-
Neuron Aug 2022Repeated application of noxious stimuli leads to a progressively increased pain perception; this temporal summation is enhanced in and predictive of clinical pain...
Repeated application of noxious stimuli leads to a progressively increased pain perception; this temporal summation is enhanced in and predictive of clinical pain disorders. Its electrophysiological correlate is "wind-up," in which dorsal horn spinal neurons increase their response to repeated nociceptor stimulation. To understand the genetic basis of temporal summation, we undertook a GWAS of wind-up in healthy human volunteers and found significant association with SLC8A3 encoding sodium-calcium exchanger type 3 (NCX3). NCX3 was expressed in mouse dorsal horn neurons, and mice lacking NCX3 showed normal, acute pain but hypersensitivity to the second phase of the formalin test and chronic constriction injury. Dorsal horn neurons lacking NCX3 showed increased intracellular calcium following repetitive stimulation, slowed calcium clearance, and increased wind-up. Moreover, virally mediated enhanced spinal expression of NCX3 reduced central sensitization. Our study highlights Ca efflux as a pathway underlying temporal summation and persistent pain, which may be amenable to therapeutic targeting.
Topics: Animals; Calcium; Humans; Mice; Pain; Posterior Horn Cells; Psychophysics; Sodium-Calcium Exchanger
PubMed: 35705078
DOI: 10.1016/j.neuron.2022.05.017 -
Psychonomic Bulletin & Review Feb 2022Attention operates as a cognitive gate that selects sensory information for entry into memory and awareness (Driver, 2001, British Journal of Psychology, 92, 53-78)....
Attention operates as a cognitive gate that selects sensory information for entry into memory and awareness (Driver, 2001, British Journal of Psychology, 92, 53-78). Under many circumstances, the selected information is task-relevant and important to remember, but sometimes perceptually salient nontarget objects will capture attention and enter into awareness despite their irrelevance (Adams & Gaspelin, 2020, Attention, Perception, & Psychophysics, 82[4], 1586-1598). Recent studies have shown that repeated exposures with salient distractor will diminish their ability to capture attention, but the relationship between suppression and later cognitive processes such as memory and awareness remains unclear. If learned attentional suppression (indicated by reduced capture costs) occurs at the sensory level and prevents readout to other cognitive processes, one would expect memory and awareness to dimmish commensurate with improved suppression. Here, we test this hypothesis by measuring memory precision and awareness of salient nontargets over repeated exposures as capture costs decreased. Our results show that stronger learned suppression is accompanied by reductions in memory precision and confidence in having seen a color singleton at all, suggesting that such suppression operates at the sensory level to prevent further processing of the distractor object.
Topics: Attention; Data Collection; Humans; Learning; Psychophysics; Reaction Time
PubMed: 34322846
DOI: 10.3758/s13423-021-01968-z -
Nature Communications Dec 2022Identifying the structure of motion relations in the environment is critical for navigation, tracking, prediction, and pursuit. Yet, little is known about the mental and...
Identifying the structure of motion relations in the environment is critical for navigation, tracking, prediction, and pursuit. Yet, little is known about the mental and neural computations that allow the visual system to infer this structure online from a volatile stream of visual information. We propose online hierarchical Bayesian inference as a principled solution for how the brain might solve this complex perceptual task. We derive an online Expectation-Maximization algorithm that explains human percepts qualitatively and quantitatively for a diverse set of stimuli, covering classical psychophysics experiments, ambiguous motion scenes, and illusory motion displays. We thereby identify normative explanations for the origin of human motion structure perception and make testable predictions for future psychophysics experiments. The proposed online hierarchical inference model furthermore affords a neural network implementation which shares properties with motion-sensitive cortical areas and motivates targeted experiments to reveal the neural representations of latent structure.
Topics: Humans; Motion Perception; Bayes Theorem; Visual Perception; Motion; Psychophysics
PubMed: 36456546
DOI: 10.1038/s41467-022-34805-5 -
Investigative Ophthalmology & Visual... Jan 2022We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction.
PURPOSE
We developed a stereo task that is based on a motion direction discrimination to examine the role that depth can play in disambiguating motion direction.
METHODS
In this study, we quantified normal adults' static and dynamic (i.e., laterally moving) stereoscopic performance using a psychophysical task, where we dichoptically presented randomly arranged, limited lifetime Gabor elements at two depth planes (one plane was at the fixation plane and the other at an uncrossed disparity relative to the fixation plane). Each plane contained half of the elements. For the dynamic condition, all elements were vertically oriented and moved to the left in one plane and to the right in another plane; for the static condition, the elements were horizontally oriented in one plane and vertically oriented in another plane.
