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Journal articles on the topic 'Visual Discrimination Task'

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Published: 10 December 2022
Last updated: 29 January 2023

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1

Gaillard, B., and J. Feng. "Modelling a visual discrimination task." Neurocomputing 65-66 (June 2005): 203–9. http://dx.doi.org/10.1016/j.neucom.2004.10.008.

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2

Huk, Alexander C., and David J. Heeger. "Task-Related Modulation of Visual Cortex." Journal of Neurophysiology 83, no. 6 (June 1, 2000): 3525–36. http://dx.doi.org/10.1152/jn.2000.83.6.3525.

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We performed a series of experiments to quantify the effects of task performance on cortical activity in early visual areas. Functional magnetic resonance imaging (fMRI) was used to measure cortical activity in several cortical visual areas including primary visual cortex (V1) and the MT complex (MT+) as subjects performed a variety of threshold-level visual psychophysical tasks. Performing speed, direction, and contrast discrimination tasks produced strong modulations of cortical activity. For example, one experiment tested for selective modulations of MT+ activity as subjects alternated between performing contrast and speed discrimination tasks. MT+ responses modulated in phase with the periods of time during which subjects performed the speed discrimination task; that is, MT+ activity was higher during speed discrimination than during contrast discrimination. Task-related modulations were consistent across repeated measurements in each subject; however, significant individual differences were observed between subjects. Together, the results suggest 1) that specific changes in the cognitive/behavioral state of a subject can exert selective and reliable modulations of cortical activity in early visual cortex, even in V1; 2) that there are significant individual differences in these modulations; and 3) that visual areas and pathways that are highly sensitive to small changes in a given stimulus feature (such as contrast or speed) are selectively modulated during discrimination judgments on that feature. Increasing the gain of the relevant neuronal signals in this way may improve their signal-to-noise to help optimize task performance.
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3

Fukuda, Kyosuke. "Analysis of Eyeblink Activity during Discriminative Tasks." Perceptual and Motor Skills 79, no. 3_suppl (December 1994): 1599–608. http://dx.doi.org/10.2466/pms.1994.79.3f.1599.

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To evaluate the blinking pattern during and after cognitive processing, 10 subjects' eyeblinks were recorded by a videotape recording camera placed 100 cm from the subjects' side. The subjects' task was to discriminate two kinds of auditory tones presented serially and to discriminate two kinds of visual stimuli presented serially. Treatments were composed of the baseline condition preexperiment, the visual task with no discrimination, the visual discriminative task, the auditory task with no discrimination, and the auditory discriminative task. The blink rate in each treatment, the temporal distribution of blinks poststimulus, and the blink waveform were evaluated. Although blinks were not inhibited during tasks, frequent blinks after tasks were observed in both modalities. Blinks concentrated between 300 msec. and 800 msec. after the discriminated stimulus and formulated the blink-rate peak. The closing velocity of lid in the blink rate peak was lower after auditory stimulus. Moreover, the lid's opening velocity after the auditory discrimination was higher. These results indicated that the eyelid closed slowly and opened quickly after the auditory discriminative stimulus.
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4

Jaén, EM, EM Colombo, and CF Kirschbaum. "A simple visual task to assess flicker effects on visual performance." Lighting Research & Technology 43, no. 4 (July 11, 2011): 457–71. http://dx.doi.org/10.1177/1477153511405409.

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Temporal modulation of lighting at frequencies higher than the critical fusion frequency can affect human efficiency in diverse ways that are not understood. A simple visual search task was used to assess visual performance under lighting with low (3%) and high (32%) temporal modulation and compared with the results of a conventional discrimination task in an identical situation. Even when side-by-side subjective appraisal corroborates that there are no visually perceptible differences between the two forms of lighting, both tasks show a reduction in visual performance when temporal modulation increases. Significantly larger relative differences between the two levels of modulation and better discrimination between individuals were obtained with the visual search task, demonstrating that the search task could be more useful for identifying individuals sensitive to flicker. The reasons why the visual search task might be more sensitive to flicker than the discrimination task are discussed.
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5

Seider, T., E. Porges, A. Woods, and R. Cohen. "C-19 An fMRI Study of Age-Associated Changes in Basic Visual Discrimination." Archives of Clinical Neuropsychology 34, no. 6 (July 25, 2019): 1048. http://dx.doi.org/10.1093/arclin/acz034.181.

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Abstract Objective The study was conducted to determine age-associated changes in functional brain response, measured with fMRI, during visual discrimination with regard to three elementary components of visual perception: shape, location, and velocity. A secondary aim was to validate the method used to isolate the hypothesized brain regions associated with these perceptual functions. Method Items from the Visual Assessment Battery (VAB), a simultaneous match-to-sample task, assessed visual discrimination in 40 healthy adults during fMRI. Participants were aged 51-91 and recruited from a larger community sample for a study on normal aging. The tasks were designed to isolate neural recruitment during discrimination of either location, shape, or velocity by using tasks that were identical aside from the perceptual skill required to complete them. Results The Location task uniquely activated the dorsal visual processing stream, the Shape task the ventral stream, and the Velocity task V5/MT. Greater age was associated with greater neural recruitment, particularly in frontal areas (uncorrected voxel-level p < .001, family-wise error cluster-level p□.05). Conclusions Results validated the specialization of brain regions for spatial, perceptual, and movement discriminations and the use of the VAB to assess functioning localized to these regions. Anterior neural recruitment during visual discrimination increases with age.
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6

Merigan, William H. "Basic visual capacities and shape discrimination after lesions of extrastriate area V4 in macaques." Visual Neuroscience 13, no. 1 (January 1996): 51–60. http://dx.doi.org/10.1017/s0952523800007124.

