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Stimulus equivalence

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https://www.readbyqxmd.com/read/28185226/memory-and-learning-for-visual-signals-in-time-and-space
#1
Sujala Maharjan, Jason M Gold, Robert Sekuler
Vision is often characterized as a spatial sense, but what does that characterization imply about the relative ease of processing visual information distributed over time rather than over space? Three experiments addressed this question, using stimuli comprising random luminances. For some stimuli, individual items were presented sequentially, at 8 Hz; for other stimuli, individual items were presented simultaneously, as horizontal spatial arrays. For temporal sequences, subjects judged whether each of the last four luminances matched the corresponding luminance in the first four; for spatial arrays, they judged whether each of the right-hand four luminances matched the corresponding left-hand luminance...
February 9, 2017: Attention, Perception & Psychophysics
https://www.readbyqxmd.com/read/28166900/effects-of-auditory-and-tactile-warning-on-response-to-visual-hazards-under-a-noisy-environment
#2
Atsuo Murata, Takashi Kuroda, Waldemar Karwowski
A warning signal presented via a visual or an auditory cue might interfere with auditory or visual information inside and outside a vehicle. On the other hand, such interference would be certainly reduced if a tactile cue is used. Therefore, it is expected that tactile cues would be promising as warning signals, especially in a noisy environment. In order to determine the most suitable modality of cue (warning) to a visual hazard in noisy environments, auditory and tactile cues were examined in this study. The condition of stimulus onset asynchrony (SOA) was set to 0ms, 500ms, and 1000ms...
April 2017: Applied Ergonomics
https://www.readbyqxmd.com/read/28147574/calibration-of-brief-stimuli-for-the-recording-of-evoked-responses-from-the-human-auditory-pathway
#3
Claus Elberling, Lau Crone Esmann
The relationship between the calibration RETSPL-values (reference equivalent threshold sound pressure level) in dB p-p.e.SPL and the corresponding sound pressure levels in dB SPL for brief stimuli is formulated mathematically. The formula is applied on ten brief stimuli consisting of a click, four tone-bursts, a chirp, and four octave-band chirps presented at a stimulus rate of 20 stimuli per second, and using the average acoustical parameter-values from a sample of 20 ER-3A insert earphones in the occluded-ear simulator...
January 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28135347/comparing-sensitivity-estimates-from-mlds-and-forced-choice-methods-in-a-slant-from-texture-experiment
#4
Guillermo Aguilar, Felix A Wichmann, Marianne Maertens
Maximum likelihood difference scaling (MLDS) is a method for the estimation of perceptual scales based on the judgment of differences in stimulus appearance (Maloney & Yang, 2003). MLDS has recently also been used to estimate near-threshold discrimination performance (Devinck & Knoblauch, 2012). Using MLDS as a psychophysical method for sensitivity estimation is potentially appealing, because MLDS has been reported to need less data than forced-choice procedures, and particularly naive observers report to prefer suprathreshold comparisons to JND-style threshold tasks...
January 1, 2017: Journal of Vision
https://www.readbyqxmd.com/read/28135213/brain-activity-for-tactile-allodynia-a-longitudinal-awake-rat-functional-magnetic-resonance-imaging-study-tracking-emergence-of-neuropathic-pain
#5
Pei-Ching Chang, Maria Virginia Centeno, Daniel Procissi, Alex Baria, A Vania Apkarian
Tactile allodynia, a condition in which innocuous mechanical stimuli are perceived as painful, is a common feature of chronic pain. However, how the brain reorganizes in relation to the emergence of tactile allodynia is still largely unknown. This may stem from the fact that experiments in humans are cross-sectional in nature, whereas animal brain imaging studies typically require anaesthesia rendering the brain incapable of consciously sensing or responding to pain. In this longitudinal functional magnetic resonance imaging study in awake rats, we tracked brain activity with the development of tactile allodynia...
