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Tanrıkulu ÖD, Froyen V, Feldman J, Singh M. Interaction of contour geometry and optic flow in determining relative depth of surfaces. Atten Percept Psychophys 2024; 86:221-236. [PMID: 37935897 DOI: 10.3758/s13414-023-02807-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2023] [Indexed: 11/09/2023]
Abstract
Dynamic occlusion, such as the accretion and deletion of texture near a boundary, is a major factor in determining relative depth of surfaces. However, the shape of the contour bounding the dynamic texture can significantly influence what kind of 3D shape, and what relative depth, are conveyed by the optic flow. This can lead to percepts that are inconsistent with traditional accounts of shape and depth from motion, where accreting/deleting texture can indicate the figural region, and/or 3D rotation can be perceived despite the constant speed of the optic flow. This suggests that the speed profile of the dynamic texture and the shape of its bounding contours combine to determine relative depth in a way that is not explained by existing models. Here, we investigated how traditional structure-from-motion principles and contour geometry interact to determine the relative-depth interpretation of dynamic textures. We manipulated the consistency of the dynamic texture with rotational or translational motion by varying the speed profile of the texture. In Experiment 1, we used a multi-region figure-ground display consisting of regions with dots moving horizontally in opposite directions in adjacent regions. In Experiment 2, we used stimuli including two regions separated by a common border, with dot textures moving horizontally in opposite directions. Both contour geometry (convexity) and the speed profile of the dynamic dot texture influenced relative-depth judgments, but contour geometry was the stronger factor. The results underscore the importance of contour geometry, which most current models disregard, in determining depth from motion.
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Affiliation(s)
| | - Vicky Froyen
- Department of Psychology, Center for Cognitive Science, Rutgers University, Piscataway, USA
| | - Jacob Feldman
- Department of Psychology, Center for Cognitive Science, Rutgers University, Piscataway, USA
| | - Manish Singh
- Department of Psychology, Center for Cognitive Science, Rutgers University, Piscataway, USA
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2
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Gray SL, Qadri MAJ, Cook RG. Dynamically occluded action recognition by pigeons. Atten Percept Psychophys 2023; 85:2515-2530. [PMID: 36918511 DOI: 10.3758/s13414-023-02668-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2023] [Indexed: 03/16/2023]
Abstract
Identifying the behaviors of organisms is essential for an animal's survival. This ability is particularly challenged when the "actors" are dynamically occluded by other objects and become fragmented as they move through an environment. Even when fragmented in time and across space, humans readily recognize the behavior of these dynamically occluded objects and actors. How animals process such fragmented information, especially when involving motion, remains uncertain. In three experiments, we investigated the ability of six pigeons to discriminate between the running and walking actions of digital animal models when dynamically occluded. The pigeons were tested in a go/no-go procedure using three models that transited behind multiple occluders in a semirealistic scene. Without ever seeing the entirety of the animal model at one time, all the pigeons learned to discriminate among these two behaviors. This discrimination transferred to an unfamiliar model, transit direction, transiting rates, camera perspectives, and occluders. Tests with different static and dynamic features indicated that the pigeons relied on motion features for the discrimination, especially articulated motion. These experiments demonstrate that pigeons, like humans, can discriminate actions even when their view of the actor is fragmented in time and space.
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Affiliation(s)
- Suzanne L Gray
- Department of Psychology, Tufts University, 490 Boston Ave, Medford, MA, 02155, USA.
| | | | - Robert G Cook
- Department of Psychology, Tufts University, 490 Boston Ave, Medford, MA, 02155, USA
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3
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Gurariy G, Randall R, Greenberg AS. Neuroimaging evidence for the direct role of auditory scene analysis in object perception. Cereb Cortex 2023; 33:6257-6272. [PMID: 36562994 PMCID: PMC10183742 DOI: 10.1093/cercor/bhac501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
Auditory Scene Analysis (ASA) refers to the grouping of acoustic signals into auditory objects. Previously, we have shown that perceived musicality of auditory sequences varies with high-level organizational features. Here, we explore the neural mechanisms mediating ASA and auditory object perception. Participants performed musicality judgments on randomly generated pure-tone sequences and manipulated versions of each sequence containing low-level changes (amplitude; timbre). Low-level manipulations affected auditory object perception as evidenced by changes in musicality ratings. fMRI was used to measure neural activation to sequences rated most and least musical, and the altered versions of each sequence. Next, we generated two partially overlapping networks: (i) a music processing network (music localizer) and (ii) an ASA network (base sequences vs. ASA manipulated sequences). Using Representational Similarity Analysis, we correlated the functional profiles of each ROI to a model generated from behavioral musicality ratings as well as models corresponding to low-level feature processing and music perception. Within overlapping regions, areas near primary auditory cortex correlated with low-level ASA models, whereas right IPS was correlated with musicality ratings. Shared neural mechanisms that correlate with behavior and underlie both ASA and music perception suggests that low-level features of auditory stimuli play a role in auditory object perception.
