scholarly journals Rapid and Coarse Face Detection in Cortex

2017 ◽  
Author(s):  
Laura Cabral ◽  
Bobby Stojanoski ◽  
Rhodri Cusack
Keyword(s):  
Spatial Frequency ◽  
Face Processing ◽  
Rapid Detection ◽  
Reaction Times ◽  
Subcortical Structures ◽  
Detection Mechanism ◽  
Temporal Lobes ◽  
Spatial Frequencies ◽  
Natural Difference ◽  
Subcortical Pathway

Humans have structures dedicated to the processing of faces, which include cortical components (e.g. areas in occipital and temporal lobes) and subcortical components (e.g. superior colliculus and amygdala). Although faces are processed more quickly than stimuli from other categories, there is a lack of consensus regarding whether cortical or subcortical structures are responsible for rapid face processing. In order to probe this, we exploited the asymmetry in the strength of projections to subcortical structures between the nasal and temporal hemiretina. Participants detected faces from unrecognizable control stimuli and performed the same task for houses. In Experiments 1 and 3, at the fastest reaction times, participants detected faces more accurately than houses. However, there was no benefit of presenting to the subcortical pathway. In Experiment 2, we probed the coarseness of the rapid pathway, making the foil stimuli more similar to faces and houses. This eliminated the rapid detection advantage, suggesting that rapid face processing is limited to coarse representations. In Experiment 4, we sought to determine whether the natural difference between spatial frequencies of faces and houses were driving the effects seen in Experiments 1 and 3. We spatially filtered the faces and houses so that they were matched. Better rapid detection was again found for faces relative to houses, but we found no benefit of preferentially presenting to the subcortical pathway. Taken together, the results of our experiments suggest a cortical, coarse rapid detection mechanism, which was not dependent on spatial frequency.

scholarly journals Rapid and coarse face detection: With a lack of evidence for a nasal-temporal asymmetry

2020 ◽  
Vol 82 (4) ◽  
pp. 1883-1895
Author(s):  
Laura Cabral ◽  
Bobby Stojanoski ◽  
Rhodri Cusack
Keyword(s):  
Face Processing ◽  
Rapid Detection ◽  
Reaction Times ◽  
Subcortical Structures ◽  
Detection Mechanism ◽  
Temporal Asymmetry ◽  
Temporal Lobes ◽  
Spatial Frequencies ◽  
Natural Difference ◽  
Subcortical Pathway

AbstractHumans have structures dedicated to the processing of faces, which include cortical components (e.g., areas in occipital and temporal lobes) and subcortical components (e.g., superior colliculus and amygdala). Although faces are processed more quickly than stimuli from other categories, there is a lack of consensus regarding whether subcortical structures are responsible for rapid face processing. In order to probe this, we exploited the asymmetry in the strength of projections to subcortical structures between the nasal and temporal hemiretina. Participants detected faces from unrecognizable control stimuli and performed the same task for houses. In Experiments 1 and 3, at the fastest reaction times, participants detected faces more accurately than houses. However, there was no benefit of presenting to the subcortical pathway. In Experiment 2, we probed the coarseness of the rapid pathway, making the foil stimuli more similar to faces and houses. This eliminated the rapid detection advantage, suggesting that rapid face processing is limited to coarse representations. In Experiment 4, we sought to determine whether the natural difference between spatial frequencies of faces and houses were driving the effects seen in Experiments 1 and 3. We spatially filtered the faces and houses so that they were matched. Better rapid detection was again found for faces relative to houses, but we found no benefit of preferentially presenting to the subcortical pathway. Taken together, the results of our experiments suggest a coarse rapid detection mechanism, which was not dependent on spatial frequency, with no advantage for presenting preferentially to subcortical structures.

Flicker Masking and Developmental Dyslexia

Perception ◽  
1986 ◽  
Vol 15 (4) ◽  
pp. 473-482 ◽  
Author(s):  
Andrew T Smith ◽  
Frances Early ◽  
Sarah C Grogan
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Developmental Dyslexia ◽  
Cell Function ◽  
Cell Activity ◽  
Reaction Times ◽  
Visual Persistence ◽  
Reading Impairment ◽  
Spatial Frequencies

Recent studies have provided evidence that dyslexic children tend to show longer visual persistence than control children when presented with low-spatial-frequency grating stimuli. The possibility that this phenomenon might reflect an impairment of inhibitory Y-cell activity in the visual system of dyslexics has been investigated. A flicker masking technique was used to mask Y-cell activity selectively in a group of dyslexic boys and a group of age-matched controls. There were no overall differences in reaction times to the offsets of grating patterns of various spatial frequencies between the groups, and no differences between subgroups defined by age, degree of reading impairment, or any other criterion. The results show no evidence of abnormal Y-cell function in developmental dyslexia.

