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Scientific Reports Apr 2020Somatosensory processing can be probed empirically through vibrotactile psychophysical experiments. Psychophysical approaches are valuable for investigating both normal...
Somatosensory processing can be probed empirically through vibrotactile psychophysical experiments. Psychophysical approaches are valuable for investigating both normal and abnormal tactile function in healthy and clinical populations. To date, the test-retest reliability of vibrotactile detection and discrimination thresholds has yet to be established. This study sought to assess the reproducibility of vibrotactile detection and discrimination thresholds in human adults using an established vibrotactile psychophysical battery. Fifteen healthy adults underwent three repeat sessions of an eleven-task battery that measured a range of vibrotactile measures, including reaction time, detection threshold, amplitude and frequency discrimination, and temporal order judgement. Coefficients of variation and intraclass correlation coefficients (ICCs) were calculated for the measures in each task. Linear mixed-effects models were used to test for length and training effects and differences between tasks within the same domain. Reaction times were shown to be the most reproducible (ICC: ~0.9) followed by detection thresholds (ICC: ~0.7). Frequency discrimination thresholds were the least reproducible (ICC: ~0.3). As reported in prior studies, significant differences in measures between related tasks were also found, demonstrating the reproducibility of task-related effects. These findings show that vibrotactile detection and discrimination thresholds are reliable, further supporting the use of psychophysical experiments to probe tactile function.
Topics: Adolescent; Adult; Discrimination, Psychological; Female; Humans; Male; Physical Stimulation; Psychophysics; Reaction Time; Sensory Thresholds; Somatosensory Cortex; Touch; Touch Perception; Vibration; Young Adult
PubMed: 32300187
DOI: 10.1038/s41598-020-63208-z -
Journal of Vision Jul 2022The magnocellular (MC) pathway in the primate has much higher achromatic contrast sensitivity than the parvocellular (PC) pathway, and is implicated in luminance...
The magnocellular (MC) pathway in the primate has much higher achromatic contrast sensitivity than the parvocellular (PC) pathway, and is implicated in luminance contrast detection. But MC pathway responses tend to saturate at lower achromatic contrast than do PC pathway responses. It has been proposed that the PC pathway plays a major role in discriminating suprathreshold achromatic contrast, because the MC pathway is in saturation. This has been termed the pulsed-pedestal protocol. To test this hypothesis, responses of MC and PC pathway ganglion cells have been examined under suprathreshold conditions with stimulus configurations similar to those in psychophysical tests. For MC cells, response saturation was much less for flashed or moving edges than for sinusoidal modulation, and MC cell thresholds predicted for these stimuli were similar to psychophysical discrimination (and detection) data. Results suggest the protocol is not effective in segregating MC and PC function.
Topics: Animals; Contrast Sensitivity; Neurons; Photic Stimulation; Psychophysics; Visual Pathways
PubMed: 35848903
DOI: 10.1167/jov.22.8.11 -
Current Opinion in Neurobiology Aug 2008The external world is mapped retinotopically onto the primary visual cortex (V1). We show here that objects in the world, unless they are very dissimilar, can be... (Review)
Review
The external world is mapped retinotopically onto the primary visual cortex (V1). We show here that objects in the world, unless they are very dissimilar, can be recognized only if they are sufficiently separated in visual cortex: specifically, in V1, at least 6mm apart in the radial direction (increasing eccentricity) or 1mm apart in the circumferential direction (equal eccentricity). Objects closer together than this critical spacing are perceived as an unidentifiable jumble. This is called 'crowding'. It severely limits visual processing, including speed of reading and searching. The conclusion about visual cortex rests on three findings. First, psychophysically, the necessary 'critical' spacing, in the visual field, is proportional to (roughly half) the eccentricity of the objects. Second, the critical spacing is independent of the size and kind of object. Third, anatomically, the representation of the visual field on the cortical surface is such that the position in V1 (and several other areas) is the logarithm of eccentricity in the visual field. Furthermore, we show that much of this can be accounted for by supposing that each 'combining field', defined by the critical spacing measurements, is implemented by a fixed number of cortical neurons.