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Affiliation(s)
- Gennadiy Gurariy
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, 8701 W Watertown Plank Rd, Milwaukee, WI 53233, United States
| | - Richard Randall
- School of Music and Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA 15213, United States
| | - Adam S Greenberg
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, 8701 W Watertown Plank Rd, Milwaukee, WI 53233, United States
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Gurariy G, Mruczek REB, Snow JC, Caplovitz GP. Using High-Density Electroencephalography to Explore Spatiotemporal Representations of Object Categories in Visual Cortex. J Cogn Neurosci 2022; 34:967-987. [PMID: 35286384 PMCID: PMC9169880 DOI: 10.1162/jocn_a_01845] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Visual object perception involves neural processes that unfold over time and recruit multiple regions of the brain. Here, we use high-density EEG to investigate the spatiotemporal representations of object categories across the dorsal and ventral pathways. In , human participants were presented with images from two animate object categories (birds and insects) and two inanimate categories (tools and graspable objects). In , participants viewed images of tools and graspable objects from a different stimulus set, one in which a shape confound that often exists between these categories (elongation) was controlled for. To explore the temporal dynamics of object representations, we employed time-resolved multivariate pattern analysis on the EEG time series data. This was performed at the electrode level as well as in source space of two regions of interest: one encompassing the ventral pathway and another encompassing the dorsal pathway. Our results demonstrate shape, exemplar, and category information can be decoded from the EEG signal. Multivariate pattern analysis within source space revealed that both dorsal and ventral pathways contain information pertaining to shape, inanimate object categories, and animate object categories. Of particular interest, we note striking similarities obtained in both ventral stream and dorsal stream regions of interest. These findings provide insight into the spatio-temporal dynamics of object representation and contribute to a growing literature that has begun to redefine the traditional role of the dorsal pathway.
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5
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Freud E, Behrmann M, Snow JC. What Does Dorsal Cortex Contribute to Perception? Open Mind (Camb) 2020; 4:40-56. [PMID: 33225195 PMCID: PMC7672309 DOI: 10.1162/opmi_a_00033] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 05/20/2020] [Indexed: 01/26/2023] Open
Abstract
According to the influential "Two Visual Pathways" hypothesis, the cortical visual system is segregated into two pathways, with the ventral, occipitotemporal pathway subserving object perception, and the dorsal, occipitoparietal pathway subserving the visuomotor control of action. However, growing evidence suggests that the dorsal pathway also plays a functional role in object perception. In the current article, we present evidence that the dorsal pathway contributes uniquely to the perception of a range of visuospatial attributes that are not redundant with representations in ventral cortex. We describe how dorsal cortex is recruited automatically during perception, even when no explicit visuomotor response is required. Importantly, we propose that dorsal cortex may selectively process visual attributes that can inform the perception of potential actions on objects and environments, and we consider plausible developmental and cognitive mechanisms that might give rise to these representations. As such, we consider whether naturalistic stimuli, such as real-world solid objects, might engage dorsal cortex more so than simplified or artificial stimuli such as images that do not afford action, and how the use of suboptimal stimuli might limit our understanding of the functional contribution of dorsal cortex to visual perception.
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Affiliation(s)
- Erez Freud
- Department of Psychology and the Centre for Vision Research, York University
| | - Marlene Behrmann
- Department of Psychology and the Neuroscience Institute, Carnegie Mellon University
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7
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Indication of quantum mechanical electron transport in human substantia nigra tissue from conductive atomic force microscopy analysis. Biosystems 2019; 179:30-38. [PMID: 30826349 DOI: 10.1016/j.biosystems.2019.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/28/2019] [Accepted: 02/05/2019] [Indexed: 12/18/2022]
Abstract
Neuromelanin and ferritin in dopamine neurons of the substantia nigra have a distribution and density that is similar to disordered arrays of quantum dots in photovoltaic devices, which have been experimentally shown to conduct electric energy using quantum mechanical electron transport mechanisms. Conductive atomic force microscopy tests were performed on human substantia nigra tissue at room temperature, to determine whether evidence of electron transport is present. The test results presented here provide evidence of quantum mechanical electron transport from ferritin and neuromelanin at levels that may be sufficient to cause or contribute to generation of action potentials.