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Abstractlbotenic acid lesions were made in four macaque monkeys in a region of cortical area V4 that corresponds to the lower quadrant of one hemifield. For visual testing, fixation locus was monitoredwith scleral search coils and controlled behaviorally to place test stimuli either in the lesionedquadrant or in a control location in the opposite hemifield. Some basic visual capacities were slightly altered by the lesions; there was a two-fold reduction of luminance contrast sensitivity as well as red-green chromatic contrast sensitivity, both tested with stationary gratings. On the other hand, little or no loss was found when contrast sensitivity for detection or direction discrimination was tested with 10–Hz drifting gratings nor was there a reliable change in visual acuity. Hue and luminance matching were tested with a spatially more complex matching-to-sample task, but monkeys could not learn this task in the visual field locus of a V4 lesion. If previously trained at this locus, performance was not affected by the lesion. In contrast to the small effects on basic visual capabilities, performance on two form discrimination tasks was devastated by V4 lesions. The first involved discriminating the orientation of colinear groups of dots on a background of randomly placed dots. The second involved discriminating the orientation of a group of three line segments surrounded by differently oriented line segments. Some selectivity of the deficitsfor form discrimination was shown by the lack of an effect of the lesions on a global motion discrimination. These results show that while V4 lesions cause only slight disruptions of basic visual capacities, they profoundly disrupt form discriminations.
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7

Richmond, B. J., and T. Sato. "Enhancement of inferior temporal neurons during visual discrimination." Journal of Neurophysiology 58, no. 6 (December 1, 1987): 1292–306. http://dx.doi.org/10.1152/jn.1987.58.6.1292.

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1. Previous results have shown that spatially directed attention enhances the stimulus-elicited responses of neurons in some areas of the brain. In the inferior temporal (IT) cortex, however, directing attention toward a stimulus mildly inhibits the responses of the neurons. Inferior temporal cortex is involved in pattern discrimination, but not spatial localization. If enhancement signifies that a neuron is participating in the function for which that part of cortex is responsible, then pattern discrimination, not spatial attention, should enhance responses of IT neurons. The influence of pattern discrimination behavior on the responses of IT neurons was therefore compared with previously reported suppressive influences of both spatial attention and the fixation point. 2. Single IT neurons were recorded from two monkeys while they performed each of five tasks. One task required the monkey to make a pattern discrimination between a bar and a square of light. In the other four tasks the same bar of light appeared, but the focus of spatial attention could differ, and the fixation point could be present or absent. Either attention to (without discrimination of) the bar stimulus or the presence of the fixation point attenuated responses slightly. These two suppressive influences produced a greater attenuation when both were present. 3. The visual conditions and motor requirements when the bar stimulus appeared in the discrimination task were identical to those of the trials in the stimulus attention task. However, one-half of the responsive neurons showed significantly stronger responses to the bar stimulus when it appeared in the discrimination task than when it appeared in the stimulus attention task. For most of these neurons, discrimination just overcame the combined effect of the two suppressive influences. For six other neurons, the response strength was significantly greater during the discrimination task than during any other task. 4. The monkeys achieved an overall correct performance rate of 90% in both the discrimination and stimulus attention tasks. To achieve this performance in the discrimination task they adopted a strategy in which they performed one trial type, bar stimulus attention trials, perfectly (100%) and the other trial type, pattern trials, relatively poorly (84% correct).(ABSTRACT TRUNCATED AT 400 WORDS)
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8

Jazayeri, M., and J. A. Movshon. "Visual motion processing in a direction discrimination task." Journal of Vision 5, no. 8 (March 16, 2010): 494. http://dx.doi.org/10.1167/5.8.494.

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9

Rahmouni, Sohir, Anna Montagnini, and Laurent Madelain. "Saccadic gain controlled by a visual discrimination task." Journal of Vision 17, no. 10 (August 31, 2017): 899. http://dx.doi.org/10.1167/17.10.899.

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10

Suge, Rie, Hajime Hasegawa, and Tomokazu Shimazu. "Learning deficit of OLETF in visual discrimination task." Neuroscience Research 58 (January 2007): S226. http://dx.doi.org/10.1016/j.neures.2007.06.499.

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11

Freunberger, Roman, Wolfgang Klimesch, Paul Sauseng, Birgit Griesmayr, Yvonne Höller, Thomas Pecherstorfer, and Simon Hanslmayr. "Gamma oscillatory activity in a visual discrimination task." Brain Research Bulletin 71, no. 6 (March 2007): 593–600. http://dx.doi.org/10.1016/j.brainresbull.2006.11.014.

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12

Hopf, Jens-Max, Edward Vogel, Geoffrey Woodman, Hans-Jochen Heinze, and Steven J. Luck. "Localizing Visual Discrimination Processes in Time and Space." Journal of Neurophysiology 88, no. 4 (October 1, 2002): 2088–95. http://dx.doi.org/10.1152/jn.2002.88.4.2088.

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Previous studies of visual processing in humans using event-related potentials (ERPs) have demonstrated that task-related modulations of an early component called the “N1” wave (140–200 ms) reflect the operation of a voluntary discrimination process. Specifically, this component is larger in tasks requiring target discrimination than in tasks requiring simple detection. The present study was designed to localize this discriminative process in both time and space by means of combined magnetoencephalographic (MEG) and ERP recordings. Discriminative processing led to differential ERP and MEG activity beginning within 150 ms of stimulus onset. Source localization of the combined ERP/MEG data was performed using anatomical constraints from structural magnetic resonance images. These analyses revealed highly reliable and focused activity in regions of inferior occipital-temporal cortex. These findings indicate that the earliest measurable correlates of discriminative operations in the visual system appear as neural activity in circumscribed regions of the ventral processing stream.
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13

Lambert, Anthony, and Jane Holmes. "Ageing and Visual Orienting in Response to Complex Spatial Cues." Brain Impairment 5, no. 2 (December 1, 2004): 117–25. http://dx.doi.org/10.1375/brim.5.2.117.58255.

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AbstractAn experiment is reported in which young and older adults performed a visual orienting task and a cue discrimination task. In the visual orienting task symbolic cues (letters) provided predictive information concerning the likely location of a target stimulus. Two letters, drawn from a pool of four ‘valid’ and four ‘invalid’ letters, were presented bilaterally, at either central or peripheral locations. In the cue discrimination task participants were presented with the same bilateral letter stimuli, and indicated whether these represented a valid letter on the right with an invalid letter on the left, or vice versa. In the visual orienting task young adults shifted attention appropriately in response to the letter cues, but older adults failed to do this. Older participants also performed more poorly on the cue discrimination task. However, even older participants who performed as well as young participants on the cue discrimination task failed to orient in response to the letter cues. Results are discussed in terms of effects of ageing on the ability to forge functionally effective links between different task components in the course of learning how to perform new perceptuomotor skills.
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Adab, Hamed Zivari, Ivo D. Popivanov, Wim Vanduffel, and Rufin Vogels. "Perceptual Learning of Simple Stimuli Modifies Stimulus Representations in Posterior Inferior Temporal Cortex." Journal of Cognitive Neuroscience 26, no. 10 (October 2014): 2187–200. http://dx.doi.org/10.1162/jocn_a_00641.