Spatial Frequency Thresholds for Detecting Latent Facial Signals of Threat

Perception ◽  
2019 ◽  
Vol 48 (3) ◽  
pp. 214-227
Author(s):  
Nicholas Watier ◽  
Brock DeGagne
Keyword(s):  
Spatial Frequency ◽  
Face Processing ◽  
Visual Information ◽  
Forced Choice ◽  
Face Identification ◽  
Staircase Procedure ◽  
Spatial Frequencies

This study examined whether latent facial signals of threat can be detected at more extreme ranges of spatial frequencies (SFs), and thus with fewer frequencies from an optimal middle band for face identification, compared with latent nonthreatening facial signals. Using an adaptive staircase procedure and a two-interval forced-choice same-different task, SF thresholds from the lower and higher ends of the SF spectrum were obtained for nonexpressive threatening and nonthreatening faces. Threatening faces were discriminated from neutral faces more quickly and accurately, and engendered more extreme SF thresholds, compared with nonthreatening faces. The results indicate that the components of latent threatening facial signals can be detected under a greater degree of impoverished visual information for face processing compared with their nonthreatening counterparts.

scholarly journals Residual abilities in age-related macular degeneration to process spatial frequencies during natural scene categorization

2011 ◽  
Vol 28 (6) ◽  
pp. 529-541 ◽  
Author(s):  
BENOIT MUSEL ◽  
RUXANDRA HERA ◽  
SYLVIE CHOKRON ◽  
DAVID ALLEYSSON ◽  
CHRISTOPHE CHIQUET ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Macular Degeneration ◽  
Reaction Times ◽  
Age Related Macular Degeneration ◽  
Natural Scenes ◽  
Natural Scene ◽  
Scene Categorization ◽  
Age Related ◽  
Spatial Frequencies ◽  
Healthy Participants

AbstractAge-related macular degeneration (AMD) is characterized by a central vision loss. We explored the relationship between the retinal lesions in AMD patients and the processing of spatial frequencies in natural scene categorization. Since the lesion on the retina is central, we expected preservation of low spatial frequency (LSF) processing and the impairment of high spatial frequency (HSF) processing. We conducted two experiments that differed in the set of scene stimuli used and their exposure duration. Twelve AMD patients and 12 healthy age-matched participants in Experiment 1 and 10 different AMD patients and 10 healthy age-matched participants in Experiment 2 performed categorization tasks of natural scenes (Indoors vs. Outdoors) filtered in LSF and HSF. Experiment 1 revealed that AMD patients made more no-responses to categorize HSF than LSF scenes, irrespective of the scene category. In addition, AMD patients had longer reaction times to categorize HSF than LSF scenes only for indoors. Healthy participants’ performance was not differentially affected by spatial frequency content of the scenes. In Experiment 2, AMD patients demonstrated the same pattern of errors as in Experiment 1. Furthermore, AMD patients had longer reaction times to categorize HSF than LSF scenes, irrespective of the scene category. Again, spatial frequency processing was equivalent for healthy participants. The present findings point to a specific deficit in the processing of HSF information contained in photographs of natural scenes in AMD patients. The processing of LSF information is relatively preserved. Moreover, the fact that the deficit is more important when categorizing HSF indoors, may lead to new perspectives for rehabilitation procedures in AMD.

scholarly journals Emotion Recognition in Low-Spatial Frequencies Is Partly Preserved following Traumatic Brain Injury

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Alessia Celeghin ◽  
Valentina Galetto ◽  
Marco Tamietto ◽  
Marina Zettin
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Spatial Frequency ◽  
Emotion Recognition ◽  
Diffuse Axonal Injury ◽  
Reaction Times ◽  
Emotion Perception ◽  
High Spatial Frequency ◽  
Healthy Controls ◽  
Spatial Frequencies

After a Traumatic Brain Injury (TBI), emotion recognition is typically impaired. This is commonly attributed to widespread multifocal damage in cortical areas involved in emotion processing as well as to Diffuse Axonal Injury (DAI). However, current models suggest that emotional recognition is subserved by a distributed network cantered on the amygdala, which involves both cortical and subcortical structures. While the cortical system is preferentially tuned to process high spatial frequencies, the subcortical networks are more sensitive to low-spatial frequencies. The aim of this study was to evaluate whether emotion perception from low-spatial frequencies underpinning the subcortical system is relatively preserved in TBI patients. We tested a group of 14 subjects with severe TBI and 20 matched healthy controls. Each participant was asked to recognize the emotion expressed by each stimulus that consisted of happy and fearful faces, filtered for their low and high spatial frequencies components. Results in TBI patients’ performances showed that low-spatial frequency expressions were recognized with higher accuracy and faster reaction times when compared to high spatial frequency stimuli. On the contrary, healthy controls did not show any effect in the two conditions, neither for response accuracy nor for reaction times. The outcomes of this study indicate that emotion perception from low-spatial frequencies is relatively preserved in TBI, thereby suggesting spare of functioning in the subcortical system in mediating emotion recognition.

