Laboratorio de Neurociencia Cognitiva, Departamento de Psiquiatría, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
PLoS One. 2011 Apr 26;6(4):e19221. doi: 10.1371/journal.pone.0019221.
Humans and other animals change the way they perceive the world due to experience. This process has been labeled as perceptual learning, and implies that adult nervous systems can adaptively modify the way in which they process sensory stimulation. However, the mechanisms by which the brain modifies this capacity have not been sufficiently analyzed.
METHODOLOGY/PRINCIPAL FINDINGS: We studied the neural mechanisms of human perceptual learning by combining electroencephalographic (EEG) recordings of brain activity and the assessment of psychophysical performance during training in a visual search task. All participants improved their perceptual performance as reflected by an increase in sensitivity (d') and a decrease in reaction time. The EEG signal was acquired throughout the entire experiment revealing amplitude increments, specific and unspecific to the trained stimulus, in event-related potential (ERP) components N2pc and P3 respectively. P3 unspecific modification can be related to context or task-based learning, while N2pc may be reflecting a more specific attentional-related boosting of target detection. Moreover, bell and U-shaped profiles of oscillatory brain activity in gamma (30-60 Hz) and alpha (8-14 Hz) frequency bands may suggest the existence of two phases for learning acquisition, which can be understood as distinctive optimization mechanisms in stimulus processing.
CONCLUSIONS/SIGNIFICANCE: We conclude that there are reorganizations in several neural processes that contribute differently to perceptual learning in a visual search task. We propose an integrative model of neural activity reorganization, whereby perceptual learning takes place as a two-stage phenomenon including perceptual, attentional and contextual processes.
人类和其他动物由于经验而改变他们感知世界的方式。这个过程被标记为感知学习，意味着成年神经系统可以自适应地改变他们处理感官刺激的方式。然而，大脑改变这种能力的机制尚未得到充分分析。
方法/主要发现：我们通过结合脑电图（EEG）记录大脑活动和在视觉搜索任务中的训练期间的心理物理性能评估，研究了人类感知学习的神经机制。所有参与者都提高了他们的感知表现，表现为敏感性（d'）增加和反应时间减少。整个实验过程中都采集了 EEG 信号，揭示了与训练刺激特异性和非特异性相关的事件相关电位（ERP）成分 N2pc 和 P3 的幅度增加。P3 的非特异性修饰可能与上下文或基于任务的学习有关，而 N2pc 可能反映了对目标检测的更特定的注意力相关提升。此外，伽马（30-60Hz）和阿尔法（8-14Hz）频段的脑电活动的钟形和 U 形曲线可能表明学习获取存在两个阶段，这可以理解为刺激处理中独特的优化机制。
结论/意义：我们得出结论，在视觉搜索任务中，有几个神经过程的重新组织对感知学习有不同的贡献。我们提出了一个神经活动重组的综合模型，其中感知学习是一个两阶段的现象，包括感知、注意力和上下文过程。