March 2017: Pain
https://www.readbyqxmd.com/read/28114492/factorizing-the-motion-sensitivity-function-into-equivalent-input-noise-and-calculation-efficiency
#6
Rémy Allard, Angelo Arleo
The photopic motion sensitivity function of the energy-based motion system is band-pass peaking around 8 Hz. Using an external noise paradigm to factorize the sensitivity into equivalent input noise and calculation efficiency, the present study investigated if the variation in photopic motion sensitivity as a function of the temporal frequency is due to a variation of equivalent input noise (e.g., early temporal filtering) or calculation efficiency (ability to select and integrate motion). For various temporal frequencies, contrast thresholds for a direction discrimination task were measured in presence and absence of noise...
January 1, 2017: Journal of Vision
https://www.readbyqxmd.com/read/28114353/computational-account-of-spontaneous-activity-as-a-signature-of-predictive-coding
#7
Veronika Koren, Sophie Denève
Spontaneous activity is commonly observed in a variety of cortical states. Experimental evidence suggested that neural assemblies undergo slow oscillations with Up ad Down states even when the network is isolated from the rest of the brain. Here we show that these spontaneous events can be generated by the recurrent connections within the network and understood as signatures of neural circuits that are correcting their internal representation. A noiseless spiking neural network can represent its input signals most accurately when excitatory and inhibitory currents are as strong and as tightly balanced as possible...
January 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/28076814/gsmtx4-mechanism-of-inhibiting-mechanosensitive-ion-channels
#8
Radhakrishnan Gnanasambandam, Chiranjib Ghatak, Anthony Yasmann, Kazuhisa Nishizawa, Frederick Sachs, Alexey S Ladokhin, Sergei I Sukharev, Thomas M Suchyna
GsMTx4 is a spider venom peptide that inhibits cationic mechanosensitive channels (MSCs). It has six lysine residues that have been proposed to affect membrane binding. We synthesized six analogs with single lysine-to-glutamate substitutions and tested them against Piezo1 channels in outside-out patches and independently measured lipid binding. Four analogs had ∼20% lower efficacy than the wild-type (WT) peptide. The equilibrium constants calculated from the rates of inhibition and washout did not correlate with the changes in inhibition...
January 10, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28062154/phototransduction-early-steps-model-based-on-beer-lambert-optical-law
#9
Ezequiel M Salido, Leonardo N Servalli, Juan Carlos Gomez, Claudio Verrastro
The amount of available rhodopsin on the photoreceptor outer segment and its change over time is not considered in classic models of phototransduction. Thus, those models do not take into account the absorptance variation of the outer segment under different brightness conditions. The relationship between the light absorbed by a medium and its absorptance is well described by the Beer-Lambert law. This newly proposed model implements the absorptance variation phenomenon in a set of equations that admit photons per second as input and results in active rhodopsins per second as output...
January 13, 2017: Vision Research
https://www.readbyqxmd.com/read/28056653/a-statistical-physics-perspective-to-understand-social-visual-attention-in-autism-spectrum-disorder
#10
Alessio Liberati, Roberta Fadda, Giuseppe Doneddu, Sara Congiu, Marco A Javarone, Tricia Striano, Alessandro Chessa
This study investigated social visual attention in children with Autism Spectrum Disorder (ASD) and with typical development (TD) in the light of Brockmann and Geisel's model of visual attention. The probability distribution of gaze movements and clustering of gaze points, registered with eye-tracking technology, was studied during a free visual exploration of a gaze stimulus. A data-driven analysis of the distribution of eye movements was chosen to overcome any possible methodological problems related to the subjective expectations of the experimenters about the informative contents of the image in addition to a computational model to simulate group differences...
