Feature variability determines specificity and transfer in multiorientation feature detection learning.

Historically, in many perceptual learning experiments, only a single stimulus is practiced, and learning is often specific to the trained feature. Our prior work has demonstrated that multi-stimulus learning (e.g.

Contour integration deficits at high spatial frequencies in children treated for anisometropic amblyopia.

Purpose: This study was conducted to reexamine the question of whether children treated for anisometropic amblyopia have contour integration deficits. To do so, we used psychophysical methods that require global contour processing while minimizing the influence of low-level deficits: visibility, shape perception, and positional uncertainty.

Methods: Thirteen children with anisometropic amblyopia (age: 10.

The impact of training on the inner-outer asymmetry in crowding.

Inner-outer asymmetry, where the outer flanker induces stronger crowding than the inner flanker, is a hallmark property of visual crowding. It is unclear the contribution of inner-outer asymmetry to the pattern of crowding errors (biased predominantly toward the flanker identities) and the role of training on crowding errors. In a typical radial crowding display, 20 observers were asked to report the orientation of a target Gabor (7.

[Screening of differentially expressed genes for colorectal cancer and prediction of potential traditional Chinese medicine: based on bioinformatics].

This study screened and analyzed the differentially expressed genes(DEGs) between colorectal cancer(CRC) tissues and normal tissues with bioinformatics techniques to predict biomarkers and Chinese medicinals for the diagnosis and treatment of CRC. The microarray data sets GSE21815, GSE106582, and GSE41657 were downloaded from the Gene Expression Omnibus(GEO), and the DEGs were screened by GEO2 R, followed by the Gene Ontology(GO) tern enrichment and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis of the DEGs based on DAVID. The protein-protein interaction network was constructed by STRING, and MCODE and Cytohubba plug-ins were used to screen the significant modules and hub genes in the network.

Dichoptic Perceptual Training in Children With Amblyopia With or Without Patching History.

Purpose: Dichoptic training is becoming a popular tool in amblyopia treatment. Here we investigated the effects of dichoptic demasking training in children with amblyopia who never received patching treatment (NPT group) or were no longer responsive to patching (PT group).

Methods: Fourteen NPT and thirteen PT amblyopes (6-16.

Dichoptic De-Masking Learning in Adults With Amblyopia and Its Mechanisms.

Purpose: Recently, we reported that dichoptic de-masking training can further boost stereoacuity, but not visual acuity, in adults with amblyopia after extensive monocular perceptual training. Here, we investigated whether this dichoptic training targets on interocular suppression directly, or improves vision through high-level brain mechanisms.

Methods: Eleven adults with amblyopia first used amblyopic eyes (AEs) to perform contrast (n = 6) or orientation (n = 5) discrimination training, while resisting dichoptic noise masking from fellow eyes (FEs).

Vernier learning with short- and long-staircase training and its transfer to a new location with double training.

We previously demonstrated that perceptual learning of Vernier discrimination, when paired with orientation learning at the same retinal location, can transfer completely to untrained locations (Wang, Zhang, Klein, Levi, & Yu, 2014; Zhang, Wang, Klein, Levi, & Yu, 2011). However, Hung and Seitz (2014) reported that the transfer is possible only when Vernier is trained with short staircases, but not with very long staircases. Here we ran two experiments to examine Hung and Seitz's conclusions.

Dichoptic training in adults with amblyopia: Additional stereoacuity gains over monocular training.

Dichoptic training is a recent focus of research on perceptual learning in adults with amblyopia, but whether and how dichoptic training is superior to traditional monocular training is unclear. Here we investigated whether dichoptic training could further boost visual acuity and stereoacuity in monocularly well-trained adult amblyopic participants. During dichoptic training the participants used the amblyopic eye to practice a contrast discrimination task, while a band-filtered noise masker was simultaneously presented in the non-amblyopic fellow eye.

Bottom-up and top-down influences at untrained conditions determine perceptual learning specificity and transfer.

Perceptual learning is often orientation and location specific, which may indicate neuronal plasticity in early visual areas. However, learning specificity diminishes with additional exposure of the transfer orientation or location via irrelevant tasks, suggesting that the specificity is related to untrained conditions, likely because neurons representing untrained conditions are neither bottom-up stimulated nor top-down attended during training. To demonstrate these top-down and bottom-up contributions, we applied a "continuous flash suppression" technique to suppress the exposure stimulus into sub-consciousness, and with additional manipulations to achieve pure bottom-up stimulation or top-down attention with the transfer condition.

The transfer of motion direction learning to an opposite direction enabled by double training: A reply to Liang et al. (2015).

A recent paper from our lab (Zhang & Yang, 2014) reports that perceptual learning of motion-direction discrimination, which is known to be specific to the trained direction, can transfer significantly, and sometimes completely, to an opposite direction, provided that the observers receive additional exposure of the opposite direction via an irrelevant task. However, in a newly published study, Zili Liu and collaborators claim that they cannot replicate our original double training results using identical procedures (Liang, Fahle, & Liu, 2015). Here we point out that the relevant data in Liang et al.

Perceptual Learning at a Conceptual Level.

Unlabelled: Humans can learn to abstract and conceptualize the shared visual features defining an object category in object learning. Therefore, learning is generalizable to transformations of familiar objects and even to new objects that differ in other physical properties. In contrast, visual perceptual learning (VPL), improvement in discriminating fine differences of a basic visual feature through training, is commonly regarded as specific and low-level learning because the improvement often disappears when the trained stimulus is simply relocated or rotated in the visual field.

