietal system, we developed a computational model inspired by the receptive fields of polymodal neurons identified, for example, in brain areas F4 and VIP. The experiments on the iCub humanoid robot show that the peripersonal space representation i) can be learned efficiently and in real-time via a simple interaction with the robot, ii) can lead to the generation of behaviors like avoidance and reaching, and iii) can contribute to the understanding the biological principle of motor equivalence...
2016: PloS One
W James Greville, Simon Dymond, Philip M Newton
PURPOSE: Esoteric jargon and technical language are potential barriers to the teaching of science and medicine. Effective teaching strategies which address these barriers are desirable. Here, we created and evaluated the effectiveness of stand-alone 'equivalence-based instruction' (EBI) learning resources wherein the teaching of a small number of direct relationships between stimuli (e.g., anatomical regions, their function, and pathology) results in the learning of higher numbers of untaught relationships...
2016: Journal of Educational Evaluation for Health Professions
Catherine E Myers, Janice Rego, Paul Haber, Kirsten Morley, Kevin D Beck, Lee Hogarth, Ahmed A Moustafa
This study adapts a widely-used acquired equivalence paradigm to investigate how opioid-addicted individuals learn from positive and negative feedback, and how they generalize this learning. The opioid-addicted group consisted of 33 participants with a history of heroin dependency currently in a methadone maintenance program; the control group consisted of 32 healthy participants without a history of drug addiction. All participants performed a novel variant of the acquired equivalence task, where they learned to map some stimuli to correct outcomes in order to obtain reward, and to map other stimuli to correct outcomes in order to avoid punishment; some stimuli were implicitly "equivalent" in the sense of being paired with the same outcome...
September 15, 2016: Behavioural Brain Research
John O'Neill, Ruth Anne Rehfeldt, Chris Ninness, Bridget E Muñoz, James Mellor
The purpose of the present study was to compare the effects of an online stimulus equivalence procedure to that of an assigned reading when learning Skinner's taxonomy of verbal behavior. Twenty-six graduate students participated via an online learning management system. One group was exposed to an online stimulus equivalence procedure (equivalence group) that was designed to teach relations among the names, antecedents, consequences, and examples of each elementary verbal operant. A comparison group (reading group) read a chapter from a popular textbook...
October 2015: Analysis of Verbal Behavior
Anna Fiedler, Sebastian Raeth, Fabian J Theis, Angelika Hausser, Jan Hasenauer
BACKGROUND: Ordinary differential equation (ODE) models are widely used to describe (bio-)chemical and biological processes. To enhance the predictive power of these models, their unknown parameters are estimated from experimental data. These experimental data are mostly collected in perturbation experiments, in which the processes are pushed out of steady state by applying a stimulus. The information that the initial condition is a steady state of the unperturbed process provides valuable information, as it restricts the dynamics of the process and thereby the parameters...
2016: BMC Systems Biology
Renato Roberto Vernucio, Paula Debert
Research about equivalence has commonly utilized human participants as experimental subjects. More recently, computational models have been capable of reproducing performances observed in experiments with humans. The computational model often utilized is called RELNET, and it simulates training and testing trials of conditional relations using the matching-to-sample procedure (MTS). The differentiation between sample stimulus and comparison stimuli, indispensable in MTS, implies operational difficulties for simulations...
2016: Psychological Record
Melissa Spilioti, Neil Vargesson, Peter Neri
All sensory devices, whether biological or artificial, carry appreciable amounts of intrinsic noise. When these internally generated perturbations are sufficiently large, the behaviour of the system is not solely driven by the external stimulus but also by its own spontaneous variability. Behavioural internal noise can be quantified, provided it is expressed in relative units of the noise source externally applied by the stimulus. In humans performing sensory tasks at near threshold performance, the size of internal noise is roughly equivalent to the size of the response fluctuations induced by the external noise source...
October 2016: Vision Research
J Poppenk, A R McIntosh, M Moscovitch
Stimulus repetition speeds behavioral responding (behavioral priming) and is accompanied by suppressed neural responses (repetition suppression; RS) that have been observed up to three days after initial exposure. While some proposals have suggested the two phenomena are linked, behavioral priming has been observed many years after initial exposure, whereas RS is widely considered a transitory phenomenon. This raises the question: what is the true upper limit of RS persistence? To answer this question, we scanned healthy, English-native adults with fMRI as they viewed novel (Asian) proverbs, recently repeated (Asian) proverbs, and previously known (English) proverbs that were matched on various dimensions...
September 2016: Neuropsychologia
Dómhnall J Jennings, Charlotte Bonardi
An experiment with rats compared the ability of fixed and variable duration cues to produce blocking. Rats in Group B (Blocking) were trained that both fixed- (F) and variable- (V) duration cues would be followed by food delivery. In a subsequent training stage F and V continued to be reinforced, but F was accompanied by X, and V by Y. In the test phase responding to X and Y was examined. Control Group O (Overshadowing) received identical treatment, except that F and V were nonreinforced in the first training stage...