Global Precedence, Spatial Frequency Channels, and the Statistics of Natural Images

1996 ◽  
Vol 8 (3) ◽  
pp. 197-230 ◽  
Author(s):  
Howard C. Hughes ◽  
George Nozawa ◽  
Frederick Kitterle
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Reaction Times ◽  
Low Frequency ◽  
Natural Images ◽  
Visual Pattern ◽  
Pattern Perception ◽  
Global Precedence ◽  
Processing Times ◽  
Spatial Frequencies

A great deal of evidence suggests that early in processing, retinal images are filtered by parallel, spatial frequency selective channels. We attempt to incorporate this view of early vision with the principle of global precedence, which holds that Gestalt-like processes sensitive to global image configurations tend to dominate local feature processing in human pattern perception. Global precedence is inferred from the pattern of reaction times observed when visual patterns contain multiple cues at different levels of spatial scale. Specifically, it is frequently observed that global processing times are largely unaffected by conflicting local cues, but local processing times are substantially lengthened by conflicting global cues. The asymmetry of these effects suggests the dominant role of global configurations. Since global spatial information is effectively represented by low spatial frequencies, global precedence potentially implies a low frequency dominance. The thesis is that low spatial frequencies tend to be available before information carried by higher frequency bands, producing a coarse-to-fine temporal order in visual spatial perception. It is suggested that a variety of factors contribute to the “prior entry” of low frequency information, including the high contrast gain of the magnocellular pathway, the amplitude spectra typical of natural images, and inhibitory interactions between the parallel frequency-tuned channels. Evidence suggesting a close relationship between global precedence and spatial frequency channels is provided by observations that the essential features of the global precedence effect are obtained using patterns consisting of low and high frequency sinusoids. The hypothesis that these asymmetric interference effects are due to interactions between parallel spatial channels is supported by an analysis of reaction times (RTs), which shows that RTs to redundant low and high frequency cues produce less facilitation than predictions that assume the channels are independent. In view of previous work showing that global precedence depends upon the low frequency content of the stimuli, we suggest that low spatial frequencies represent the sine qua non for the dominance of configurational cues in human pattern perception, and that this configurational dominance reflects the microgenesis of visual pattern perception. This general view of the temporal dynamics of visual pattern recognition is discussed, is considered from an evolutionary perspective, and is related to certain statistical regularities in natural scenes. Potential adaptive advantages of an interactive parallel architecture that confers an initial processing advantage to low resolution information are explored.

scholarly journals A Rapid Subcortical Amygdala Route for Faces Irrespective of Spatial Frequency and Emotion

2016 ◽  
Author(s):  
Jessica McFadyen ◽  
Martial Mermillod ◽  
Jason B. Mattingley ◽  
Veronika Halász ◽  
Marta I. Garrido
Keyword(s):  
Neural Network ◽  
Spatial Frequency ◽  
Neural Activity ◽  
Visual Pathway ◽  
Data Driven ◽  
Causal Modelling ◽  
Fearful Faces ◽  
Spatial Frequencies ◽  
Amygdala Activity ◽  
Subcortical Pathway

ABSTRACTThere is significant controversy over the anatomical existence and potential function of a direct subcortical visual pathway to the amygdala. It is thought that this pathway rapidly transmits low spatial frequency information to the amygdala independently of the cortex and yet this function has never been causally determined. In this study, neural activity was measured using magnetoencephalography (MEG) while participants discriminated the gender of neutral and fearful faces filtered for low or high spatial frequencies. Dynamic causal modelling (DCM) revealed that the most likely underlying neural network consisted of a subcortical pulvino-amygdala connection that was not modulated by spatial frequency or emotion and a cortico-amygdala connection that conveyed predominantly high spatial frequencies. Crucially, data-driven neural simulations demonstrated a clear temporal advantage of the subcortical route (70ms) over the cortical route (155ms) in influencing amygdala activity. Thus, our findings support the existence of a rapid functional subcortical pathway that is unselective of the spatial frequency or emotional content of faces.