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Practicing simple visual detection and discrimination tasks improves performance, a signature of adult brain plasticity. The neural mechanisms that underlie these changes in performance are still unclear. Previously, we reported that practice in discriminating the orientation of noisy gratings (coarse orientation discrimination) increased the ability of single neurons in the early visual area V4 to discriminate the trained stimuli. Here, we ask whether practice in this task also changes the stimulus tuning properties of later visual cortical areas, despite the use of simple grating stimuli. To identify candidate areas, we used fMRI to map activations to noisy gratings in trained rhesus monkeys, revealing a region in the posterior inferior temporal (PIT) cortex. Subsequent single unit recordings in PIT showed that the degree of orientation selectivity was similar to that of area V4 and that the PIT neurons discriminated the trained orientations better than the untrained orientations. Unlike in previous single unit studies of perceptual learning in early visual cortex, more PIT neurons preferred trained compared with untrained orientations. The effects of training on the responses to the grating stimuli were also present when the animals were performing a difficult orthogonal task in which the grating stimuli were task-irrelevant, suggesting that the training effect does not need attention to be expressed. The PIT neurons could support orientation discrimination at low signal-to-noise levels. These findings suggest that extensive practice in discriminating simple grating stimuli not only affects early visual cortex but also changes the stimulus tuning of a late visual cortical area.
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15

Yonekawa, Harue, Shingo Takagi, Kiyoyuki Yamazaki, and Katsuro Okamoto. "Effect of stimulus intensity on visual discrimination task performance." Japanese journal of ergonomics 33, Supplement (1997): 374–75. http://dx.doi.org/10.5100/jje.33.supplement_374.

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16

McCormick, D., and P. Mamassian. "Audio-visual synchrony in an Apparent-motion discrimination task." Journal of Vision 7, no. 9 (March 30, 2010): 871. http://dx.doi.org/10.1167/7.9.871.

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17

Walton, Mark, and Charles Spence. "Cross-modal congruency and visual capture in a visual elevation-discrimination task." Experimental Brain Research 154, no. 1 (January 1, 2004): 113–20. http://dx.doi.org/10.1007/s00221-003-1706-z.

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18

Kattner, Florian, and Christina B. Reimer. "Dissociating central and auditory attention: Is there a shared bottleneck for response selection and auditory search?" Quarterly Journal of Experimental Psychology 73, no. 10 (June 15, 2020): 1564–74. http://dx.doi.org/10.1177/1747021820928030.

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Central and auditory attention are limited in capacity. In dual-tasks, central attention is required to select the appropriate response, but because central attention is limited in capacity, response selection can only be carried out for one task at a time. In auditory search tasks, search time to detect the target sound increases with the number of distractor sounds added to the auditory scene (set sizes), indicating that auditory attention is limited in capacity. Here, we investigated whether central and auditory attention relied on common or distinct capacity limitations using a dual-task paradigm. In two experiments, participants completed a visual choice discrimination task (task 1) together with an auditory search task (task 2), and the two tasks were separated by an experimentally modulated stimulus onset asynchrony (SOA). Analysing auditory search time as a function of SOA and set sizes (locus-of-slack method) revealed that the auditory search process in task 2 was performed after response selection in a visual two-choice discrimination task 1 (Experiment 1), but concurrently with response selection in a visual four-choice discrimination task 1 (Experiment 2). Hence, although response selection in the visual four-choice discrimination task demanded more central attention as compared with response selection in the two-choice discrimination task, the auditory search process was performed in parallel. Distribution analyses of inter-response time further indicated that parallel processing of response selection and auditory search was not influenced by response grouping. Taken together, the two experiments provided evidence that central and auditory attention relied on distinct capacity limitations.
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Roberts, Daniel M., John R. Fedota, George A. Buzzell, Raja Parasuraman, and Craig G. McDonald. "Prestimulus Oscillations in the Alpha Band of the EEG Are Modulated by the Difficulty of Feature Discrimination and Predict Activation of a Sensory Discrimination Process." Journal of Cognitive Neuroscience 26, no. 8 (August 2014): 1615–28. http://dx.doi.org/10.1162/jocn_a_00569.

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Recent work has demonstrated that the occipital–temporal N1 component of the ERP is sensitive to the difficulty of visual discrimination, in a manner that cannot be explained by simple differences in low-level visual features, arousal, or time on task. These observations provide evidence that the occipital–temporal N1 component is modulated by the application of top–down control. However, the timing of this control process remains unclear. Previous work has demonstrated proactive, top–down modulation of cortical excitability for cued spatial attention or feature selection tasks. Here, the possibility that a similar top–down process facilitates performance of a difficult stimulus discrimination task is explored. Participants performed an oddball task at two levels of discrimination difficulty, with difficulty manipulated by modulating the similarity between target and nontarget stimuli. Discrimination processes and cortical excitability were assessed via the amplitude of the occipital–temporal N1 component and prestimulus alpha oscillation of the EEG, respectively. For correct discriminations, prestimulus alpha power was reduced, and the occipital–temporal N1 was enhanced in the hard relative to the easy condition. Furthermore, within the hard condition, prestimulus alpha power was reduced, and the occipital–temporal N1 was enhanced for correct relative to incorrect discriminations. The generation of ERPs contingent on relative prestimulus alpha power additionally suggests that diminished alpha power preceding stimulus onset is related to enhancement of the occipital–temporal N1. As in spatial attention, proactive control appears to enhance cortical excitability and facilitate discrimination performance in tasks requiring nonspatial, feature-based attention, even in the absence of competing stimulus features.
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Thaler, Lore, Megan Cutts, Denise Foresteire, Alison Wilkinson, and Charlotte Atkin. "Task irrelevant visual input reduces accuracy of echolocation in a size discrimination task." Journal of Vision 16, no. 12 (September 1, 2016): 145. http://dx.doi.org/10.1167/16.12.145.