January 1, 2017: Perception
https://www.readbyqxmd.com/read/28056651/proximal-stimulus-for-brewster-s-phenomenon-is-equivalent-to-that-of-wheatstone-s-stereogram
#11
Hiroshi Ono, Linda Lillakas
We examined Brewster's perceptual phenomenon that is produced by the same binocularly equivalent proximal stimulus as Wheatstone's stereogram. We then constructed and observed the perceptual effect created by another distal stimulus that also created an equivalent binocular proximal stimulus. All three stimulus situations produced the appearance of a tilted line in the median plane which is consistent with Hering's rule that the average of the two local signs and binocular eye position determine visual direction...
January 1, 2017: Perception
https://www.readbyqxmd.com/read/28052734/motor-timing-intraindividual-variability-in-amnestic-mild-cognitive-impairment-and-cognitively-intact-elders-at-genetic-risk-for-alzheimer-s-disease
#12
Christina D Kay, Michael Seidenberg, Sally Durgerian, Kristy A Nielson, J Carson Smith, John L Woodard, Stephen M Rao
INTRODUCTION: Intraindividual variability (IIV) in motor performance has been shown to predict future cognitive decline. The apolipoprotein E-epsilon 4 (APOE-ε4) allele is also a well-established risk factor for memory decline. Here, we present novel findings examining the influence of the APOE-ε4 allele on the performance of asymptomatic healthy elders in comparison to individuals with amnestic MCI (aMCI) on a fine motor synchronization, paced finger-tapping task (PFTT). METHOD: Two Alzheimer's disease (AD) risk groups, individuals with aMCI (n = 24) and cognitively intact APOE-ε4 carriers (n = 41), and a control group consisting of cognitively intact APOE-ε4 noncarriers (n = 65) completed the Rey Auditory Verbal Learning Test and the PFTT, which requires index finger tapping in synchrony with a visual stimulus (interstimulus interval = 333 ms)...
January 4, 2017: Journal of Clinical and Experimental Neuropsychology
https://www.readbyqxmd.com/read/28018282/perceived-duration-increases-with-contrast-but-only-a-little
#13
Christopher P Benton, Annabelle S Redfern
Recent adaptation studies provide evidence for early visual areas playing a role in duration perception. One explanation for the pronounced duration compression commonly found with adaptation is that it reflects adaptation-driven stimulus-specific reduction in neural activity in early visual areas. If this level of stimulus-associated neural activity does drive duration, then we would expect a strong effect of contrast on perceived duration as electrophysiological studies shows neural activity in early visual areas to be strongly related to contrast...
2016: Frontiers in Psychology
https://www.readbyqxmd.com/read/27993692/suboptimal-choice-in-rats-incentive-salience-attribution-promotes-maladaptive-decision-making
#14
Jonathan J Chow, Aaron P Smith, A George Wilson, Thomas R Zentall, Joshua S Beckmann
Stimuli that are more predictive of subsequent reward also function as better conditioned reinforcers. Moreover, stimuli attributed with incentive salience function as more robust conditioned reinforcers. Some theories have suggested that conditioned reinforcement plays an important role in promoting suboptimal choice behavior, like gambling. The present experiments examined how different stimuli, those attributed with incentive salience versus those without, can function in tandem with stimulus-reward predictive utility to promote maladaptive decision-making in rats...
March 1, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/27991426/psychophysical-correspondence-between-vibrotactile-intensity-and-intracortical-microstimulation-for-tactile-neuroprostheses-in-rats
#15
İsmail Devecioğlu, Burak Güçlü
OBJECTIVE: Recent studies showed that intracortical microstimulation (ICMS) generates artificial sensations which can be utilized as somatosensory feedback in cortical neuroprostheses. To mimic the natural psychophysical response, ICMS parameters are modulated according to psychometric equivalence functions (PEFs). PEFs match the intensity levels of ICMS and mechanical stimuli, which elicit equal detection probabilities, but they typically do not include the frequency as a control variable...