July 25, 2016: Quarterly Journal of Experimental Psychology: QJEP
Jeroen C P Simons, Eric Pierce, Daniel Diaz-Gil, Sanjana A Malviya, Matthew J Meyer, Fanny P Timm, Janne B Stokholm, Carl E Rosow, Robert M Kacmarek, Matthias Eikermann
BACKGROUND: Volatile anesthetics and propofol impair upper airway stability and possibly respiratory upper airway dilator muscle activity. The magnitudes of these effects have not been compared at equivalent anesthetic doses. We hypothesized that upper airway closing pressure is less negative and genioglossus activity is lower during deep compared with shallow anesthesia. METHODS: In a randomized controlled crossover study of 12 volunteers, anesthesia with propofol or sevoflurane was titrated using a pain stimulus to identify the threshold for suppression of motor response to electrical stimulation...
September 2016: Anesthesiology
Dióghenes Pimenta, François Tonneau
Human subjects were exposed to AB, AC stimulus pairs and then to matching-to-sample tests of stimulus equivalence (B-A, C-A, B-C, C-B) or to a task in which stimulus compounds (BA, CA, BC, CB) were rated for attractiveness. Matching-to-sample tests revealed emergent B-A, C-A, B-C, and C-B choices, replicating previous results in the literature. The mean proportion of correct, emergent choices increased as a function of exposure to the AB, AC pairs. On the rating task, the liking scores of all stimulus compounds also increased as a function of exposure to the AB, AC pairs...
September 2016: Behavioural Processes
Laura Pieper, Rudolf Staufenbiel, Jana Christ, Lothar Panicke, Uwe Müller, Gudrun A Brockmann
Selection for improved health and welfare in farm animals is of increasing interest worldwide. Peripartum energy balance is a key factor for pathogenesis of diseases in dairy cows. The intravenous glucose tolerance test (ivGTT) can be used to study the metabolic response to a glucose stimulus. The aim of this study was to estimate heritability of ivGTT traits in German Holstein bulls. A total of 541 Holstein bulls aged 7 to 17 mo from 2 breeding stations were subjected to the ivGTT. Serum glucose concentrations were measured at 0, 7, 14, 21, 28, 35, 42, 49, 56, and 63 min relative to glucose infusion...
September 2016: Journal of Dairy Science
Agnes Yiu Jeung Choi, Lisa Nivison-Smith, Sieu K Khuu, Michael Kalloniatis
PURPOSE: Recent studies propose that the use of target stimuli within or close to complete spatial summation reveal larger threshold elevation in ocular disease. The Humphrey Visual Field Analyzer (HFA) is used to assess visual function yet the spatial summation characteristics are unexplored for the central macular region. We therefore wanted to establish the relationship between contrast sensitivity and stimulus size (spatial summation) within the central 20° visual field using the high sampling density of the 10-2 test grid...
2016: PloS One
Mark E Bouton, Sydney Trask, Rodrigo Carranza-Jasso
Five experiments tested implications of the idea that instrumental (operant) extinction involves learning to inhibit the learned response. All experiments used a discriminated operant procedure in which rats were reinforced for lever pressing or chain pulling in the presence of a discriminative stimulus (S), but not in its absence. In Experiment 1, extinction of the response (R) in the presence of S weakened responding in S, but equivalent nonreinforced exposure to S (without the opportunity to make R) did not...
July 2016: Journal of Experimental Psychology. Animal Learning and Cognition
David B Green, Jocelyn Ohlemacher, Merri J Rosen
Perceptual learning (training-induced performance improvement) can be elicited by task-irrelevant stimulus exposure in humans. In contrast, task-irrelevant stimulus exposure in animals typically disrupts perception in juveniles while causing little to no effect in adults. This may be due to the extent of exposure, which is brief in humans while chronic in animals. Here we assessed the effects of short bouts of passive stimulus exposure on learning during development in gerbils, compared with non-passive stimulus exposure (i...
2016: Frontiers in Neuroscience
Nanna de Rezende Strander, Lars Ståhle, Per T Hansson
The primary objective of this pilot study was to assess if the magnitude estimation of suprathreshold brushing, warmth (40 °C), and cold (25 °C) stimuli of the skin over the dorsum of the hand and the dorsum of the foot are comparable to the perceived intensity for the same stimuli applied to the skin over any of the following areas: forehead, m. trapezius, m. deltoideus, thoracic back, and lumbar back, respectively. Thirty-two subjects aged 18-64 years were included. Participants were examined by two physicians on two different occasions, 1-58 days apart...
June 2016: Somatosensory & Motor Research
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