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Horwitz, Gregory D., and William T. Newsome. "Target Selection for Saccadic Eye Movements: Direction-Selective Visual Responses in the Superior Colliculus." Journal of Neurophysiology 86, no. 5 (November 1, 2001): 2527–42. http://dx.doi.org/10.1152/jn.2001.86.5.2527.

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We investigated the role of the superior colliculus (SC) in saccade target selection in rhesus monkeys who were trained to perform a direction-discrimination task. In this task, the monkey discriminated between opposed directions of visual motion and indicated its judgment by making a saccadic eye movement to one of two visual targets that were spatially aligned with the two possible directions of motion in the display. Thus the neural circuits that implement target selection in this task are likely to receive directionally selective visual inputs and be closely linked to the saccadic system. We therefore studied prelude neurons in the intermediate and deep layers of the SC that can discharge up to several seconds before an impending saccade, indicating a relatively high-level role in saccade planning. We used the direction-discrimination task to identify neurons whose prelude activity “predicted” the impending perceptual report several seconds before the animal actually executed the operant eye movement; these “choice predicting” cells comprised ∼30% of the neurons we encountered in the intermediate and deep layers of the SC. Surprisingly, about half of these prelude cells yielded direction-selective responses to our motion stimulus during a passive fixation task. In general, these neurons responded to motion stimuli in many locations around the visual field including the center of gaze where the visual discriminanda were positioned during the direction-discrimination task. Preferred directions generally pointed toward the location of the movement field of the SC neuron in accordance with the sensorimotor demands of the discrimination task. Control experiments indicate that the directional responses do not simply reflect covertly planned saccades. Our results indicate that a small population of SC prelude neurons exhibits properties appropriate for linking stimulus cues to saccade target selection in the context of a visual discrimination task.
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Ragonese, Giulia, Paolo Baragli, Chiara Mariti, Angelo Gazzano, Antonio Lanatà, Adriana Ferlazzo, Esterina Fazio, and Cristina Cravana. "Interspecific two-dimensional visual discrimination of faces in horses (Equus caballus)." PLOS ONE 16, no. 2 (February 19, 2021): e0247310. http://dx.doi.org/10.1371/journal.pone.0247310.

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In social animals, recognizing conspecifics and distinguishing them from other animal species is certainly important. We hypothesize, as demonstrated in other species of ungulates, that horses are able to discriminate between the faces of conspecifics and the faces of other domestic species (cattle, sheep, donkeys and pigs). Our hypothesis was tested by studying inter-and intra-specific visual discrimination abilities in horses through a two-way instrumental conditioning task (discrimination and reversal learning), using two-dimensional images of faces as discriminative stimuli and food as a positive reward. Our results indicate that 8 out of 10 horses were able to distinguish between two-dimensional images of the faces of horses and images showing the faces of other species. A similar performance was obtained in the reversal task. The horses’ ability to learn by discrimination is therefore comparable to other ungulates. Horses also showed the ability to learn a reversal task. However, these results were obtained regardless of the images the tested horses were exposed to. We therefore conclude that horses can discriminate between two dimensional images of conspecifics and two dimensional images of different species, however in our study, they were not able to make further subcategories within each of the two categories. Despite the fact that two dimensional images of animals could be treated differently from two dimensional images of non-social stimuli, our results beg the question as to whether a two-dimensional image can replace the real animal in cognitive tests.
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Ostendorf, Florian, Carsten Finke, and Christoph J. Ploner. "Inhibition of Visual Discrimination During a Memory-Guided Saccade Task." Journal of Neurophysiology 92, no. 1 (July 2004): 660–64. http://dx.doi.org/10.1152/jn.01045.2003.

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Voluntary behavior critically depends on attentional selection and short-term maintenance of perceptual information. Recent research suggests a tight coupling of both cognitive functions with visual processing being selectively enhanced by working memory representations. Here, we combined a memory-guided saccade paradigm (6-s delay) with a visual discrimination task, performed either 1,500, 2,500, or 3,500 ms after presentation of the memory cue. Contrary to what can be expected from previous studies, our results show that memory of spatial cues can transiently delay speeded discrimination of stimuli presented at remembered locations. This effect was not observed in a control experiment without memory requirements. Furthermore, delayed discrimination was dependent on the strength of actual memory representations as reflected by accuracy of memory-guided saccades. We propose an active inhibitory mechanism that counteracts facilitating effects of spatial working memory, promoting flexible orienting to novel information during maintenance of spatial memoranda for intended actions. Inhibitory delay-period activity in prefrontal cortex is a likely source for this mechanism which may be mediated by prefronto-tectal projections.
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Lauwereyns, Johan, Masamichi Sakagami, Ken-Ichiro Tsutsui, Shunsuke Kobayashi, Masashi Koizumi, and Okihide Hikosaka. "Responses to Task-Irrelevant Visual Features by Primate Prefrontal Neurons." Journal of Neurophysiology 86, no. 4 (October 1, 2001): 2001–10. http://dx.doi.org/10.1152/jn.2001.86.4.2001.

