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Hess RF, Maehara G. Does cognitive perception have access to brief temporal events? Iperception 2011; 2:142-9. [PMID: 23145231 PMCID: PMC3485778 DOI: 10.1068/i0418] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 05/05/2011] [Indexed: 10/29/2022] Open
Abstract
To determine whether conscious perception has access to brief temporal event, we asked subjects in an odd-man out paradigm to determine which of the four Gaussian blobs was flickering asynchronously in time. We measure synchrony thresholds as a function of the base temporal frequency for spatially scaled stimuli in foveal and peripheral vision. The results are consistent with a time delay of around 67 milliseconds (ms) for foveal vision and 91 ms for peripheral vision. We conclude that conscious perception has access to only relatively long (∼67 ms) time events.
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Affiliation(s)
- Robert F Hess
- McGill Vision Research, Department of Ophthalmology, McGill University, Montreal, Quebec, Canada; e-mail:
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Rainville S, Clarke A. Distinct perceptual grouping pathways revealed by temporal carriers and envelopes. J Vis 2008; 8:9.1-15. [PMID: 19146293 PMCID: PMC4056025 DOI: 10.1167/8.15.9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Accepted: 09/01/2008] [Indexed: 11/24/2022] Open
Abstract
S. E. Guttman, L. A. Gilroy, and R. Blake (2005) investigated whether observers could perform temporal grouping in multi-element displays where each local element was stochastically modulated over time along one of several potential dimensions--or "messenger types"--such as contrast, position, orientation, or spatial scale. Guttman et al.'s data revealed that grouping discards messenger type and therefore support a single-pathway model that groups elements with similar temporal waveforms. In the current study, we carried out three experiments in which temporal-grouping information resided either in the carrier, the envelope, or the combined carrier and envelope of each messenger's timecourse. Results revealed that grouping is highly specific for messenger type if carrier envelopes lack grouping information but largely messenger nonspecific if carrier envelopes contain grouping information. These imply that temporal grouping is mediated by several messenger-specific carrier pathways as well as by a messenger-nonspecific envelope pathways. Findings also challenge simple temporal-filtering accounts of perceptual grouping (E. H. Adelson & H. Farid, 1999).
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Affiliation(s)
- Stéphane Rainville
- Center for Visual Neuroscience, Department of Psychology, North Dakota State University, Fargo, ND 58105, USA.
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Mirzajani A, Riyahi-Alam N, Oghabian MA, Saberi H, Firouznia K. Spatial frequency modulates visual cortical response to temporal frequency variation of visual stimuli: an fMRI study. Physiol Meas 2007; 28:547-54. [PMID: 17470987 DOI: 10.1088/0967-3334/28/5/008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The brain response to temporal frequency (TF) variation has already been reported, but with no study for different TF with respect to various spatial frequencies (SF). Functional magnetic resonance imaging (fMRI) was performed with a 1.5 Tesla General Electric system in 14 volunteers during square-wave reversal checkerboard visual stimulation with different temporal frequencies of 4, 6, 8 and 10 Hz in two states of low SF of 0.4 and high SF of 8 cpd (cycles/degree). The activation map was created using the data obtained from the block-designed fMRI study. Voxels whose Z value was above a threshold of 3.0, at a significance level P = 0.05, were considered activated. The results demonstrated that the percentage BOLD signal change in response to different TFs was the maximum value at 6 Hz for a high SF of 8 cpd, whereas it was the maximum at TF of 8 Hz for a low SF of 0.4 cpd. The results of this study agree with the results of animal invasive neurophysiological studies showing spatial and temporal frequency selectivity of neurons in visual cortical areas. These results can be useful for vision therapy (such as the treatment of amblyopia) and selecting a visual task in fMRI studies.
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Affiliation(s)
- A Mirzajani
- Department of Medical Physics, Tehran University of Medical Sciences, Tehran, Iran.
