Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
IEEE Trans Biomed Eng. 2011 Jul;58(7):1884-90. doi: 10.1109/TBME.2010.2095854. Epub 2010 Dec 3.
A major challenge for cognitive scientists is to deduce and explain the neural mechanisms of the rapid transposition between stimulus energy and recalled memory-between the specific (sensation) and the generic (perception)-in both material and mental aspects. Researchers are attempting three explanations in terms of neural codes. The microscopic code: cellular neurobiologists correlate stimulus properties with the rates and frequencies of trains of action potentials induced by stimuli and carried by topologically organized axons. The mesoscopic code: cognitive scientists formulate symbolic codes in trains of action potentials from feature-detector neurons of phonemes, lines, odorants, vibrations, faces, etc., that object-detector neurons bind into representations of stimuli. The macroscopic code: neurodynamicists extract neural correlates of stimuli and associated behaviors in spatial patterns of oscillatory fields of dendritic activity, which self-organize and evolve on trajectories through high-dimensional brain state space. This multivariate code is expressed in landscapes of chaotic attractors. Unlike other scientific codes, such as DNA and the periodic table, these neural codes have no alphabet or syntax. They are epistemological metaphors that experimentalists need to measure neural activity and engineers need to model brain functions. My aim is to describe the main properties of the macroscopic code and the grand challenge it poses: how do very large patterns of textured synchronized oscillations form in cortex so quickly?
认知科学家面临的一个主要挑战是推断和解释刺激能量与回忆记忆之间的快速转换的神经机制——在物质和精神方面的具体（感觉）和通用（感知）之间。研究人员正在尝试用三种神经编码来解释。微观代码：细胞神经生物学家将刺激特性与刺激引起的动作电位的速率和频率相关联，这些动作电位由拓扑组织的轴突携带。中观代码：认知科学家从语音、线条、气味、振动、面部等特征探测器神经元的动作电位序列中制定符号代码，而目标探测器神经元将这些代码绑定到刺激的表示中。宏观代码：神经动力学家从树突活动的振荡场的空间模式中提取刺激和相关行为的神经相关物，这些振荡场在通过高维脑状态空间的轨迹上自我组织和进化。这个多变量代码在混沌吸引子的景观中得到表达。与 DNA 和元素周期表等其他科学代码不同，这些神经代码没有字母表或语法。它们是认识论隐喻，实验人员需要测量神经活动，工程师需要模拟大脑功能。我的目标是描述宏观代码的主要特性及其带来的巨大挑战：如此快速地在皮层中形成如此大的纹理同步振荡模式是如何实现的？