Topics: Animals; Brain Mapping; Cerebral Cortex; Discrimination, Psychological; Humans; Neurons; Psychophysics; Space Perception; Visual Cortex; Visual Perception
PubMed: 18835355
DOI: 10.1016/j.conb.2008.09.008 -
Journal of Vision Oct 2017A large part of classical visual psychophysics was concerned with the fundamental question of how pattern information is initially encoded in the human visual system....
A large part of classical visual psychophysics was concerned with the fundamental question of how pattern information is initially encoded in the human visual system. From these studies a relatively standard model of early spatial vision emerged, based on spatial frequency and orientation-specific channels followed by an accelerating nonlinearity and divisive normalization: contrast gain-control. Here we implement such a model in an image-computable way, allowing it to take arbitrary luminance images as input. Testing our implementation on classical psychophysical data, we find that it explains contrast detection data including the ModelFest data, contrast discrimination data, and oblique masking data, using a single set of parameters. Leveraging the advantage of an image-computable model, we test our model against a recent dataset using natural images as masks. We find that the model explains these data reasonably well, too. To explain data obtained at different presentation durations, our model requires different parameters to achieve an acceptable fit. In addition, we show that contrast gain-control with the fitted parameters results in a very sparse encoding of luminance information, in line with notions from efficient coding. Translating the standard early spatial vision model to be image-computable resulted in two further insights: First, the nonlinear processing requires a denser sampling of spatial frequency and orientation than optimal coding suggests. Second, the normalization needs to be fairly local in space to fit the data obtained with natural image masks. Finally, our image-computable model can serve as tool in future quantitative analyses: It allows optimized stimuli to be used to test the model and variants of it, with potential applications as an image-quality metric. In addition, it may serve as a building block for models of higher level processing.
Topics: Computer Simulation; Contrast Sensitivity; Humans; Orientation; Pattern Recognition, Visual; Psychophysics; Space Perception; Spatial Navigation
PubMed: 29053781
DOI: 10.1167/17.12.12 -
Journal of Vision Dec 2018Continuous psychophysics is a newly developed technique that allows rapid estimation of visual thresholds by asking subjects to track a moving object, then deriving the...
Continuous psychophysics is a newly developed technique that allows rapid estimation of visual thresholds by asking subjects to track a moving object, then deriving the integration window underlying tracking behavior (Bonnen, Burge, Yates, Pillow, & Cormack, 2015). Leveraging the continuous flow of stimuli and responses, continuous psychophysics allows for estimation of psychophysical thresholds in as little as 1 min. To date this technique has been applied only to tracking visual objects, where it has been used to measure localization thresholds. Here we adapt the technique to visual motion discrimination, by displaying a drifting grating that changes direction on a binary random walk and asking participants to continuously report drift direction by alternate key press. This technique replicates and confirms well-known findings of the motion-perception system. It also proves particularly valuable in demonstrating induced motion, reinforcing evidence for the existence of antagonistic surround fields. At low contrasts, the surround summates with the center, rather than opposing it, again consistent with existing evidence on classical techniques. The user-friendliness and efficiency of the method may lend it to clinical and developmental work.