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Darcy N, Sterzer P, Hesselmann G. Category-selective processing in the two visual pathways as a function of stimulus degradation by noise. Neuroimage 2018; 188:785-793. [PMID: 30592972 DOI: 10.1016/j.neuroimage.2018.12.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/23/2018] [Accepted: 12/16/2018] [Indexed: 11/29/2022] Open
Abstract
Understanding the organising principles and functional properties of the primate brain's numerous visually responsive cortical regions is one of the major goals in cognitive neuroscience. Functional magnetic resonance imaging (fMRI) studies have revealed that neural responses in higher-order visual cortex are shaped by object categories, task context, and spatiotemporal regularities. Beyond these properties, visual processing in the ventral pathway has been shown to be tightly linked to perceptual awareness, while the evidence regarding dorsal visual processing and awareness is mixed. Most previous studies targeting the dorsal pathway have used dichotomous "visible versus invisible" experimental designs and interocular suppression paradigms to modulate stimulus visibility. In this fMRI study, we sought to investigate category-selective processing of faces and tools in the ventral and dorsal visual streams as a function of parametric stimulus degradation by noise. Both frequentist and Bayesian statistics provide strong evidence for a linear relationship between category-selective processing and stimulus information in both visual pathways. Overall, multivariate category decoding accuracies turned out to be lower in the dorsal pathway. We discuss our results within the context of the emerging notion of highly interconnected visual streams, and provide an outlook on how future studies may help to further refine our understanding of the functional role of the dorsal pathway in visual object processing.
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Affiliation(s)
- N Darcy
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117, Berlin, Germany
| | - P Sterzer
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117, Berlin, Germany
| | - G Hesselmann
- Visual Perception Laboratory, Department of Psychiatry and Psychotherapy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, 10117, Berlin, Germany.
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Erlikhman G, Caplovitz GP, Gurariy G, Medina J, Snow JC. Towards a unified perspective of object shape and motion processing in human dorsal cortex. Conscious Cogn 2018; 64:106-120. [PMID: 29779844 DOI: 10.1016/j.concog.2018.04.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/20/2018] [Accepted: 04/26/2018] [Indexed: 01/06/2023]
Abstract
Although object-related areas were discovered in human parietal cortex a decade ago, surprisingly little is known about the nature and purpose of these representations, and how they differ from those in the ventral processing stream. In this article, we review evidence for the unique contribution of object areas of dorsal cortex to three-dimensional (3-D) shape representation, the localization of objects in space, and in guiding reaching and grasping actions. We also highlight the role of dorsal cortex in form-motion interaction and spatiotemporal integration, possible functional relationships between 3-D shape and motion processing, and how these processes operate together in the service of supporting goal-directed actions with objects. Fundamental differences between the nature of object representations in the dorsal versus ventral processing streams are considered, with an emphasis on how and why dorsal cortex supports veridical (rather than invariant) representations of objects to guide goal-directed hand actions in dynamic visual environments.
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Affiliation(s)
| | | | - Gennadiy Gurariy
- Department of Psychology, University of Nevada, Reno, USA; Department of Psychology, University of Wisconsin, Milwaukee, USA
| | - Jared Medina
- Department of Psychological and Brain Sciences, University of Delaware, USA
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10
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Meier K, Partanen M, Giaschi D. Neural Correlates of Speed-Tuned Motion Perception in Healthy Adults. Perception 2018; 47:660-683. [PMID: 29683390 DOI: 10.1177/0301006618771463] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
It has been suggested that slow and medium-to-fast speeds of motion may be processed by at least partially separate mechanisms. The purpose of this study was to establish the cortical areas activated during motion-defined form and global motion tasks as a function of speed, using functional magnetic resonance imaging. Participants performed discrimination tasks with random dot stimuli at high coherence, at coherence near their own thresholds, and for random motion. Stimuli were moving at 0.1 or 5 deg/s. In the motion-defined form task, lateral occipital complex, V5/MT+ and intraparietal sulcus showed greater activation by high or near-threshold coherence than by random motion stimuli; V5/MT+ and intraparietal sulcus demonstrated greater activation for 5 than 0.1 deg/s dot motion. In the global motion task, only high coherence stimuli elicited significant activation over random motion; this activation was primarily in nonclassical motion areas. V5/MT+ was active for all motion conditions and showed similar activation for coherent and random motion. No regions demonstrated speed-tuning effects for global motion. These results suggest that similar cortical systems are activated by slow- and medium-speed stimuli during these tasks in healthy adults.
