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Vision Research Jan 2020Adaptation is the process that changes a neuron's response based on recent inputs. In the traditional model, a neuron's state of adaptation depends on the recent input...
Adaptation is the process that changes a neuron's response based on recent inputs. In the traditional model, a neuron's state of adaptation depends on the recent input to that neuron alone, whereas in a recently introduced model (Hebbian normalization), adaptation depends on the structure of neural correlated firing. In particular, increased response products between pairs of neurons leads to increased mutual suppression. We test a psychophysical prediction of this model: adaptation should depend on 2nd-order statistics of input stimuli. That is, if two stimuli excite two distinct sub-populations of neurons, then presenting those stimuli simultaneously during adaptation should strengthen mutual suppression between those subpopulations. We confirm this prediction in two experiments. In the first, pairing two gratings synchronously during adaptation (i.e., a plaid) rather than asynchronously (interleaving the two gratings in time) leads to increased effectiveness of one pattern for masking the other. In the second, pairing the gratings in a center-surround configuration results in reduced apparent contrast for the central grating when paired with the same surround (as compared with a condition in which the central grating appears with a different surround at test than during adaptation). These results are consistent with the prediction that an increase in response covariance leads to greater mutual suppression between neurons. This effect is detectable both at threshold (masking) and well above threshold (apparent contrast).
Topics: Adaptation, Physiological; Adult; Female; Humans; Male; Models, Neurological; Neurons; Perceptual Masking; Visual Cortex; Visual Perception; Young Adult
PubMed: 31862645
DOI: 10.1016/j.visres.2019.11.004 -
Hearing Research Jul 2022Behavioral forward-masking thresholds with a spectrally notched-noise masker and a fixed low-level probe tone have been shown to provide accurate estimates of cochlear...
Behavioral forward-masking thresholds with a spectrally notched-noise masker and a fixed low-level probe tone have been shown to provide accurate estimates of cochlear tuning. Estimates using simultaneous masking are similar but generally broader, presumably due to nonlinear cochlear suppression effects. So far, estimates with forward masking have been limited to frequencies of 1 kHz and above. This study used spectrally notched noise under forward and simultaneous masking to estimate frequency selectivity between 200 and 1000 Hz for young adult listeners with normal hearing. Estimates of filter tuning at 1000 Hz were in agreement with previous studies. Estimated tuning broadened below 1000 Hz, with the filter quality factor based on the equivalent rectangular bandwidth (Q) decreasing more rapidly with decreasing frequency than predicted by previous equations, in line with earlier predictions based on otoacoustic-emission latencies. Estimates from simultaneous masking remained broader than those from forward masking by approximately the same ratio. The new data provide a way to compare human cochlear tuning estimates with auditory-nerve tuning curves from other species across most of the auditory frequency range.
Topics: Auditory Threshold; Cochlea; Cochlear Nerve; Humans; Noise; Perceptual Masking; Young Adult
PubMed: 35405591
DOI: 10.1016/j.heares.2022.108500 -
Journal of Vision Oct 2016Perception is shaped not only by current sensory inputs but also by expectations generated from past sensory experience. Humans viewing ambiguous stimuli in a stable...
Perception is shaped not only by current sensory inputs but also by expectations generated from past sensory experience. Humans viewing ambiguous stimuli in a stable visual environment are generally more likely to see the perceptual interpretation that matches their expectations, but it is less clear how expectations affect perception when the environment is changing predictably. We used statistical learning to teach observers arbitrary sequences of natural images and employed binocular rivalry to measure perceptual selection as a function of predictive context. In contrast to previous demonstrations of preferential selection of predicted images for conscious awareness, we found that recently acquired sequence predictions biased perceptual selection toward unexpected natural images and image categories. These perceptual biases were not associated with explicit recall of the learned image sequences. Our results show that exposure to arbitrary sequential structure in the environment impacts subsequent visual perceptual selection and awareness. Specifically, for natural image sequences, the visual system prioritizes what is surprising, or statistically informative, over what is expected, or statistically likely.
Topics: Adolescent; Adult; Awareness; Biometry; Female; Humans; Male; Perceptual Masking; Vision Disparity; Vision, Binocular; Visual Perception; Young Adult
PubMed: 27802512
DOI: 10.1167/16.13.6 -
Proceedings of the National Academy of... Jul 2021Recurrent loops in the visual cortex play a critical role in visual perception, which is likely not mediated by purely feed-forward pathways. However, the development of...
Recurrent loops in the visual cortex play a critical role in visual perception, which is likely not mediated by purely feed-forward pathways. However, the development of recurrent loops is poorly understood. The role of recurrent processing has been studied using visual backward masking, a perceptual phenomenon in which a visual stimulus is rendered invisible by a following mask, possibly because of the disruption of recurrent processing. Anatomical studies have reported that recurrent pathways are immature in early infancy. This raises the possibility that younger infants process visual information mainly in a feed-forward manner, and thus, they might be able to perceive visual stimuli that adults cannot see because of backward masking. Here, we show that infants under 7 mo of age are immune to visual backward masking and that masked stimuli remain visible to younger infants while older infants cannot perceive them. These results suggest that recurrent processing is immature in infants under 7 mo and that they are able to perceive objects even without recurrent processing. Our findings indicate that the algorithm for visual perception drastically changes in the second half of the first year of life.