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Mirzajani A, Oghabian MA, Riyahi-Alam N, Saberi H, Firuznia K. Spatial frequency dependence of the human visual cortical response to temporal frequency modulation studied by fMRI. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2007; 2005:5802-3. [PMID: 17281577 DOI: 10.1109/iembs.2005.1615807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The brain response to temporal frequencies (TF) has been already reported, but with no study for different TF in respect to various spatial frequencies (SF). fMRI was performed by 1.5T GE-system in 14 volunteers during checkerboard visual stimulation, with TFs of 4, 6, 8 and 10Hz in low and high SFs of 0.5 and 8cpd. The averaged percentage BOLD signal changes demonstrated the amplitude of the fMRI response to different TFs which was maximally at 6Hz for high SF of 8cpd, and at 8Hz for low SF of 0.5cpd. The results are useful for vision therapy (such as the treatment of Amblyopia) and for fMRI applications incorporating visual tasks.
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Affiliation(s)
- A Mirzajani
- Department of Optometry, Iran University of, Medical Sciences and now PhD student with Department of Physics and, Biomedical Engineering, Tehran University of Medical Sciences (e-mail: )
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Rodgers KM, Benison AM, Barth DS. Two-Dimensional Coincidence Detection in the Vibrissa/Barrel Field. J Neurophysiol 2006; 96:1981-90. [PMID: 16790595 DOI: 10.1152/jn.00404.2006] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Coincidence detection in visual and auditory cortex may also be critical for feature analysis in somatosensory cortex. We examined its role in the rat posteromedial barrel subfield (PMBSF) using high-resolution arrays of epipial electrodes. Five vibrissae, forming an arc, row, or diagonal, were simultaneously or asynchronously stimulated to simulate contact with a straight edge of different angles at natural whisking velocities. Results indicated supralinear responses for both slow-wave and fast oscillations (FOs, about 350 Hz) at intervibrissa delays <2 ms. FO represented the earliest and most precisely tuned response to coincident vibrissa displacement. There was little difference in the spatiotemporal pattern of slow-wave or FO responses in the row, arc, or diagonal. This equivalence of function suggests that the PMBSF may be capable of working as a two-dimensional integrative array, processing spatial features based on coincidence detection despite the direction that the vibrissae pass across an object.
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Affiliation(s)
- Krista M Rodgers
- Department of Psychology, University of Colorado, Boulder, CO 80309-0345, USA
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Parton A, Dormer TH, Donnelly N, Usher M. Perceptual grouping based on temporal structure: Impact of subliminal flicker and visual transients. VISUAL COGNITION 2006. [DOI: 10.1080/13506280544000219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Mirzajani A, Oghabian MA, Riyahi-Alam N, Saberi H, Firouznia K, Bakhtiary M. Spatial frequency modulates the human visual cortical response to temporal frequency variation: an fMRI study. CONFERENCE PROCEEDINGS : ... ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL CONFERENCE 2006; 2006:1032-1035. [PMID: 17946438 DOI: 10.1109/iembs.2006.260078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The brain response to temporal frequencies (TF) has been already reported, but with no study for different TFs with respect to various spatial frequencies (SF). Functional Magnetic Resonance Imaging (fMRI) experiments were performed by 1.5 Tesla General Electric-system in 14 volunteers (9 males and 5 females, range 19-26 years) during square-wave reversal checkerboard visual stimulation with different temporal frequencies of 4, 6, 8 and 10 Hz in two states of low SF of 0.5 and high SF of 8 cpd (cycles/degree). The activation map was created using the data obtained from the block designed fMRI study. Pixels whose correlation coefficient value was above a threshold of 0.33, in significant level P<0.01 were considered activated. The average percentage BOLD (blood oxygenation level dependent) signal change for all activated pixels within the occipital lobe, multiplied by the total number of activated pixels within the occipital lobe, was used as the criterion for the strength of the fMRI signal at each state of TF&SF. The results demonstrated that the strength of the fMRI signal in response to different TFs was maximum in 6Hz for high SF of 8 cpd, while it was maximum at TF of 8Hz for low SF of 0.5 cpd. The results of this study agree with the results of animal invasive neurophysiological studies showing spatial and temporal frequency selectivity of neurons in visual cortical areas. These results can be useful for vision therapy (such as the treatment of Amblyopia) and selecting visual task in fMRI studies.
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Affiliation(s)
- A Mirzajani
- Medical Physics Department, Tehran University of Medical Sciences, Tehran, Iran.
