Byers Anna, Serences John T
Department of Psychology, University of California, San Diego, California.
Department of Psychology, University of California, San Diego, California Neurosciences Graduate Program, University of California, San Diego, California
J Neurophysiol. 2014 Sep 1;112(5):1217-27. doi: 10.1152/jn.00353.2014. Epub 2014 Jun 11.
Learning to better discriminate a specific visual feature (i.e., a specific orientation in a specific region of space) has been associated with plasticity in early visual areas (sensory modulation) and with improvements in the transmission of sensory information from early visual areas to downstream sensorimotor and decision regions (enhanced readout). However, in many real-world scenarios that require perceptual expertise, observers need to efficiently process numerous exemplars from a broad stimulus class as opposed to just a single stimulus feature. Some previous data suggest that perceptual learning leads to highly specific neural modulations that support the discrimination of specific trained features. However, the extent to which perceptual learning acts to improve the discriminability of a broad class of stimuli via the modulation of sensory responses in human visual cortex remains largely unknown. Here, we used functional MRI and a multivariate analysis method to reconstruct orientation-selective response profiles based on activation patterns in the early visual cortex before and after subjects learned to discriminate small offsets in a set of grating stimuli that were rendered in one of nine possible orientations. Behavioral performance improved across 10 training sessions, and there was a training-related increase in the amplitude of orientation-selective response profiles in V1, V2, and V3 when orientation was task relevant compared with when it was task irrelevant. These results suggest that generalized perceptual learning can lead to modified responses in the early visual cortex in a manner that is suitable for supporting improved discriminability of stimuli drawn from a large set of exemplars.
学会更好地辨别特定视觉特征（即空间特定区域中的特定方向）与早期视觉区域的可塑性（感觉调制）以及从早期视觉区域到下游感觉运动和决策区域的感觉信息传递改善（增强读出）有关。然而，在许多需要感知专业知识的现实场景中，观察者需要有效地处理来自广泛刺激类别的大量示例，而不仅仅是单个刺激特征。先前的一些数据表明，感知学习会导致高度特定的神经调制，以支持对特定训练特征的辨别。然而，感知学习通过调节人类视觉皮层中的感觉反应来提高广泛刺激类别的可辨别性的程度在很大程度上仍然未知。在这里，我们使用功能磁共振成像和多变量分析方法，根据受试者在学会辨别以九种可能方向之一呈现的一组光栅刺激中的小偏移之前和之后早期视觉皮层中的激活模式，重建方向选择性反应曲线。在10次训练过程中，行为表现有所改善，与方向与任务无关时相比，当方向与任务相关时，V1、V2和V3中方向选择性反应曲线的幅度有与训练相关的增加。这些结果表明，广义感知学习可以以一种适合支持提高从大量示例中提取的刺激的可辨别性的方式，导致早期视觉皮层中的反应发生改变。