Perceptual learning of basic visual features remains task specific with Training-Plus-Exposure (TPE) training.

Visual perceptual learning is known to be specific to the trained retinal location, feature, and task. However, location and feature specificity can be eliminated by double-training or TPE training protocols, in which observers receive additional exposure to the transfer location or feature dimension via an irrelevant task besides the primary learning task Here we tested whether these new training protocols could even make learning transfer across different tasks involving discrimination of basic visual features (e.g.

Perceptual learning eases crowding by reducing recognition errors but not position errors.

When an observer reports a letter flanked by additional letters in the visual periphery, the response errors (the crowding effect) may result from failure to recognize the target letter (recognition errors), from mislocating a correctly recognized target letter at a flanker location (target misplacement errors), or from reporting a flanker as the target letter (flanker substitution errors). Crowding can be reduced through perceptual learning. However, it is not known how perceptual learning operates to reduce crowding.

Vernier perceptual learning transfers to completely untrained retinal locations after double training: a "piggybacking" effect.

Perceptual learning, a process in which training improves visual discrimination, is often specific to the trained retinal location, and this location specificity is frequently regarded as an indication of neural plasticity in the retinotopic visual cortex. However, our previous studies have shown that "double training" enables location-specific perceptual learning, such as Vernier learning, to completely transfer to a new location where an irrelevant task is practiced. Here we show that Vernier learning can be actuated by less location-specific orientation or motion-direction learning to transfer to completely untrained retinal locations.

Perceptual learning of contrast discrimination under roving: the role of semantic sequence in stimulus tagging.

Perceptual learning may occur when multiple contrasts are practiced in a fixed, but not in a roving (random), temporal sequence. However, learning may escape roving disruption when each contrast is assigned a letter tag (i.e.

Perceptual learning improves adult amblyopic vision through rule-based cognitive compensation.

Purpose: We investigated whether perceptual learning in adults with amblyopia could be enabled to transfer completely to an orthogonal orientation, which would suggest that amblyopic perceptual learning results mainly from high-level cognitive compensation, rather than plasticity in the amblyopic early visual brain.

Methods: Nineteen adults (mean age = 22.5 years) with anisometropic and/or strabismic amblyopia were trained following a training-plus-exposure (TPE) protocol.

Perceptual learning of motion direction discrimination transfers to an opposite direction with TPE training.

Motion direction learning is known to be specific to the trained direction. However, in this study we used our recently developed TPE (training-plus-exposure) method to demonstrate that motion direction learning can transfer to an opposite direction. Specifically, we first replicated the strict direction specificity of motion direction learning with a group of moving dots.

Whole report uncovers correctly identified but incorrectly placed target information under visual crowding.

Multiletter identification studies often find correctly identified letters being reported in wrong positions. However, how position uncertainty impacts crowding in peripheral vision is not fully understood. The observation of a flanker being reported as the central target cannot be taken as unequivocal evidence for position misperception because the observers could be biased to report a more identifiable flanker when failing to identify the central target.

Task relevancy and demand modulate double-training enabled transfer of perceptual learning.

Location-specific perceptual learning can be rendered transferrable to a new location with double training, in which feature training (e.g., contrast) is accompanied by additional location training at the new location even with an irrelevant task (e.

Rule-based learning explains visual perceptual learning and its specificity and transfer.

Visual perceptual learning models, as constrained by orientation and location specificities, propose that learning either reflects changes in V1 neuronal tuning or reweighting specific V1 inputs in either the visual cortex or higher areas. Here we demonstrate that, with a training-plus-exposure procedure, in which observers are trained at one orientation and either simultaneously or subsequently passively exposed to a second transfer orientation, perceptual learning can completely transfer to the second orientation in tasks known to be orientation-specific. However, transfer fails if exposure precedes the training.

Using geometric moments to explain human letter recognition near the acuity limit.

When the size of a letter stimulus is near the visual acuity limit of a human subject, details of the stimulus become unavailable due to ocular optical and neural filtering. In this study we tested the hypothesis that letter recognition near the acuity limit is dependent on more global features, which could be parsimoniously described by a few easy-to-visualize and perceptually meaningful low-order geometric moments (i.e.

Complete transfer of perceptual learning across retinal locations enabled by double training.

Practice improves discrimination of many basic visual features, such as contrast, orientation, and positional offset. Perceptual learning of many of these tasks is found to be retinal location specific, in that learning transfers little to an untrained retinal location. In most perceptual learning models, this location specificity is interpreted as a pointer to a retinotopic early visual cortical locus of learning.

Legibility of Chinese characters in peripheral vision and the top-down influences on crowding.

Written Chinese is distinct from alphabetic languages because of its enormous number of characters with a great range of spatial complexities (stroke numbers). In this study we investigated the impact of spatial complexity on legibility of Chinese characters as well as associated crowding in peripheral vision. Our results showed that for isolated characters, threshold sizes of complex characters increased faster with retinal eccentricity than did those of simple characters, suggesting possible "within-character" crowding among parts of complex Chinese characters.

Stimulus coding rules for perceptual learning.

Perceptual learning of visual features occurs when multiple stimuli are presented in a fixed sequence (temporal patterning), but not when they are presented in random order (roving). This points to the need for proper stimulus coding in order for learning of multiple stimuli to occur. We examined the stimulus coding rules for learning with multiple stimuli.