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Samonds JM, Bonds AB. Gamma Oscillation Maintains Stimulus Structure-Dependent Synchronization in Cat Visual Cortex. J Neurophysiol 2005; 93:223-36. [PMID: 15282261 DOI: 10.1152/jn.00548.2004] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Visual cortical cells demonstrate both oscillation and synchronization, although the underlying causes and functional significance of these behaviors remain uncertain. We simultaneously recorded single-unit activity with microelectrode arrays in supragranular layers of area 17 of cats paralyzed and anesthetized with propofol and N2O. Rate-normalized autocorrelograms of 24 cells reveal bursting (100%) and gamma oscillation (63%). Renewal density analysis, used to explore the source of oscillation, suggests a contribution from extrinsic influences such as feedback. However, a bursting refractory period, presumably membrane-based, could also encourage oscillatory firing. When we investigated the source of synchronization for 60 cell pairs we found only moderate correlation of synchrony with bursts and oscillation. We did, nonetheless, discover a possible functional role for oscillation. In all cases of cross-correlograms that exhibited oscillation, the strength of the synchrony was maintained throughout the stimulation period. When no oscillation was apparent, 75% of the cell pairs showed decay in their synchronization. The synchrony between cells is strongly dependent on similar response onset latencies. We therefore propose that structured input, which yields tight organization of latency, is a more likely candidate for the source of synchronization than oscillation. The reliable synchrony at response onset could be driven by spatial and temporal correlation of the stimulus that is preserved through the earlier stages of the visual system. Oscillation then contributes to maintenance of the synchrony to enhance reliable transmission of the information for higher cognitive processing.
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Affiliation(s)
- Jason M Samonds
- Department of Electrical Engineering, Vanderbilt University, 255 Featheringill Hall, 400 24th Ave. South, Nashville, TN 37212, USA
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Abstract
Recent research on perceptual grouping is described with particular emphasis on identifying the level(s) at which grouping factors operate. Contrary to the classical view of grouping as an early, two-dimensional, image-based process, recent experimental results show that it is strongly influenced by phenomena related to perceptual constancy, such as binocular depth perception, lightness constancy, amodal completion, and illusory contours. These findings imply that at least some grouping processes operate at the level of phenomenal perception rather than at the level of the retinal image. Preliminary evidence is reported showing that grouping can affect perceptual constancy, suggesting that grouping processes must also operate at an early, preconstancy level. If so, grouping may be a ubiquitous, ongoing aspect of visual organization that occurs for each level of representation rather than as a single stage that can be definitively localized relative to other perceptual processes.
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Affiliation(s)
- Stephen E Palmer
- Department of Psychology, University of California, Berkeley, CA 94720, USA.
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Abstract
Temporal phase discrimination was measured as a function of spatial separation of the stimulus components. In contrast to many previous studies, phase discrimination thresholds were measured directly, rather than inferred from the ability to discriminate synchronous from antiphase stimuli, or from segregation or shape tasks. For abutting bars, relative phase thresholds were closely proportional to temporal frequency. The proportionality corresponded to a threshold temporal offset of 2.5-9.5 ms, across subjects. Introduction of a small gap (0.125 degrees or greater) led to a dramatic (3- to 7-fold) increase in thresholds for temporal phase discrimination, and thresholds were no longer proportional to temporal frequency. Insertion of a third bar filling the gap resulted in a recovery of the low thresholds, provided that its modulation was consistent with apparent motion across the three bars. Below 8 Hz, phase discrimination thresholds across three bars were equivalent to thresholds for two abutting bars. Above 8 Hz, phase discrimination thresholds for the three bar combination were lower than thresholds for two adjacent bars, implying that phase information was integrated across all three bars.Phase discrimination thresholds do not appear to reflect the properties of a single mechanism. Especially at high temporal frequencies, low thresholds for phase discrimination are closely tied to the presence of apparent motion. Temporal phase discrimination is markedly impaired by a small separation of stimulus components. Moreover, the inability to detect phase differences across gaps corresponds to the loss of phase-dependence of vernier acuity thresholds across gaps.
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Affiliation(s)
- Jonathan D Victor
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, NY 10021, USA.
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Blake R, Lee SH. Temporal Structure in the Input to Vision Can Promote Spatial Grouping. ACTA ACUST UNITED AC 2002. [DOI: 10.1007/3-540-45482-9_64] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023]
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