Visual Perceptual Learning in Human Object Recognition Areas: A Repetition Priming Study Using High-Density Electrical Mapping

Cognitive Neurophysiology Laboratory, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
NeuroImage (Impact Factor: 6.36). 03/2001; 13(2):305-13. DOI: 10.1006/nimg.2000.0684
Source: PubMed


It is often the case that only partial or degraded views of an object are available to an observer, and yet in many of these cases, object recognition is accomplished with surprising ease. The perceptual filling-in or "closure" that makes this possible has been linked to a group of object recognition areas in the human brain, the lateral occipital (LO) complex, and has been shown to have a specific electrophysiological correlate, the N(cl) component of the event related potential. Perceptual closure presumably occurs because repeated and varied exposure to different classes of objects has caused the brain to undergo "perceptual learning," which promotes a robust mnemonic representation, accessible under partial information circumstances. The present study examined the impact of perceptual learning on closure-related brain processes. Fragmented pictures of common objects were presented, such that information content was incrementally increased until just enough information was present to permit closure and object recognition. Periodic repetition of a subset of these picture sequences was used to induce repetition priming due to perceptual learning. This priming has an electrophysiological signature that is putatively generated in the LO complex, but significantly precedes the electrophysiological correlate of closure. The temporal progression of priming- and closure-related activity in the LO complex supports the view that sensory processing entails multiple reentrant stages of activity within processing modules of the visual hierarchy. That the earliest priming-related activity occurs over LO complex, suggests that the sensory trace itself may reside in these object recognition areas.

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Available from: John J Foxe, Oct 10, 2015
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    • "Without contextual information, guesses depend solely on how recognizable the object is. The brain responses thought to reflect those guesses, or what Stuss et al. (1992) called the generation of hypotheses of an object's identity, are reflected by more negative ERPs in time windows of 250–350 ms and 350– 450 ms (Doniger et al., 2001; Stuss et al., 1992). This effect was demonstrated by using fragmented images that, at a certain level of fragmentation, became unrecognizable. "
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    ABSTRACT: We are used to seeing objects in specific settings, and in association with other related objects. This contextual information allows for fast and efficient object recognition and influences brain-related processes. The influence of scene context has been studied using event-related potentials (ERPs) in order to further our understanding of the underlying brain mechanisms. Current ERP studies have focused on effects related to the incongruity between unambiguous objects and their scenes, rather than the specific influence of a congruent scene. The present study sought to examine ERPs associated with the beneficial influence of scene context on object recognition. This influence was examined using ambiguous objects that required a congruent scene in order to be recognized, as well as unambiguous objects, to determine whether scene processing occurs even when it is unnecessary for recognizing the object. Twenty healthy subjects were instructed to indicate whether they recognized, had a vague idea, or did not recognize target objects that appeared within congruent and neutral scenes. ERPs from 250 to 1000ms, including the N300 and N400, were more positive at anterior sites and more negative at posterior sites, when objects appeared in congruent scenes as opposed to when they appeared in neutral scenes, with a larger effect seen for ambiguous objects. Upon further examination, the results showed that the ERPs to ambiguous objects became similar to those of unambiguous objects when they appeared in congruent contexts. These findings indicated that a congruent context exerted its influence by reducing the ambiguity of objects. Copyright © 2015. Published by Elsevier Ltd.
    Neuropsychologia 04/2015; 72. DOI:10.1016/j.neuropsychologia.2015.04.023 · 3.30 Impact Factor
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    • "By creating these kinds of fragmented line drawings of objects, investigators can target the process of spatial integration whereby isolated local features are combined into a globally coherent figure. Fragmented figures allow one to assess quantitatively the effect of figure degradation on picture identification and to exploit figure degradation to study processes such as perceptual learning (Doniger et al., 2001a), visual priming (Snodgrass and Feenan, 1990), and implicit and explicit memory (Russo et al., 1995). Another popular stimulus strategy for studying perceptual organization involves the use of point-light (PL) animations to portray biological motion. "
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    ABSTRACT: WE LIVE IN A CLUTTERED, DYNAMIC VISUAL ENVIRONMENT THAT POSES A CHALLENGE FOR THE VISUAL SYSTEM: for objects, including those that move about, to be perceived, information specifying those objects must be integrated over space and over time. Does a single, omnibus mechanism perform this grouping operation, or does grouping depend on separate processes specialized for different feature aspects of the object? To address this question, we tested a large group of healthy young adults on their abilities to perceive static fragmented figures embedded in noise and to perceive dynamic point-light biological motion figures embedded in dynamic noise. There were indeed substantial individual differences in performance on both tasks, but none of the statistical tests we applied to this data set uncovered a significant correlation between those performance measures. These results suggest that the two tasks, despite their superficial similarity, require different segmentation and grouping processes that are largely unrelated to one another. Whether those processes are embodied in distinct neural mechanisms remains an open question.
    Frontiers in Psychology 10/2013; 4(9):795. DOI:10.3389/fpsyg.2013.00795 · 2.80 Impact Factor
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    • "Moreover, this negative component elicited by illusory contours was shown to originate in the LO complex (Shpaner, Murray, & Foxe, 2009; Murray et al., 2002). These findings are in accord with the present results and with the proposition that this early LO modulation reflects a rapid analysis of the configurational properties of a stimulus array or object (Doniger et al., 2001). Indeed, the tracking of the global configuration of multiple targets would seem to involve perceptual processes similar to those that segment shapes out of illusory contours. "
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    ABSTRACT: Human observers can readily track up to four independently moving items simultaneously, even in the presence of moving distractors. Here we combined EEG and magnetoencephalography recordings to investigate the neural processes underlying this remarkable capability. Participants were instructed to track four of eight independently moving items for 3 sec. When the movement ceased a probe stimulus consisting of four items with a higher luminance was presented. The location of the probe items could correspond fully, partly, or not at all with the tracked items. Participants reported whether the probe items fully matched the tracked items or not. About half of the participants showed slower RTs and higher error rates with increasing correspondence between tracked items and the probe. The other half, however, showed faster RTs and lower error rates when the probe fully matched the tracked items. This latter behavioral pattern was associated with enhanced probe-evoked neural activity that was localized to the lateral occipital cortex in the time range 170-210 msec. This enhanced response in the object-selective lateral occipital cortex suggested that these participants performed the tracking task by visualizing the overall shape configuration defined by the vertices of the tracked items, thereby producing a behavioral advantage on full-match trials. In a later time range (270-310 msec) probe-evoked neural activity increased monotonically as a function of decreasing target-probe correspondence in all participants. This later modulation, localized to superior parietal cortex, was proposed to reflect the degree of mismatch between the probe and the automatically formed visual STM representation of the tracked items.
    Journal of Cognitive Neuroscience 08/2013; 26(1). DOI:10.1162/jocn_a_00455 · 4.09 Impact Factor
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