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The primate brain is equipped with prefrontal circuits for interpreting visual information, but how these circuits deal with competing stimulus-response (S-R) associations remains unknown. Here we show different types of responses to task-irrelevant visual features in three functionally dissociated groups of primate prefrontal neurons. Two Japanese macaques participated in a go/no-go task in which they had to discriminate either the color or the motion direction of a visual target to make a correct manual response. Prior to the experiment, the monkeys had been trained extensively so that they acquired fixed associations between visual features and required responses (e.g., “green = go”; “downward motion = no-go”). In this design, the monkey was confronted with a visual target from which it had to extract relevant information (e.g., color in the color-discrimination condition) while ignoring irrelevant information (e.g., motion direction in the color-discrimination condition). We recorded from 436 task-related prefrontal neurons while the monkey performed the multidimensional go/no-go task: 139 (32%) neurons showed go/no-go discrimination based on color as well as motion direction (“integration cells”); 192 neurons (44%) showed go/no-go discrimination only based on color (“color-feature cells”); and 105 neurons (24%) showed go/no-go discrimination only based on motion direction (“motion-feature cells”). Overall, however, 162 neurons (37%) were influenced by irrelevant information: 53 neurons (38%) among integration cells, 71 neurons (37%) among color-feature cells, and 38 neurons (36%) among motion-feature cells. Across all types of neurons, the response to an irrelevant feature was positively correlated with the response to the same feature when it was relevant, indicating that the influence from irrelevant information is a residual from S-R associations that are relevant in a different context. Temporal and anatomical differences among integration, color-feature and motion-feature cells suggested a sequential mode of information processing in prefrontal cortex, with integration cells situated toward the output of the decision-making process. In these cells, the response to irrelevant information appears as a congruency effect, with better go/no-go discrimination when both the relevant and irrelevant feature are associated with the same response than when they are associated with different responses. This congruency effect could be the result of the combined input from color- and motion-feature cells. Thus these data suggest that irrelevant features lead to partial activation of neurons even toward the output of the decision-making process in primate prefrontal cortex.
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Perrott, David R., Brian Costantino, and John Cisneros. "Auditory and visual localization performance in a sequential discrimination task." Journal of the Acoustical Society of America 93, no. 4 (April 1993): 2134–38. http://dx.doi.org/10.1121/1.406675.

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26

Trick, Lana M., James T. Enns, and Darlene A. Brodeur. "Life span changes in visual enumeration: The number discrimination task." Developmental Psychology 32, no. 5 (1996): 925–32. http://dx.doi.org/10.1037/0012-1649.32.5.925.

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27

Deyo, Richard A., Jaak Panksepp, and Robert L. Conner. "Nimodipine alters acquisition of a visual discrimination task in chicks." Behavioral and Neural Biology 53, no. 2 (March 1990): 149–52. http://dx.doi.org/10.1016/0163-1047(90)90339-8.

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Deyo, Richard A., Dorothy A. Nix, and T. W. Parker. "Nifedipine blocks retention of a visual discrimination task in chicks." Behavioral and Neural Biology 57, no. 3 (May 1992): 260–62. http://dx.doi.org/10.1016/0163-1047(92)90262-3.

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29

Dupont, P., G. A. Orban, R. Vogels, G. Bormans, J. Nuyts, C. Schiepers, M. De Roo, and L. Mortelmans. "Different perceptual tasks performed with the same visual stimulus attribute activate different regions of the human brain: a positron emission tomography study." Proceedings of the National Academy of Sciences 90, no. 23 (December 1, 1993): 10927–31. http://dx.doi.org/10.1073/pnas.90.23.10927.

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To investigate the processing of visual form in human cerebral cortex, we used the PET (positron emission tomography) activation technique to compare the human brain regions that are involved in a visual detection task and two orientation discrimination tasks: the temporal same-different (TSD) task, which includes a short-term memory component, and the identification (ID) task, which is without this component. As a control task we used passive viewing. Stimuli were identical in all four tasks. Subtraction of passive viewing from detection showed that the detection task activates early visual cortical regions (areas 17/18) as well as several motor brain regions, while decreasing activity in several higher order frontal, temporal, and parietal regions. Comparing the ID task to the detection task revealed no further visual cortical activation, while comparison of the TSD task to the detection task revealed an activation of several right visual cortical regions, one of which remained significant after the subtraction of ID from TSD (right area 19). These experiments demonstrate the task dependence of visual processing, even for very closely related tasks, and the localization of the temporal comparison component involved in orientation discrimination in human area 19.
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Penney, Trevor B., Xiaoqin Cheng, Yan Ling Leow, Audrey Wei Ying Bay, Esther Wu, Sophie K. Herbst, and Shih Cheng Yen. "Saccades and Subjective Time in Seconds Range Duration Reproduction." Timing & Time Perception 4, no. 2 (June 10, 2016): 187–206. http://dx.doi.org/10.1163/22134468-00002066.

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A transient suppression of visual perception during saccades ensures perceptual stability. In two experiments, we examined whether saccades affect time perception of visual and auditory stimuli in the seconds range. Specifically, participants completed a duration reproduction task in which they memorized the duration of a 6 s timing signal during the training phase and later reproduced that duration during the test phase. Four experimental conditions differed in saccade requirements and the presence or absence of a secondary discrimination task during the test phase. For both visual and auditory timing signals, participants reproduced longer durations when the secondary discrimination task required saccades to be made (i.e., overt attention shift) during reproduction as compared to when the discrimination task merely required fixation at screen center. Moreover, greater total saccade duration in a trial resulted in greater time distortion. However, in the visual modality, requiring participants to covertly shift attention (i.e., no saccade) to complete the discrimination task increased reproduced duration as much as making a saccade, whereas in the auditory modality making a saccade increased reproduced duration more than making a covert attention shift. In addition, we examined microsaccades in the conditions that did not require full saccades for both the visual and auditory experiments. Greater total microsaccade duration in a trial resulted in greater time distortion in both modalities. Taken together, the experiments suggest that saccades and microsaccades affect seconds range visual and auditory interval timing via attention and saccadic suppression mechanisms.
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31

Cotton, Philippa L., and Andrew T. Smith. "Contralateral Visual Hemifield Representations in the Human Pulvinar Nucleus." Journal of Neurophysiology 98, no. 3 (September 2007): 1600–1609. http://dx.doi.org/10.1152/jn.00419.2007.