December 19, 2016: Journal of Neural Engineering
https://www.readbyqxmd.com/read/27936821/chrysippus-s-pigeon-exclusion-based-responding-in-an-avian-model
#16
Marisol C Lauffer, Leyre Castro, Edward A Wasserman
Inference by exclusion can be exhibited by deductively responding to new stimuli that are presented in the context of familiar stimuli. We investigated exclusion-based responding in pigeons using a 2-alternative forced-choice discrimination task. In Phase 1, pigeons learned to associate 2 stimuli (A and B) with Response 1 and 2 stimuli (C and D) with Response 2. Following successful acquisition of these stimulus-response pairings, pigeons advanced to Phase 2, in which stimuli A and B were now reassigned to Response 2...
December 12, 2016: Journal of Experimental Psychology. Animal Learning and Cognition
https://www.readbyqxmd.com/read/27915105/the-effects-of-sleep-restriction-and-sleep-deprivation-in-producing-false-memories
#17
Alex Chatburn, Mark J Kohler, Jessica D Payne, Sean P A Drummond
False memory has been claimed to be the result of an associative process of generalisation, as well as to be representative of memory errors. These can occur at any stage of memory encoding, consolidation, or retrieval, albeit through varied mechanisms. The aim of this paper is to experimentally determine: (i) if cognitive dysfunction brought about by sleep loss at the time of stimulus encoding can influence false memory production; and (ii) whether this relationship holds across sensory modalities. Subjects undertook both the Deese-Roedigger-McDermott (DRM) false memory task and a visual task designed to produce false memories...
January 2017: Neurobiology of Learning and Memory
https://www.readbyqxmd.com/read/27914441/comparisons-of-transient-evoked-otoacoustic-emissions-using-chirp-and-click-stimuli
#18
Douglas H Keefe, M Patrick Feeney, Lisa L Hunter, Denis F Fitzpatrick
Transient-evoked otoacoustic emission (TEOAE) responses (0.7-8 kHz) were measured in normal-hearing adult ears using click stimuli and chirps whose local frequency increased or decreased linearly with time over the stimulus duration. Chirp stimuli were created by allpass filtering a click with relatively constant incident pressure level over frequency. Chirp TEOAEs were analyzed as a nonlinear residual signal by inverse allpass filtering each chirp response into an equivalent click response. Multi-window spectral and temporal averaging reduced noise levels compared to a single-window average...
September 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27908085/age-effects-in-discrimination-of-intervals-within-accented-tone-sequences-differing-in-accent-type-and-sequence-presentation-rate
#19
Peter J Fitzgibbons, Sandra Gordon-Salant
The study measured listener sensitivity to increments in the duration of one or two target silent intervals embedded within unaccented tone sequences and sequences that featured a single accented component. The baseline unaccented sequences consisted of six 1000-Hz 40-ms tone bursts that were separated equally by silent intervals to establish a slower tone sequence rate, with tonal inter-onset intervals (IOIs) set to 200 ms, or a faster rate with tonal IOIs set to 100 ms. Stimulus accent was created by doubling the baseline duration of a single sequence component, either the second tone burst (tonal accent), or the second tonal IOI (interval accent)...
November 2016: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/27893100/do-intense-perimetric-stimuli-saturate-the-healthy-visual-system
#20
Andrew J Anderson, Allison M McKendrick, Andrew Turpin
Purpose: A recent proposal for why glaucomatous perimetric sensitivities of approximately 15 to 19 dB or less are unreliable involves the idea that the neural response of normal retinal ganglion cells saturates for intense perimetric stimuli. A predicted consequence of this saturation is that the neural response for two different high intensity stimuli will be the same, leading to an inability to discriminate between them. We test that prediction. Methods: We used a two-interval forced-choice method of constant stimuli (7 steps, 40 presentations/step) to measure the ability of four healthy observers to discriminate between different intensity Size III perimetric stimuli at 0°, 9°, and 21° eccentricity...
November 1, 2016: Investigative Ophthalmology & Visual Science
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