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Affiliation(s)
- Kimberly Meier
- Department of Psychology, 8166 University of British Columbia , Vancouver, British Columbia, Canada
| | - Marita Partanen
- Department of Education and Counselling Psychology and Special Education, 8166 University of British Columbia , Vancouver, British Columbia, Canada
| | - Deborah Giaschi
- Department of Ophthalmology and Visual Sciences, 8166 University of British Columbia , Vancouver, British Columbia, Canada
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11
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Piccini G, Menghini D, D'Andrea A, Caciolo C, Pontillo M, Armando M, Perrino F, Mandolesi L, Salerni A, Buzzonetti L, Digilio MC, Zampino G, Tartaglia M, Benassi M, Vicari S, Alfieri P. Visual perception skills: a comparison between patients with Noonan syndrome and 22q11.2 deletion syndrome. GENES BRAIN AND BEHAVIOR 2017; 16:627-634. [PMID: 28378436 DOI: 10.1111/gbb.12381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/14/2017] [Accepted: 03/28/2017] [Indexed: 01/21/2023]
Abstract
Ventral and dorsal streams are visual pathways deputed to transmit information from the photoreceptors of the retina to the lateral geniculate nucleus and then to the primary visual cortex (V1). Several studies investigated whether one pathway is more vulnerable than the other during development, and whether these streams develop at different rates. The results are still discordant. The aim of the present study was to understand the functionality of the dorsal and the ventral streams in two populations affected by different genetic disorders, Noonan syndrome (NS) and 22q11.2 deletion syndrome (22q11.2DS), and explore the possible genotype-phenotype relationships. 'Form coherence' abilities for the ventral stream and 'motion coherence' abilities for the dorsal stream were evaluated in 19 participants with NS and 20 participants with 22q11.2DS. Collected data were compared with 55 age-matched controls. Participants with NS and 22q11.2DS did not differ in the form coherence task, and their performance was significantly lower than that of controls. However, in the motion coherence task, the group with NS and controls did not differ, and both obtained significantly higher scores than the group with 22q11.2DS. Our findings indicate that deficits in the dorsal stream are related to the specific genotype, and that in our syndromic groups the ventral stream is more vulnerable than the dorsal stream.
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Affiliation(s)
- G Piccini
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - D Menghini
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - A D'Andrea
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, University "G.d'Annunzio", Chieti-Pescara, Italy
| | - C Caciolo
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - M Pontillo
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - M Armando
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - F Perrino
- Center for Rare Diseases, Department of Pediatrics, Polo Salute Donna e Bambino, Fondazione Policlinico Universitario A. Gemelli, Catholic University, Rome, Italy
| | - L Mandolesi
- Psychology Department, University of Bologna, Bologna, Italy
| | - A Salerni
- Institute of Ophthalmology, Catholic University, Rome, Italy
| | - L Buzzonetti
- Ophthalmology Department, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - M C Digilio
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - G Zampino
- Center for Rare Diseases, Department of Pediatrics, Polo Salute Donna e Bambino, Fondazione Policlinico Universitario A. Gemelli, Catholic University, Rome, Italy
| | - M Tartaglia
- Genetics and Rare Diseases Research Division, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - M Benassi
- Psychology Department, University of Bologna, Bologna, Italy
| | - S Vicari
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - P Alfieri
- Department of Neuroscience, Child Neuropsychiatric Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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12
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Johnston R, Pitchford NJ, Roach NW, Ledgeway T. Encoding of rapid time-varying information is impaired in poor readers. J Vis 2017; 17:1. [PMID: 28460376 PMCID: PMC5412969 DOI: 10.1167/17.5.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 03/24/2017] [Indexed: 11/24/2022] Open
Abstract
A characteristic set of eye movements and fixations are made during reading, so the position of words on the retinae is constantly being updated. Effective decoding of print requires this temporal stream of visual information to be segmented or parsed into its constituent units (e.g., letters or words). Poor readers' difficulties with word recognition could arise at the point of segmenting time-varying visual information, but the mechanisms underlying this process are little understood. Here, we used random-dot displays to explore the effects of reading ability on temporal segmentation. Thirty-eight adult readers viewed test stimuli that were temporally segmented by constraining either local motions or analogous form cues to oscillate back and fourth at each of a range of rates. Participants had to discriminate these segmented patterns from comparison stimuli containing the same motion and form cues but these were temporally intermingled. Results showed that the motion and form tasks could not be performed reliably when segment duration was shorter than a temporal resolution (acuity) limit. The acuity limits for both tasks were significantly and negatively correlated with reading scores. Importantly, the minimum segment duration needed to detect the temporally segmented stimuli was longer in relatively poor readers than relatively good readers. This demonstrates that adult poor readers have difficulty segmenting temporally changing visual input particularly at short segment durations. These results are consistent with evidence suggesting that precise encoding of rapid time-varying information is impaired in developmental dyslexia.