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The pulvinar is a major nucleus of the thalamus. Macaque pulvinar includes two subregions that are connected to the visual cortex and are retinotopically organized, but the organizing principles of the visual portions of the human pulvinar are unknown. We employed two tasks to address the question of whether human pulvinar exhibits spatial organization using event-related functional magnetic resonance imaging. The first was a global-motion discrimination with a rich visual stimulus and the second a luminance-discrimination task of similar difficulty that used a minimal visual stimulus. Both tasks required central fixation and covert peripheral attention. A group analysis of blood-oxygen-level-dependent responses elicited in the motion-discrimination task revealed activity bilaterally in the ventral pulvinar ( z = 2 in Talairach space). Clear position specificity was observed with activity elicited only by contralateral stimuli. Ipsilateral stimuli caused suppression. This locus of activity is distinct from the more dorsal ( z = 10) region of the pulvinar that has previously been reported to be visually responsive but not retinotopic. In the luminance-discrimination task, similar activity was seen, but it was weaker and detectable only in the left pulvinar. In additional experiments with no task, passively viewed global-motion stimuli also activated the ventral pulvinar bilaterally. Our results show for the first time a distinct, bilateral visual representation in human inferior pulvinar that appears to be contralaterally organized.
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32

Saarinen, Jukka. "Rapid Discrimination of Visual Patterns in Children and Adults." Perceptual and Motor Skills 66, no. 1 (February 1988): 247–52. http://dx.doi.org/10.2466/pms.1988.66.1.247.

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Rapid visual discrimination in children (9 to 11 yr.) and adults was investigated using two tasks in which the subject had to search for a target pattern embedded in 35 background patterns. The time available for inspecting the search arrays was altered by varying the stimulus duration. In one task, there was a large difference in the feature or ‘texton’ content of patterns between the target and the background; in the other, this difference was small. In the first task, the children could detect the target pattern in a briefly flashed search array with high accuracy, because the target ‘popped out’ perceptually from the array, but in the second task the same detection rate was not reached until the stimulus duration was much longer, since a serial searching strategy was required. Results achieved by children and adults were similar. It seems that serial visual search is as efficient in children as in adults.
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33

Sovrano, Valeria Anna, Sofia Vicidomini, Davide Potrich, Maria Elena Miletto Petrazzini, Greta Baratti, and Orsola Rosa-Salva. "Visual discrimination and amodal completion in zebrafish." PLOS ONE 17, no. 3 (March 2, 2022): e0264127. http://dx.doi.org/10.1371/journal.pone.0264127.

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While zebrafish represent an important model for the study of the visual system, visual perception in this species is still less investigated than in other teleost fish. In this work, we validated for zebrafish two versions of a visual discrimination learning task, which is based on the motivation to reach food and companions. Using this task, we investigated zebrafish ability to discriminate between two different shape pairs (i.e., disk vs. cross and full vs. amputated disk). Once zebrafish were successfully trained to discriminate a full from an amputated disk, we also tested their ability to visually complete partially occluded objects (amodal completion). After training, animals were presented with two amputated disks. In these test stimuli, another shape was either exactly juxtaposed or only placed close to the missing sectors of the disk. Only the former stimulus should elicit amodal completion. In human observers, this stimulus causes the impression that the other shape is occluding the missing sector of the disk, which is thus perceived as a complete, although partially hidden, disk. In line with our predictions, fish reinforced on the full disk chose the stimulus eliciting amodal completion, while fish reinforced on the amputated disk chose the other stimulus. This represents the first demonstration of amodal completion perception in zebrafish. Moreover, our results also indicated that a specific shape pair (disk vs. cross) might be particularly difficult to discriminate for this species, confirming previous reports obtained with different procedures.
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34

Abrams, Alicia B., James M. Hillis, and David H. Brainard. "The Relation Between Color Discrimination and Color Constancy: When Is Optimal Adaptation Task Dependent?" Neural Computation 19, no. 10 (October 2007): 2610–37. http://dx.doi.org/10.1162/neco.2007.19.10.2610.

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Color vision supports two distinct visual functions: discrimination and constancy. Discrimination requires that the visual response to distinct objects within a scene be different. Constancy requires that the visual response to any object be the same across scenes. Across changes in scene, adaptation can improve discrimination by optimizing the use of the available response range. Similarly, adaptation can improve constancy by stabilizing the visual response to any fixed object across changes in illumination. Can common mechanisms of adaptation achieve these two goals simultaneously? We develop a theoretical framework for answering this question and present several example calculations. In the examples studied, the answer is largely yes when the change of scene consists of a change in illumination and considerably less so when the change of scene consists of a change in the statistical ensemble of surface reflectances in the environment.
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35

Flach, John M., and Paul M. Grunzke. "Automatic Processing through the Back Door." Proceedings of the Human Factors Society Annual Meeting 31, no. 9 (September 1987): 1054–56. http://dx.doi.org/10.1177/154193128703100929.

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This study examined performance in a consistent mapping visual search task in which subjects were required to make discriminations within the disjoint, target, and distractor sets as well as between the sets. The within set discrimination was variably mapped across blocks of trials. The results show strong practice effects consistent with the development of automatic processes.
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36

Vázquez, Pablo, Mónica Cano, and Carlos Acuña. "Discrimination of Line Orientation in Humans and Monkeys." Journal of Neurophysiology 83, no. 5 (May 1, 2000): 2639–48. http://dx.doi.org/10.1152/jn.2000.83.5.2639.

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Orientation discrimination, the capacity to recognize an orientation difference between two lines presented at different times, probably involves cortical processes such as stimuli encoding, holding them in memory, comparing them, and then deciding. To correlate discrimination with neural activity in combined psychophysical and electrophysiological experiments, precise knowledge of the strategies followed in the completion of the behavioral task is necessary. To address this issue, we measured human and nonhuman primates' capacities to discriminate the orientation of lines in a fixed and in a continuous variable task. Subjects have to indicate whether a line ( test) was oriented to one side or to the other of a previously presented line ( reference). When the orientation of the reference line did not change across trials (fixed discrimination task), subjects can complete the task either by categorizing the test line, thus ignoring the reference, or by discriminating between them. This ambiguity was avoided when the reference stimulus was changed randomly from trial to trial (continuos discrimination task), forcing humans and monkeys to discriminate by paying continuous attention to the reference and test stimuli. Both humans and monkeys discriminated accurately with stimulus duration as short as 150 ms. Effective interstimulus intervals were of 2.5 s for monkeys but much longer (>6 s) in humans. These results indicated that the fixed and continuous discrimination tasks are different, and accordingly humans and monkeys do use different behavioral strategies to complete each task. Because both tasks might involve different neural processes, these findings have important implications for studying the neural mechanisms underlying visual discrimination.
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Spitoni, Grazia Fernanda, Giorgio Pireddu, Valerio Zanellati, Beatrice Dionisi, Gaspare Galati, and Luigi Pizzamiglio. "Is Right Angular Gyrus Involved in the Metric Component of the Mental Body Representation in Touch and Vision? A tDCS Study." Brain Sciences 11, no. 3 (February 25, 2021): 284. http://dx.doi.org/10.3390/brainsci11030284.

