Perceptual learning modifies the functional specializations of visual cortical areas

Abstract

Training can improve performance of perceptual tasks. This phenomenon, known as perceptual learning, is strongest for the trained task and stimulus, leading to a widely accepted assumption that the associated neuronal plasticity is restricted to brain circuits that mediate performance of the trained task. Nevertheless, learning does transfer to other tasks and stimuli, implying the presence of more widespread plasticity. Here, we trained human subjects to discriminate the direction of coherent motion stimuli. The behavioral learning effect substantially transferred to noisy motion stimuli. We used transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) to investigate the neural mechanisms underlying the transfer of learning. The TMS experiment revealed dissociable, causal contributions of V3A (one of the visual areas in the extrastriate visual cortex) and MT+ (middle temporal/medial superior temporal cortex) to coherent and noisy motion processing. Surprisingly, the contribution of MT+ to noisy motion processing was replaced by V3A after perceptual training. The fMRI experiment complemented and corroborated the TMS finding. Multivariate pattern analysis showed that, before training, among visual cortical areas, coherent and noisy motion was decoded most accurately in V3A and MT+, respectively. After training, both kinds of motion were decoded most accurately in V3A. Our findings demonstrate that the effects of perceptual learning extend far beyond the retuning of specific neural populations for the trained stimuli. Learning could dramatically modify the inherent functional specializations of visual cortical areas and dynamically reweight their contributions to perceptual decisions based on their representational qualities. These neural changes might serve as the neural substrate for the transfer of perceptual learning.perceptual learning | motion | psychophysics | transcranial magnetic stimulation | functional magnetic resonance imaging P erceptual learning, an enduring improvement in the performance of a sensory task resulting from practice, has been widely used as a model to study experience-dependent cortical plasticity in adults (1). However, at present, there is no consensus on the nature of the neural mechanisms underlying this type of learning. Perceptual learning is often specific to the physical properties of the trained stimulus, leading to the hypothesis that the underlying neural changes occur in sensory coding areas (2). Electrophysiological and brain imaging studies have shown that visual perceptual learning alters neural response properties in primary visual cortex (3, 4) and extrastriate areas including V4 (5) and MT+ (middle temporal/medial superior temporal cortex) (6), as well as object selective areas in the inferior temporal cortex (7,8). An alternative hypothesis proposes that perceptual learning is mediated by downstream cortical areas that are responsible for attentional allocation and/or decision-making, such as the intraparietal sulcus (IPS) and anterior...

Global motion perception is related to motor function in 4.5-year-old children born at risk of abnormal development

“…The observer’s task is to detect the direction of the coherent signal dots and the relative proportion of signal to noise in the stimulus can be varied to estimate a motion coherence threshold (the percentage of signal dots required for a particular level of task performance) (Newsome & Pare, 1988). It is well established that V5, a component of the dorsal stream, plays a central role in detecting coherent motion in RDKs (Cai, Chen, Zhou, Thompson, & Fang, 2014; Chen, Cai, Zhou, Thompson, & Fang, 2016; Newsome & Pare, 1988; Rudolph & Pasternak, 1999). However, the extent to which performance on a global motion task reflects the function of higher-level dorsal stream areas such as the posterior parietal cortex is unclear.…”

Neural mechanisms of motion perceptual learning in noise

“…When multiple visual areas participate in the information processing for a task, would perceptual learning trigger reweighting at the regional level? Take motion processing for example, MT and V3A are recognized as two key areas in the human brain [Bartels et al, ; Orban et al, ; Tootell et al, ], and their involvement in motion perceptual learning has been demonstrated in several brain imaging studies [Chen et al, ; Shibata et al, ; Tompson et al, ; Vaina et al, ]. Previously, we found motion direction discrimination training sharpened the cortical tuning for the trained motion direction in area V3A, and enhanced the connectivity from V3A to the motion‐decision making area IPS (intraparietal sulcus) [Chen et al, ].…”

Visual training improves perceptual grouping based on basic stimulus features

“…Further investigation of training effects on grouping ability on alternate patterns would further probe specificity of grouping training, and whether effects are restricted to stimulus representations used in training conditions (Crist et al, 1997;A. A. Schoups et al, 1995), or if training affects more general mechanisms (Chen et al 2016;Z. Liu, 1999;Zhang et al, 2010).…”

“…With other conditions, perceptual learning generalizes beyond stimuli used during training (Z. Liu, 1999;Zhang, Xiao, Klein, Levi, & Yu, 2010), suggesting more widespread effects across neural systems (Chen, Cai, Zhou, Thompson, & Fang, 2016).…”