RESULTS
For the range of motion speed that we measured (from 0.17°/s to 5.33°/s), we observed clear speed tuning of the stereo sensitivity (P = 3.0 × 10-5). The shape of this tuning did not significantly change with different spatial frequencies. We also found a significant difference in stereo sensitivity between stereopsis with static and laterally moving stimuli (speed = 0.67°/s; P = 0.004). Such difference was not evident when we matched the task between the static and moving stimuli.
CONCLUSIONS
We report that lateral motion modulates human global depth perception. This motion/stereo constraint is related to motion velocity not stimulus temporal frequency. We speculate that the processing of motion-based stereopsis of the kind reported here occurs in dorsal extrastriate cortex.
Topics: Adult; Depth Perception; Female; Humans; Male; Motion Perception; Psychophysics; Reference Values; Vision Disparity; Vision, Binocular; Visual Cortex; Young Adult
PubMed: 35077551
DOI: 10.1167/iovs.63.1.32 -
Journal of the Association For Research... Aug 2022We describe a scalp-recorded measure of tonotopic selectivity, the "cortical onset response" (COR) and compare the results between humans and cats. The COR results, in...
We describe a scalp-recorded measure of tonotopic selectivity, the "cortical onset response" (COR) and compare the results between humans and cats. The COR results, in turn, were compared with psychophysical masked-detection thresholds obtained using similar stimuli and obtained from both species. The COR consisted of averaged responses elicited by 50-ms tone-burst probes presented at 1-s intervals against a continuous noise masker. The noise masker had a bandwidth of 1 or 1/8th octave, geometrically centred on 4000 Hz for humans and on 8000 Hz for cats. The probe frequency was either - 0.5, - 0.25, 0, 0.25 or 0.5 octaves re the masker centre frequency. The COR was larger for probe frequencies more distant from the centre frequency of the masker, and this effect was greater for the 1/8th-octave than for the 1-octave masker. This pattern broadly reflected the masked excitation patterns obtained psychophysically with similar stimuli in both species. However, the positive signal-to-noise ratio used to obtain reliable COR measures meant that some aspects of the data differed from those obtained psychophysically, in a way that could be partly explained by the upward spread of the probe's excitation pattern. Our psychophysical measurements also showed that the auditory filter width obtained at 8000 Hz using notched-noise maskers was slightly wider in cat than previous measures from humans. We argue that although conclusions from COR measures differ in some ways from conclusions based on psychophysics, the COR measures provide an objective, noninvasive, valid measure of tonotopic selectivity that does not require training and that may be applied to acoustic and cochlear-implant experiments in humans and laboratory animals.
Topics: Animals; Auditory Threshold; Cats; Electrophysiology; Humans; Noise; Perceptual Masking; Psychophysics
PubMed: 35697952
DOI: 10.1007/s10162-022-00851-5 -
Journal of Vision Feb 2021Categorization performance is a popular metric of scene recognition and understanding in behavioral and computational research. However, categorical constructs and their...
Categorization performance is a popular metric of scene recognition and understanding in behavioral and computational research. However, categorical constructs and their labels can be somewhat arbitrary. Derived from exhaustive vocabularies of place names (e.g., Deng et al., 2009), or the judgements of small groups of researchers (e.g., Fei-Fei, Iyer, Koch, & Perona, 2007), these categories may not correspond with human-preferred taxonomies. Here, we propose clustering by increasing the rand index via coordinate ascent (CIRCA): an unsupervised, data-driven clustering method for deriving ground-truth scene categories. In Experiment 1, human participants organized 80 stereoscopic images of outdoor scenes from the Southampton-York Natural Scenes (SYNS) dataset (Adams et al., 2016) into discrete categories. In separate tasks, images were grouped according to i) semantic content, ii) three-dimensional spatial structure, or iii) two-dimensional image appearance. Participants provided text labels for each group. Using the CIRCA method, we determined the most representative category structure and then derived category labels for each task/dimension. In Experiment 2, we found that these categories generalized well to a larger set of SYNS images, and new observers. In Experiment 3, we tested the relationship between our category systems and the spatial envelope model (Oliva & Torralba, 2001). Finally, in Experiment 4, we validated CIRCA on a larger, independent dataset of same-different category judgements. The derived category systems outperformed the SUN taxonomy (Xiao, Hays, Ehinger, Oliva, & Torralba, 2010) and an alternative clustering method (Greene, 2019). In summary, we believe this novel categorization method can be applied to a wide range of datasets to derive optimal categorical groupings and labels from psychophysical judgements of stimulus similarity.
Topics: Adolescent; Adult; Attention; Female; Humans; Judgment; Male; Pattern Recognition, Visual; Psychophysics; Recognition, Psychology; Visual Cortex; Young Adult
PubMed: 33595646
DOI: 10.1167/jov.21.2.8 -
PloS One 2021We often take people's ability to understand and produce line drawings for granted. But where should we draw lines, and why? We address psychological principles that...