Topics: Facial Recognition; Female; Form Perception; Humans; Infant; Male; Perceptual Masking; Photic Stimulation; Reproducibility of Results; Visual Perception
PubMed: 34162737
DOI: 10.1073/pnas.2103040118 -
Psychonomic Bulletin & Review Apr 2024Auditory categorization requires listeners to integrate acoustic information from multiple dimensions. Attentional theories suggest that acoustic dimensions that are...
Auditory categorization requires listeners to integrate acoustic information from multiple dimensions. Attentional theories suggest that acoustic dimensions that are informative attract attention and therefore receive greater perceptual weight during categorization. However, the acoustic environment is often noisy, with multiple sound sources competing for listeners' attention. Amid these adverse conditions, attentional theories predict that listeners will distribute attention more evenly across multiple dimensions. Here we test this prediction using an informational masking paradigm. In two experiments, listeners completed suprasegmental (focus) and segmental (voicing) speech categorization tasks in quiet or in the presence of competing speech. In both experiments, the target speech consisted of short words or phrases that varied in the extent to which fundamental frequency (F0) and durational information signalled category identity. To isolate effects of informational masking, target and competing speech were presented in opposite ears. Across both experiments, there was substantial individual variability in the relative weighting of the two dimensions. These individual differences were consistent across listening conditions, suggesting that they reflect stable perceptual strategies. Consistent with attentional theories of auditory categorization, listeners who relied on a single primary dimension in quiet shifted towards integrating across multiple dimensions in the presence of competing speech. These findings demonstrate that listeners make greater use of the redundancy present in speech when attentional resources are limited.
Topics: Humans; Speech Perception; Perceptual Masking; Attention; Adult; Young Adult; Female; Male
PubMed: 37658222
DOI: 10.3758/s13423-023-02364-5 -
Communications Biology Oct 2022Sound in noise is better detected or understood if target and masking sources originate from different locations. Mammalian physiology suggests that the...
Sound in noise is better detected or understood if target and masking sources originate from different locations. Mammalian physiology suggests that the neurocomputational process that underlies this binaural unmasking is based on two hemispheric channels that encode interaural differences in their relative neuronal activity. Here, we introduce a mathematical formulation of the two-channel model - the complex-valued correlation coefficient. We show that this formulation quantifies the amount of temporal fluctuations in interaural differences, which we suggest underlie binaural unmasking. We applied this model to an extensive library of psychoacoustic experiments, accounting for 98% of the variance across eight studies. Combining physiological plausibility with its success in explaining behavioral data, the proposed mechanism is a significant step towards a unified understanding of binaural unmasking and the encoding of interaural differences in general.
Topics: Humans; Perceptual Masking; Auditory Threshold; Noise; Sound
PubMed: 36273085
DOI: 10.1038/s42003-022-04098-x -
Journal of Vision Jun 2010We measured the strength and optimal target-mask onset asynchrony (SOA(max)) of metacontrast masking using Gabor patches as targets and sinusoidal rings with Gaussian... (Comparative Study)
Comparative Study
We measured the strength and optimal target-mask onset asynchrony (SOA(max)) of metacontrast masking using Gabor patches as targets and sinusoidal rings with Gaussian envelopes as masks. We varied spatial frequencies (f) between 0.5 and 8 cpd to manipulate the degree to which spatial frequency channels in the visual system are triggered. By varying spatial frequencies as well as spatial frequency contrast (Δf) between target and mask, we measured the properties of inter- as well as intra-channel inhibition. We found that an increase of the mask's spatial frequency decreased its effectiveness but did not change its SOA(max). When orientation contrast was introduced between targets and masks with the same spatial frequency, SOA(max) increased with orientation contrast. An effect of orientation contrast was not observed with low spatial frequency-on-high spatial frequency masking, indicating that orientation selectivity is a unique feature of within-channel masking. Spatial frequency contrast affects SOA(max) and effectiveness in an asymmetric fashion: low-on-high masking is strong and yields a longer SOA(max), compared to low-on-low and high-on-high masking; high-on-low masking is ineffective.