Topics: Female; Humans; Male; Motion Perception; Pattern Recognition, Visual; Photic Stimulation; Psychophysics; Sensory Thresholds; Young Adult
PubMed: 30535256
DOI: 10.1167/18.13.7 -
The Journal of Neuroscience : the... Aug 2009Communicating with one's environment requires efficient neural interaction between action and perception. Neural substrates of sound perception and production are... (Comparative Study)
Comparative Study
Communicating with one's environment requires efficient neural interaction between action and perception. Neural substrates of sound perception and production are connected by the arcuate fasciculus (AF). Although AF is known to be involved in language, its roles in non-linguistic functions are unexplored. Here, we show that tone-deaf people, with impaired sound perception and production, have reduced AF connectivity. Diffusion tensor tractography and psychophysics were assessed in tone-deaf individuals and matched controls. Abnormally reduced AF connectivity was observed in the tone deaf. Furthermore, we observed relationships between AF and auditory-motor behavior: superior and inferior AF branches predict psychophysically assessed pitch discrimination and sound production perception abilities, respectively. This neural abnormality suggests that tone deafness leads to a reduction in connectivity resulting in pitch-related impairments. Results support a dual-stream anatomy of sound production and perception implicated in vocal communications. By identifying white matter differences and their psychophysical correlates, results contribute to our understanding of how neural connectivity subserves behavior.
Topics: Acoustic Stimulation; Adult; Auditory Perception; Deafness; Female; Humans; Male; Middle Aged; Pitch Discrimination; Pitch Perception; Psychophysics; Syndrome
PubMed: 19692596
DOI: 10.1523/JNEUROSCI.1701-09.2009 -
Perception 1996
Topics: Humans; Models, Biological; Perception; Psychological Theory; Psychophysics; Research Design; Signal Detection, Psychological
PubMed: 8888296
DOI: 10.1068/p250629 -
Perception 2002
Topics: History, 19th Century; History, 20th Century; Humans; Motion Perception; Optical Illusions; Psychophysics
PubMed: 12430944
DOI: 10.1068/p3110ed -
Scientific Reports Feb 2022For a certain kind of decision event, the decision maker does not know the internal mechanism and knowledge information of the decision events.When this kind of decision...
For a certain kind of decision event, the decision maker does not know the internal mechanism and knowledge information of the decision events.When this kind of decision events gives multiple selection branches, it is found that there is a decision psychological tendency to find the most common features by comparing the selection branches. Based on this, a zero-knowledge decision making (ZKDM) method is proposed. By defining the feature points and feature sets of the selection branches of the decision events, the characteristic moments of the system are constructed and the branch with the most common characteristics is obtained. It is observed that through the findings of investigation the probability of arriving at the correct choice based on the ZKDM method is high. The effectiveness of the ZKDM method may be related to the fact that the designers of decision events usually determine the correct selection branch first, before changing it to design other branches. A questionnaire survey of 279 respondents reveals that more than half of them actually adopt such a design idea. Furthermore, a separate questionnaire survey of 465 decision-makers reveal that 19.14% of the respondents clearly adopt ZKDM.
Topics: Choice Behavior; Decision Making; Humans; Intuition; Knowledge; Psychophysics; Surveys and Questionnaires
PubMed: 35210448
DOI: 10.1038/s41598-022-06753-z -
Nature Communications Aug 2018Goal-directed behavior depends on both sensory mechanisms that gather information from the outside world and decision-making mechanisms that select appropriate behavior...
Goal-directed behavior depends on both sensory mechanisms that gather information from the outside world and decision-making mechanisms that select appropriate behavior based on that sensory information. Psychophysical reverse correlation is commonly used to quantify how fluctuations of sensory stimuli influence behavior and is generally believed to uncover the spatiotemporal weighting functions of sensory processes. Here we show that reverse correlations also reflect decision-making processes and can deviate significantly from the true sensory filters. Specifically, changes of decision bound and mechanisms of evidence integration systematically alter psychophysical reverse correlations. Similarly, trial-to-trial variability of sensory and motor delays and decision times causes systematic distortions in psychophysical kernels that should not be attributed to sensory mechanisms. We show that ignoring details of the decision-making process results in misinterpretation of reverse correlations, but proper use of these details turns reverse correlation into a powerful method for studying both sensory and decision-making mechanisms.
Topics: Auditory Perception; Cognition; Decision Making; Humans; Models, Neurological; Psychomotor Performance; Psychophysics
PubMed: 30154467
DOI: 10.1038/s41467-018-05797-y