The Perceived Duration of Gratings

Perception ◽  
1992 ◽  
Vol 21 (2) ◽  
pp. 161-166 ◽  
Author(s):  
John A Baro ◽  
Lynda J Brzezicki ◽  
Stephen Lehmkuhle ◽  
Howard C Hughes
Keyword(s):  
Spatial Frequency ◽  
Reaction Times ◽  
Visible Persistence ◽  
Subjective Duration ◽  
Spatial Frequencies ◽  
The Difference ◽  
Perceived Duration

Since visible persistence of grating patterns increases with spatial frequency, it is often inferred that the perceived duration of a grating is also longer at higher spatial frequencies. However, other work has demonstrated that the perceived onset of a grating is also delayed at higher spatial frequencies. Thus it is impossible to infer the subjective duration from the results of visible persistence studies alone. In order to estimate perceived duration in the present study, reaction times (RTs) to grating onsets and offsets were measured for a range of spatial frequencies. The results indicate that although the perceived duration (ie the difference between offset and onset RTs) was consistently longer than the physical duration, the estimates of perceived duration did not vary with changes in spatial frequency. Differences between the present results and earlier findings are interpreted in the context of the different methods used to measure perceived offset.

Visual reaction time of cats to different spatial frequencies

1990 ◽  
Vol 5 (6) ◽  
pp. 557-564 ◽  
Author(s):  
Bonnie E. Aiken ◽  
Michael S. Loop
Keyword(s):  
Reaction Time ◽  
Spatial Frequency ◽  
Reaction Times ◽  
Sine Wave ◽  
Contrast Threshold ◽  
Visual Reaction Time ◽  
Spatial Frequencies ◽  
Visual Reaction ◽  
X Cells ◽  
Y Cells

AbstractIf physiological mechanisms similar to cat Y and X cells explain faster detection of low spatial frequencies by humans, then cats should show the same effect. We have tested this prediction by determining the visual reaction time of cats over a range of spatial frequencies and contrasts by training them to respond quickly when a vertical sine-wave grating was presented. At 50% contrast, the cat's visual reaction time increased monotonically from 0.25–2.0 cpd (cycle/deg). At every spatial frequency tested, the cat's reaction time increased monotonically as contrast decreased. By determining contrast threshold (70% detection) at each spatial frequency, it was possible to determine reaction times for different spatial frequencies at equal physical contrasts and equal “threshold equivalent” contrasts. Some of the cat's faster detection of low spatial frequencies was due to sensitivity differences and some was not. To determine if faster detection of low spatial frequencies was based upon Y cells, we took advantage of the fact that Y cells show a strong peripheral effect while X cells do not. Low and high spatial frequencies were detected in the presence of a flickering (7 Hz) or steady (70 Hz) surround. Surround frequency had no effect upon reaction times to 2.0 cpd but the flickering surround increased reaction times to 0.25 cpd. These results indicate that, in cats, rapid detection of low spatial frequencies is by Y cells and slower detection of high spatial frequencies is by X cells.

scholarly journals Numerical Simulation on Spatial-Frequency Domain Imaging for Estimating Optical Absorption and Scattering Properties of Two-Layered Horticultural Products

2021 ◽  
Vol 11 (2) ◽  
pp. 617
Author(s):  
Dong Hu ◽  
Yuping Huang ◽  
Qiang Zhang ◽  
Lijian Yao ◽  
Zidong Yang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Property ◽  
Optical Absorption ◽  
Spatial Frequency ◽  
Estimation Accuracy ◽  
Property Estimation ◽  
Spatial Frequencies ◽  
Stepwise Method ◽  
Horticultural Products ◽  
Layered Samples

Spatial-frequency domain imaging (SFDI) is a wide-field, noncontact, and label-free imaging modality that is currently being explored as a new means for estimating optical absorption and scattering properties of two-layered turbid materials. The accuracy of SFDI for optical property estimation, however, depends on light transfer model and inverse algorithm. This study was therefore aimed at providing theoretical analyses of the diffusion model and inverse algorithm through numerical simulation, so as to evaluate the potential for estimating optical absorption and reduced scattering coefficients of two-layered horticultural products. The effect of varying optical properties on reflectance prediction was first simulated, which indicated that there is good separation in diffuse reflectance over a large range of spatial frequencies for different reduced scattering values in the top layer, whereas there is less separation in diffuse reflectance for different values of absorption in the top layer, and even less separation for optical properties in the bottom layer. To implement the nonlinear least-square method for extracting the optical properties of two-layered samples from Monte Carlo-generated reflectance, five curve fitting strategies with different constrained parameters were conducted and compared. The results confirmed that estimation accuracy improved as fewer variables were to be estimated each time. A stepwise method was thus suggested for estimating optical properties of two-layered samples. Four factors influencing optical property estimation of the top layer, which is the basis for accurately implementing the stepwise method, were investigated by generating absolute error contour maps. Finally, the relationship between light penetration depth and spatial frequency was studied. The results showed that penetration depth decreased with the increased spatial frequency and also optical properties, suggesting that appropriate selection of spatial frequencies for a stepwise method to estimate optical properties from two-layered samples provides potential for estimation accuracy improvement. This work lays a foundation for improving optical property estimation of two-layered horticultural products using SFDI.

Sign in / Sign up

Export Citation Format

Share Document