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Several studies have found in the sense of touch a good sensory modality by which to study body representation. Here, we address the “metric component of body representation”, a specific function developed to process the discrimination of tactile distances on the body. The literature suggests the involvement of the right angular gyrus (rAG) in processing the tactile metricity on the body. The question of this study is the following: is the rAG also responsible for the visual metric component of body representation? We used tDCS (anodal and sham) in 20 subjects who were administered an on-body distance discrimination task with both tactile and visual stimuli. They were also asked to perform the same task in a near-body condition. The results allow us to confirm the role of rAG in the estimation of tactile distances. Further, we also showed that rAG might be involved in the discrimination of distances on the body not only in tactile but also in visual modality. Finally, based on the significant effects of anodal stimulation even in a near-body visual discrimination task, we proposed a higher-order function of the AG in terms of a supramodal comparator of quantities.
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38

Suzuishi, Yosuke, and Souta Hidaka. "Noninformative Vision of Body Movements can Enhance Tactile Discrimination." i-Perception 13, no. 1 (January 2022): 204166952110592. http://dx.doi.org/10.1177/20416695211059203.

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Vision of the body without task cues enhances tactile discrimination performance. This effect has been investigated only with static visual information, although our body usually moves, and dynamic visual and bodily information provides ownership (SoO) and agency (SoA) sensations to body parts. We investigated whether vision of body movements could enhance tactile discrimination performance. Participants observed white dots without any textural information showing lateral hand movements (dynamic condition) or static hands (static condition). For participants experiencing the dynamic condition first, it induced a lower tactile discrimination threshold, as well as a stronger SoO and SoA, compared to the static condition. For participants observing the static condition first, the magnitudes of the enhancement effect in the dynamic condition were positively correlated between the tactile discrimination and SoO/SoA. The enhancement of the dynamic visual information was not observed when the hand shape was not maintained in the scrambled white dot images. Our results suggest that dynamic visual information without task cues can enhance tactile discrimination performance by feeling SoO and SoA only when it maintains bodily information.
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39

Bausenhart, Karin M., Maria Dolores de la Rosa, and Rolf Ulrich. "Multimodal Integration of Time." Experimental Psychology 61, no. 4 (December 1, 2014): 310–22. http://dx.doi.org/10.1027/1618-3169/a000249.

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Recent studies suggest that the accuracy of duration discrimination for visually presented intervals is strongly impaired by concurrently presented auditory intervals of different duration, but not vice versa. Because these studies rely mostly on accuracy measures, it remains unclear whether this impairment results from changes in perceived duration or rather from a decrease in perceptual sensitivity. We therefore assessed complete psychometric functions in a duration discrimination task to disentangle effects on perceived duration and sensitivity. Specifically, participants compared two empty intervals marked by either visual or auditory pulses. These pulses were either presented unimodally, or accompanied by task-irrelevant pulses in the respective other modality, which defined conflicting intervals of identical, shorter, or longer duration. Participants were instructed to base their temporal judgments solely on the task-relevant modality. Despite this instruction, perceived duration was clearly biased toward the duration of the intervals marked in the task-irrelevant modality. This was not only found for the discrimination of visual intervals, but also, to a lesser extent, for the discrimination of auditory intervals. Discrimination sensitivity, however, was similar between all multimodal conditions, and only improved compared to the presentation of unimodal visual intervals. In a second experiment, evidence for multisensory integration was even found when the task-irrelevant modality did not contain any duration information, thus excluding noncompliant attention allocation as a basis of our results. Our results thus suggest that audiovisual integration of temporally discrepant signals does not impair discrimination sensitivity but rather alters perceived duration, presumably by means of a temporal ventriloquism effect.
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40

Spitzer, H., R. Desimone, and J. Moran. "Increased attention enhances both behavioral and neuronal performance." Science 240, no. 4850 (April 15, 1988): 338–40. http://dx.doi.org/10.1126/science.3353728.

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Single cells were recorded from cortical area V4 of two rhesus monkeys (Macaca mulatta) trained on a visual discrimination task with two levels of difficulty. Behavioral evidence indicated that the monkeys' discriminative abilities improved when the task was made more difficult. Correspondingly, neuronal responses to stimuli became larger and more selective in the difficult task. A control experiment demonstrated that changes in general arousal could not account for the effects of task difficulty on neuronal responses. It is concluded that increasing the amount of attention directed toward a stimulus can enhance the responsiveness and selectivity of the neurons that process it.
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41

Saarinen, Jukka. "Focal Visual Attention and Pattern Discrimination." Perception 22, no. 5 (May 1993): 509–15. http://dx.doi.org/10.1068/p220509.

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Pattern discrimination in the presence of distractor patterns is improved when the stimulus display is preceded by a precue designating the location of the target pattern. Experiments were conducted to determine how big an improvement the precue produced. The specific question of whether the observer is able to process selectively the stimulus pattern in the cued location of the display and ignore the patterns of the noncued locations was addressed. In order to study this, reaction time for pattern discrimination on a blank background (no distractors) was compared with the reaction time when the observer performed the same discrimination task in the presence of distractors and a precue had indicated the location of the stimulus pattern to be discriminated. The results showed that these two reaction times were equal if the cue preceded the stimulus patterns at intervals which were longer than some minimum time. Hence, stimuli outside the ‘aperture’ of focal attention can be ignored. These results could not be attributed to eye movements, because the longest duration of the whole sequence of precue and stimulus patterns was only 200 ms.
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42

Goertz, Ralf, Hennric Jokeit, and Erika Küchler. "Event related dynamics of 40 hz electroencephalogram during visual discrimination task." International Journal of Neuroscience 79, no. 3-4 (January 1994): 267–73. http://dx.doi.org/10.3109/00207459408986086.