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Affiliation(s)
- Richard Johnston
- School of Psychology, The University of Nottingham, University Park, Nottingham, UK
| | - Nicola J Pitchford
- School of Psychology, The University of Nottingham, University Park, Nottingham, UK
| | - Neil W Roach
- School of Psychology, The University of Nottingham, University Park, Nottingham, UK
| | - Timothy Ledgeway
- School of Psychology, The University of Nottingham, University Park, Nottingham, UK
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Erlikhman G, Caplovitz GP. Decoding information about dynamically occluded objects in visual cortex. Neuroimage 2016; 146:778-788. [PMID: 27663987 DOI: 10.1016/j.neuroimage.2016.09.024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Revised: 08/19/2016] [Accepted: 09/11/2016] [Indexed: 11/28/2022] Open
Abstract
During dynamic occlusion, an object passes behind an occluding surface and then later reappears. Even when completely occluded from view, such objects are experienced as continuing to exist or persist behind the occluder even though they are no longer visible. The contents and neural basis of this persistent representation remain poorly understood. Questions remain as to whether there is information maintained about the object itself (i.e. its shape or identity) or non-object-specific information such as its position or velocity as it is tracked behind an occluder, as well as which areas of visual cortex represent such information. Recent studies have found that early visual cortex is activated by "invisible" objects during visual imagery and by unstimulated regions along the path of apparent motion, suggesting that some properties of dynamically occluded objects may also be neurally represented in early visual cortex. We applied functional magnetic resonance imaging in human subjects to examine representations within visual cortex during dynamic occlusion. For gradually occluded, but not for instantly disappearing objects, there was an increase in activity in early visual cortex (V1, V2, and V3). This activity was spatially-specific, corresponding to the occluded location in the visual field. However, the activity did not encode enough information about object identity to discriminate between different kinds of occluded objects (circles vs. stars) using MVPA. In contrast, object identity could be decoded in spatially-specific subregions of higher-order, topographically organized areas such as ventral, lateral, and temporal occipital areas (VO, LO, and TO) as well as the functionally defined LOC and hMT+. These results suggest that early visual cortex may only represent the dynamically occluded object's position or motion path, while later visual areas represent object-specific information.
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Freud E, Plaut DC, Behrmann M. 'What' Is Happening in the Dorsal Visual Pathway. Trends Cogn Sci 2016; 20:773-784. [PMID: 27615805 DOI: 10.1016/j.tics.2016.08.003] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 08/05/2016] [Accepted: 08/08/2016] [Indexed: 01/01/2023]
Abstract
The cortical visual system is almost universally thought to be segregated into two anatomically and functionally distinct pathways: a ventral occipitotemporal pathway that subserves object perception, and a dorsal occipitoparietal pathway that subserves object localization and visually guided action. Accumulating evidence from both human and non-human primate studies, however, challenges this binary distinction and suggests that regions in the dorsal pathway contain object representations that are independent of those in ventral cortex and that play a functional role in object perception. We review here the evidence implicating dorsal object representations, and we propose an account of the anatomical organization, functional contributions, and origins of these representations in the service of perception.
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Affiliation(s)
- Erez Freud
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, Carnegie Mellon University and the University of Pittsburgh, Pittsburgh, PA, USA.
| | - David C Plaut
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, Carnegie Mellon University and the University of Pittsburgh, Pittsburgh, PA, USA
| | - Marlene Behrmann
- Department of Psychology, Carnegie Mellon University, Pittsburgh, PA, USA; Center for the Neural Basis of Cognition, Carnegie Mellon University and the University of Pittsburgh, Pittsburgh, PA, USA
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