Topics: Adult; Contrast Sensitivity; Female; Humans; Male; Orientation; Perceptual Masking; Space Perception; Young Adult
PubMed: 20884561
DOI: 10.1167/10.6.12 -
Journal of Vision Sep 2011Blur is an important attribute of human spatial vision, and sensitivity to blur has been the subject of considerable experimental research and theoretical modeling.... (Review)
Review
Blur is an important attribute of human spatial vision, and sensitivity to blur has been the subject of considerable experimental research and theoretical modeling. Often, these models have invoked specialized concepts or mechanisms, such as intrinsic blur, multiple spatial frequency channels, or blur estimation units. In this paper, we review the several experimental studies of blur discrimination and find that they are in broad empirical agreement. However, contrary to previous modeling efforts, we find that specialized mechanisms are not required and that the essential features of blur discrimination are fully accounted for by a visible contrast energy (ViCE) model, in which two spatial patterns are distinguished when the integrated difference between their masked local visible contrast energy responses reaches a threshold value. In the ViCE model, intrinsic blur is represented by the high-frequency limb of the contrast sensitivity function, but the low-frequency limb also contributes to the predictions for large reference blurs, and the model includes masking, which improves predictions for high-contrast stimuli.
Topics: Contrast Sensitivity; Humans; Models, Neurological; Perceptual Masking; Sensory Thresholds; Space Perception
PubMed: 21931120
DOI: 10.1167/11.5.10 -
Vision Research Apr 2005In the ultimate stage of the Adelson-Bergen motion energy model [Adelson, E. H., & Bergen, J. (1985). Spatiotemporal energy models for the perception of motion. Journal...
In the ultimate stage of the Adelson-Bergen motion energy model [Adelson, E. H., & Bergen, J. (1985). Spatiotemporal energy models for the perception of motion. Journal of the Optical Society of America, 2, 284-299], motion is derived from the difference between directionally opponent energies E(L) and E(R). However, Georgeson and Scott-Samuel [Georgeson, M. A., & Scott-Samuel, N. E. (1999). Motion contrast: A new metric for direction discrimination. Vision Research, 39, 4393-4402] demonstrated that motion contrast-a metric that normalizes opponent motion energy (E(L)-E(R)) by flicker energy (E(L)+E(R))-is a better descriptor of human direction discrimination. In a previous study [Rainville, S. J. M., Makous, W. L., & Scott-Samuel, N. E. (2002). The spatial properties of opponent-motion normalization. Vision Research, 42, 1727-1738], we used a lateral masking paradigm to show that opponent-motion normalization is selective for flicker position, orientation, and spatial-frequency. In the present study, we used a superposition masking paradigm and compared results to lateral masking data, as the two masking types activate local and remote normalization mechanisms differentially. Although selectivity for flicker orientation and spatial frequency varied across observers, bandwidths were similar across lateral and superimposed masking conditions. Additional experiments demonstrated that normalization signals are pooled over a spatial region whose aspect ratio and size are consistent with those of local motion detectors. Together, results show no evidence of remote normalization signals predicted by broadband inhibitory models [(e.g.) Heeger, D. J. (1992). Normalization of cell responses in cat striate cortex. Visual Neuroscience, 9, 181-197; Foley, J. M. (1994). Human luminance pattern-vision mechanisms: Masking experiments require a new model. Journal of the Optical Society of America A-Optics and Image Science, 11, 1710-1719] but support a local normalization process whose spatial properties are inherited from low-level motion detectors.
Topics: Flicker Fusion; Humans; Motion Perception; Perceptual Masking; Psychophysics
PubMed: 15707920
DOI: 10.1016/j.visres.2004.10.018 -
Journal of Vision Apr 2020Crowding is the deterioration of target identification in the presence of neighboring objects. Recent studies using appearance-based methods showed that the perceived...
Crowding is the deterioration of target identification in the presence of neighboring objects. Recent studies using appearance-based methods showed that the perceived number of target elements is often diminished in crowding. Here we introduce a related type of diminishment in repeating patterns (sets of parallel lines), which we term "redundancy masking." In four experiments, observers were presented with arrays of small numbers of lines centered at 10° eccentricity. The task was to indicate the number of lines. In Experiment 1, spatial characteristics of redundancy masking were examined by varying the inter-line spacing. We found that redundancy masking decreased with increasing inter-line spacing and ceased at spacings of approximately 0.25 times the eccentricity. In Experiment 2, we assessed whether the strength of redundancy masking differed between radial and tangential arrangements of elements as it does in crowding. Redundancy masking was strong with radially arranged lines (horizontally arranged vertical lines), and absent with tangentially arranged lines (vertically arranged horizontal lines). In Experiment 3, we investigated whether target size (line width and length) modulated redundancy masking. There was an effect of width: Thinner lines yielded stronger redundancy masking. We did not find any differences between the tested line lengths. In Experiment 4, we varied the regularity of the line arrays by vertically or horizontally jittering the positions of the lines. Redundancy masking was strongest with regular spacings and weakened with decreasing regularity. Our experiments show under which conditions whole items are lost in crowded displays, and how this redundancy masking resembles-and partly diverges from-crowded identification. We suggest that redundancy masking is a contributor to the deterioration of performance in crowded displays with redundant patterns.
Topics: Adult; Crowding; Female; Humans; Male; Pattern Recognition, Visual; Perceptual Masking; Visual Perception; Young Adult
PubMed: 32330230
DOI: 10.1167/jov.20.4.14