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43

Stickgold, Robert, Dana Whidbee, Beth Schirmer, Vipul Patel, and J. Allan Hobson. "Visual Discrimination Task Improvement: A Multi-Step Process Occurring During Sleep." Journal of Cognitive Neuroscience 12, no. 2 (March 2000): 246–54. http://dx.doi.org/10.1162/089892900562075.

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Performance on a visual discrimination task shows longterm improvement after a single training session. When tested within 24 hr of training, improvement, was not observed unless subjects obtained at least 6 hr of postraining sleep prior to retesting, in which case improvement was proportional to the amount of sleep in excess of 6 hr. For subjects averaging 8 hr of sleep, overnight improvement was proportional to the amount of slow wave sleep (SWS) in the first quarter of the night, as well as the amount of rapid eye movement sleep (REM) in the last quarter. REM during the intervening 4 hr did not appear to contribute to improvement. A two-step process, modeling throughput as the product of the amount of early SWS and late REM, accounts for 80 percent of intersubject variance. These results suggest that, in the case of this visual discrimination task, both SWS and REM are required to consolidate experience-dependent neuronal changes into a form that supports improved task performance.
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Mishima, Kenichi, Megumi Fujii, and Michihiro Fujiwara. "A visual discrimination task with figures in rats and drugs evaluation." Japanese Journal of Pharmacology 76 (1998): 115. http://dx.doi.org/10.1016/s0021-5198(19)40578-7.

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45

Sanabria, Daniel, Juan Lupiáñez, and Charles Spence. "Auditory motion affects visual motion perception in a speeded discrimination task." Experimental Brain Research 178, no. 3 (March 13, 2007): 415–21. http://dx.doi.org/10.1007/s00221-007-0919-y.

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46

Minkwitz, Juliane, Maja U. Trenner, Christian Sander, Sebastian Olbrich, Abigail J. Sheldrick, Peter Schönknecht, Ulrich Hegerl, and Hubertus Himmerich. "Prestimulus vigilance predicts response speed in an easy visual discrimination task." Behavioral and Brain Functions 7, no. 1 (2011): 31. http://dx.doi.org/10.1186/1744-9081-7-31.

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47

Watanabe, Shigeru. "Effects of ectostriatal lesions on natural concept, pseudoconcept, and artificial pattern discrimination in pigeons." Visual Neuroscience 6, no. 5 (May 1991): 497–506. http://dx.doi.org/10.1017/s0952523800001346.

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AbstractPigeons were trained on four different visual discrimination tasks: (1) concept of natural stimuli (food vs. non-food object discrimination); (2) arbitrary classification of natural stimuli (pseudoconcept); (3) concept of artificial stimuli (triangles generated by computer graphics); and (4) discrimination of one pair of artificial stimuli. Then, lesions of the ectostriatum were carried out. The ectostriatal lesions impaired the arbitrary classification of natural stimuli and the concept of artificial pattern but did not impair the natural concept or the simple discrimination of fixed two stimuli. Lesions in the neostriatum did not cause deficits in any discrimination task. The birds had to learn individual stimuli for the arbitrary classification of stimuli and the stimulus generalization test after the artificial pattern concept discrimination indicated that the pigeons formed a concept more complicated than “triangle” in human language. These results suggest that the ectostriatum plays a role in task discrimination that requires much visual processing to classify stimuli.
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48

Senkowski, Daniel, and Christoph S. Herrmann. "Effects of task difficulty on evoked gamma activity and ERPs in a visual discrimination task." Clinical Neurophysiology 113, no. 11 (November 2002): 1742–53. http://dx.doi.org/10.1016/s1388-2457(02)00266-3.

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49

Gaynor, Leslie S., Rosie E. Curiel Cid, Ailyn Penate, Mónica Rosselli, Sara N. Burke, Meredith Wicklund, David A. Loewenstein, and Russell M. Bauer. "Visual Object Discrimination Impairment as an Early Predictor of Mild Cognitive Impairment and Alzheimer’s Disease." Journal of the International Neuropsychological Society 25, no. 7 (May 21, 2019): 688–98. http://dx.doi.org/10.1017/s1355617719000316.

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AbstractObjective:Detection of cognitive impairment suggestive of risk for Alzheimer’s disease (AD) progression is crucial to the prevention of incipient dementia. This study was performed to determine if performance on a novel object discrimination task improved identification of earlier deficits in older adults at risk for AD.Method:In total, 135 participants from the 1Florida Alzheimer’s Disease Research Center [cognitively normal (CN), Pre-mild cognitive impairment (PreMCI), amnestic mild cognitive impairment (aMCI), and dementia] completed a test of object discrimination and traditional memory measures in the context of a larger neuropsychological and clinical evaluation.Results:The Object Recognition and Discrimination Task (ORDT) revealed significant differences between the PreMCI, aMCI, and dementia groups versus CN individuals. Moreover, relative risk of being classified as PreMCI rather than CN increased as an inverse function of ORDT score.Discussion:Overall, the obtained results suggest that a novel object discrimination task improves the detection of very early AD-related cognitive impairment, increasing the window for therapeutic intervention. (JINS, 2019,25, 688–698)
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Haroush, Keren, Shaul Hochstein, and Leon Y. Deouell. "Momentary Fluctuations in Allocation of Attention: Cross-modal Effects of Visual Task Load on Auditory Discrimination." Journal of Cognitive Neuroscience 22, no. 7 (July 2010): 1440–51. http://dx.doi.org/10.1162/jocn.2009.21284.

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Even when our attention is dedicated to an important task, background processes monitor the environment for significant events. The mismatch negativity (MMN) event-related potential is thought to reflect such a monitoring process. Nevertheless, there is continuing debate concerning the susceptibility of the MMN to attentional manipulation. We investigated the trial-by-trial relationship between brain activity related to change detection, reflected in the MMN, and visual psychophysical performance—while varying task difficulty. We find that auditory change detection is indeed “automatic” in that MMN remains robust despite increasing (visual) task load. However, the MMN amplitude and latency are susceptible to both visual load and to momentary attentional fluctuations as reflected in success or failure to identify a following visual target. We conclude that background central auditory processing is sensitive to the demands of a visual task, and fluctuates based on moment-to-moment allocation of attentional resources to the visual task.
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