Pop-out from abrupt visual onsets

Hancock, Peter; Phillips, William A.

doi:10.1016/s0042-6989(04)00220-2

Cited by 3 publications

(3 citation statements)

References 54 publications

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“…The scheme is supported by our data showing a strong relationship between the overall strength of cortical synchrony and the initial strength of the cortical synchrony (see also Fries et al 2001). The transient nature of the synchronization supports both models (Opara and Wörgötter 1996) and psychophysical data (Hancock and Phillips 2004;Lee and Blake 1999;Usher and Donnelly 1998) that suggest a fast cortical response latency-dependent form of binding that does not rely on top-down mechanisms. Our results also suggest that gamma oscillations maintain the transient form of synchrony so that the brain can retain and use this information for higher cognitive (i.e., top-down) processing.…”

Section: The Temporal Binding Theorysupporting

confidence: 79%

Gamma Oscillation Maintains Stimulus Structure-Dependent Synchronization in Cat Visual Cortex

Samonds

Bonds²

2005

Journal of Neurophysiology

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Samonds, Jason M. and A. B. Bonds. Gamma oscillation maintains stimulus structure-dependent synchronization in cat visual cortex. J Neurophysiol 93: [223][224][225][226][227][228][229][230][231][232][233][234][235][236] 2005. First published July 28, 2004; doi:10.1152/jn.00548.2004. 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 N 2 O. 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 crosscorrelograms 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. I N T R O D U C T I O NSensory perception relies on the classification of sensory information in relation to past experiences. A neurophysiological correlate has been described based on the relationships between neurons' spike trains and the formation of cell assemblies (Hayek 1952;Hebb 1949). The spatiotemporal relationships of spike trains provide a robust and flexible system of classification that provides enhancement through associations (Hebb 1949) and depends on contextual changes, as well as short-and long-term response history (Hayek 1952). Milner (1974) and von der Malsburg (1981) developed this theory to provide a framework for many perceptual phenomena that remain unexplained. Their elaborations are termed correlation theory or temporal binding theory, where perceptually related features are linked through correlated firing among subpopulations of cells. The original basis of the cell assembly theory was that relationships were formed between cells based on anatomical connections (Hayek 1952;Hebb 1949). However, acknowledging the dynamic and a...

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Section: The Temporal Binding Theorysupporting

confidence: 79%

Gamma Oscillation Maintains Stimulus Structure-Dependent Synchronization in Cat Visual Cortex

Samonds

Bonds²

2005

Journal of Neurophysiology

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“…Furthermore, it has been hypothesized that temporal precision to within 20 -30 ms has special significance in the neocortex because that is both the duration of the burst produced by apical amplification and the coincidence time window that leads to the burst (Larkum, Senn and Lüscher, 2004). This issue has been directly investigated by psychophysical studies of the effects of small differences in onset times on figure-ground segregation in the contour integration paradigm (Hancock and Phillips 2004;Hancock et al, 2008). Most, but not all, of the people tested could reliably detect contours hidden within the random background provided that their onset times differed by at least 20 -30 ms.…”

Section: Gestalt Groupingmentioning

confidence: 99%

On the functions, mechanisms, and malfunctions of intracortical contextual modulation

Phillips

Clark

Silverstein

2015

Neuroscience & Biobehavioral Reviews

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A broad neuron-centric conception of contextual modulation is reviewed and re-assessed in the light of recent neurobiological studies of amplification, suppression, and synchronization. Behavioural and computational studies of perceptual and higher cognitive functions that depend on these processes are outlined, and evidence that those functions and their neuronal mechanisms are impaired in schizophrenia is summarized. Finally, we compare and assess the long-term biological functions of contextual modulation at the level of computational theory as formalized by the theories of coherent infomax and free energy reduction. We conclude that those theories, together with the many empirical findings reviewed, show how contextual modulation at the neuronal level enables the cortex to flexibly adapt the use of its knowledge to current circumstances by amplifying and grouping relevant activities and by suppressing irrelevant activities.

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“…For the visual system it is known that multiple synchronized abrupt onsets are perceived as a whole (the Gestalt principle of 'common fate'), even when they contain a target that contrasts strongly with all others on several non-temporal features 33 . The transient neural activity induced by the onset of a stimulus probably increases with the number of stimulus items.…”

Section: Discussionmentioning

confidence: 99%

Vibrotactile target saliency

et al. 2008

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We tested the saliency of a single vibrotractile target (T) among 2 to 7 nontargets (N), presented by 8 tactors that were equally distributed over a horizontal band around the torso. Targets and nontargets had different pulse duration, but the same activation period and no onset asynchrony. T-N similarity was varied by changing the difference between T and N pulse duration. For target present trials the response times increased with the number of stimulus items for all conditions tested, suggesting a serial discrimination process. For target absent trials the response times were independent of the number of stimulus items, suggesting a parallel discrimination process. We found no effect of T-N similarity and no search asymmetry. The present results suggest that tactile target search is not comparable to visual search.

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Pop-out from abrupt visual onsets

Cited by 3 publications

References 54 publications

Gamma Oscillation Maintains Stimulus Structure-Dependent Synchronization in Cat Visual Cortex

Gamma Oscillation Maintains Stimulus Structure-Dependent Synchronization in Cat Visual Cortex

On the functions, mechanisms, and malfunctions of intracortical contextual modulation

Vibrotactile target saliency

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