Wang Zhisong, Maier Alexander, Logothetis Nikos K, Liang Hualou
Microsoft Corporation, Bellevue, WA 98007 USA.
IEEE Trans Biomed Eng. 2009 Aug;56(8):2095-103. doi: 10.1109/TBME.2009.2018630. Epub 2009 Apr 7.
Bistable perception arises when an ambiguous stimulus under continuous view is perceived as an alternation of two mutually exclusive states. Such a stimulus provides a unique opportunity for understanding the neural basis of visual perception because it dissociates the perception from the visual input. In this paper, we focus on extracting the percept-related features from the local field potential (LFP) in monkey visual cortex for decoding its bistable structure-from-motion (SFM) perception. Our proposed feature extraction approach consists of two stages. First, we estimate and remove from each LFP trial the nonpercept-related stimulus-evoked activity via a local regression method called the locally weighted scatterplot smoothing because of the dissociation between the perception and the stimulus in our experimental paradigm. Second, we use the common spatial patterns approach to design spatial filters based on the residue signals of multiple channels to extract the percept-related features. We exploit a support vector machine (SVM) classifier on the extracted features to decode the reported perception on a single-trial basis. We apply the proposed approach to the multichannel intracortical LFP data collected from the middle temporal (MT) visual cortex in a macaque monkey performing an SFM task. We demonstrate that our approach is effective in extracting the discriminative features of the percept-related activity from LFP and achieves excellent decoding performance. We also find that the enhanced gamma band synchronization and reduced alpha and beta band desynchronization may be the underpinnings of the percept-related activity.
当在持续观察下一个模糊的刺激被感知为两个相互排斥状态的交替时，就会出现双稳态感知。这样的刺激为理解视觉感知的神经基础提供了一个独特的机会，因为它将感知与视觉输入分离开来。在本文中，我们专注于从猴子视觉皮层的局部场电位（LFP）中提取与感知相关的特征，以解码其双稳态结构从运动（SFM）感知。我们提出的特征提取方法包括两个阶段。首先，由于我们实验范式中感知与刺激之间的分离，我们通过一种称为局部加权散点图平滑的局部回归方法，从每个LFP试验中估计并去除与非感知相关的刺激诱发活动。其次，我们使用共同空间模式方法，基于多个通道的残留信号设计空间滤波器，以提取与感知相关的特征。我们在提取的特征上利用支持向量机（SVM）分类器在单试验基础上解码报告的感知。我们将提出的方法应用于从一只执行SFM任务的猕猴的颞中（MT）视觉皮层收集的多通道皮层内LFP数据。我们证明我们的方法在从LFP中提取与感知相关活动的判别特征方面是有效的，并实现了出色的解码性能。我们还发现增强的伽马波段同步以及减少的阿尔法和贝塔波段去同步可能是与感知相关活动的基础。