We often take people's ability to understand and produce line drawings for granted. But where should we draw lines, and why? We address psychological principles that underlie efficient representations of complex information in line drawings. First, 58 participants with varying degree of artistic experience produced multiple drawings of a small set of scenes by tracing contours on a digital tablet. Second, 37 independent observers ranked the drawings by how representative they are of the original photograph. Matching contours between drawings of the same scene revealed that the most consistently drawn contours tend to be drawn earlier. We generated half-images with the most- versus least-consistently drawn contours and asked 25 observers categorize the quickly presented scenes. Observers performed significantly better for the most compared to the least consistent half-images. The most consistently drawn contours were more likely to depict occlusion boundaries, whereas the least consistently drawn contours frequently depicted surface normals.
Topics: Adolescent; Adult; Computer Graphics; Female; Form Perception; Humans; Linear Models; Male; Middle Aged; Pattern Recognition, Visual; Photography; Psychophysics; Vision, Ocular; Visual Perception; Young Adult
PubMed: 34748556
DOI: 10.1371/journal.pone.0258376 -
Vision Research Nov 2021Center-surround antagonism, as a ubiquitous feature in visual processing, usually leads to inferior perception for a large stimulus compared to a small one. For example,...
Center-surround antagonism, as a ubiquitous feature in visual processing, usually leads to inferior perception for a large stimulus compared to a small one. For example, it is more difficult to judge the motion direction of a large high-contrast pattern than that of a small one. However, this spatial suppression in the motion dimension was only reported for luminance motion, and was not found for chromatic motion. Given that center-surround suppression only occurs for strong visual inputs, we hypothesized that previous failure in finding spatial suppression of chromatic motion might be due to weak chromatic motion being induced with stimuli of limited parameters. In this study, we used phase-shift discrimination and motion-direction discrimination tasks to measure motion spatial suppression induced by stimuli of two spatial frequencies (0.5 and 2 cpd) and two contrasts (low and high). We found that spatial suppression of the chromatic motion was stably observed for stimuli of high spatial frequency (2 cpd) and high contrast and spatial summation occurred for stimuli of low spatial frequency (0.5 cpd). Intriguingly, there was no correlations between the motion spatial suppressions of luminance motion and chromatic motion, implying that the two types of spatial suppression are not originated from the same neural processing. Our findings indicate that spatial suppression also exists for chromatic motion, and the mechanisms underlying the spatial suppression of chromatic motion is different from that of luminance motion.
Topics: Color Perception; Contrast Sensitivity; Humans; Motion; Motion Perception; Psychophysics; Visual Perception
PubMed: 34385078
DOI: 10.1016/j.visres.2021.07.014 -
Translational Psychiatry Aug 2022It has been widely demonstrated that time processing is altered in patients with schizophrenia. This perspective review delves into such temporal deficit and highlights... (Review)
Review
It has been widely demonstrated that time processing is altered in patients with schizophrenia. This perspective review delves into such temporal deficit and highlights its link to low-level sensory alterations, which are often overlooked in rehabilitation protocols for psychosis. However, if temporal impairment at the sensory level is inherent to the disease, new interventions should focus on this dimension. Beyond more traditional types of intervention, here we review the most recent digital technologies for rehabilitation and the most promising ones for sensory training. The overall aim is to synthesise existing literature on time in schizophrenia linking psychopathology, psychophysics, and technology to help future developments.
Topics: Humans; Psychopathology; Psychophysics; Psychotic Disorders; Schizophrenia; Technology
PubMed: 35961974
DOI: 10.1038/s41398-022-02101-x -
Annual Review of Vision Science Sep 2019We are sad to report that Professor Jacob (Jack) Nachmias passed away on March 2, 2019. Nachmias was born in Athens, Greece, on June 9, 1928. To escape the Nazis, he and...
We are sad to report that Professor Jacob (Jack) Nachmias passed away on March 2, 2019. Nachmias was born in Athens, Greece, on June 9, 1928. To escape the Nazis, he and his family came to the United States in 1939. He received his undergraduate degree from Cornell University and then an MA from Swarthmore College, where he worked with Hans Wallach and Wolfgang Kohler; his PhD in Psychology was from Harvard University. Nachmias spent the majority of his career as a Professor of Psychology at the University of Pennsylvania. He made fundamental contributions to our understanding of vision, most notably through the study of eye movements, the development of signal detection theory and forced-choice psychophysical methods, and the psychophysical characterization of spatial-frequency-selective visual channels. Nachmias' work was recognized by his election to the National Academy of Sciences and receipt of the Optical Society's Tillyer Award.
Topics: Eye Movements; Greece; History, 20th Century; History, 21st Century; Humans; Ophthalmology; Psychology; Psychophysics; Signal Detection, Psychological; United States; Visual Perception
PubMed: 31283448
DOI: 10.1146/annurev-vision-011019-111539