Furmanski Christopher S, Schluppeck Denis, Engel Stephen A
HRL Laboratories, 3011 Malibu Canyon Road, Malibu, CA 90265, USA.
Curr Biol. 2004 Apr 6;14(7):573-8. doi: 10.1016/j.cub.2004.03.032.
Training can significantly improve performance on even the most basic visual tasks, such as detecting a faint patch of light or determining the orientation of a bar (for reviews, see ). The neural mechanisms of visual learning, however, remain controversial. One simple way to improve behavior is to increase the overall neural response to the trained stimulus by increasing the number or gain of responsive neurons. Learning of this type has been observed in other sensory modalities, where training increases the number of receptive fields that cover the trained stimulus. Here, we show that visual learning can selectively increase the overall response to trained stimuli in primary visual cortex (V1). We used functional magnetic resonance imaging (fMRI) to measure neural signals before and after one month of practice at detecting very low-contrast oriented patterns. Training increased V1 response for practiced orientations relative to control orientations by an average of 39%, and the magnitude of the change in V1 correlated moderately well with the magnitude of changes in detection performance. The elevation of V1 activity by training likely results from an increase in the number of neurons responding to the trained stimulus or an increase in response gain.
训练甚至能显著提高在最基本视觉任务上的表现，比如检测微弱的光斑或确定线条的方向（综述见 ）。然而，视觉学习的神经机制仍存在争议。一种改善行为的简单方法是通过增加反应神经元的数量或增益来增强对训练刺激的整体神经反应。在其他感觉模态中也观察到了这种类型的学习，在这些模态中，训练会增加覆盖训练刺激的感受野数量。在这里，我们表明视觉学习可以选择性地增强初级视觉皮层（V1）对训练刺激的整体反应。我们使用功能磁共振成像（fMRI）在检测极低对比度定向图案的一个月训练前后测量神经信号。相对于对照方向，训练使V1对训练方向的反应平均增加了39%，并且V1变化的幅度与检测性能变化的幅度中度相关。训练导致的V1活动增强可能是由于对训练刺激做出反应的神经元数量增加或反应增益增加。
