Baddeley R, Abbott L F, Booth M C, Sengpiel F, Freeman T, Wakeman E A, Rolls E T
Department of Experimental Psychology, University of Oxford, UK.
Proc Biol Sci. 1997 Dec 22;264(1389):1775-83. doi: 10.1098/rspb.1997.0246.
The primary visual cortex (V1) is the first cortical area to receive visual input, and inferior temporal (IT) areas are among the last along the ventral visual pathway. We recorded, in area V1 of anaesthetized cats and area IT of awake macaque monkeys, responses of neurons to videos of natural scenes. Responses were analysed to test various hypotheses concerning the nature of neural coding in these two regions. A variety of spike-train statistics were measured including spike-count distributions, interspike interval distributions, coefficients of variation, power spectra, Fano factors and different sparseness measures. All statistics showed non-Poisson characteristics and several revealed self-similarity of the spike trains. Spike-count distributions were approximately exponential in both visual areas for eight different videos and for counting windows ranging from 50 ms to 5 seconds. The results suggest that the neurons maximize their information carrying capacity while maintaining a fixed long-term-average firing rate, or equivalently, minimize their average firing rate for a fixed information carrying capacity.
初级视觉皮层（V1）是第一个接收视觉输入的皮层区域，而颞下（IT）区域则位于腹侧视觉通路的最后阶段。我们在麻醉猫的V1区域和清醒猕猴的IT区域记录了神经元对自然场景视频的反应。对这些反应进行了分析，以检验关于这两个区域神经编码性质的各种假设。测量了各种脉冲序列统计量，包括脉冲计数分布、脉冲间隔分布、变异系数、功率谱、法诺因子和不同的稀疏度测量。所有统计量均显示出非泊松特征，并且有几个显示出脉冲序列的自相似性。对于八个不同的视频以及从50毫秒到5秒的计数窗口，两个视觉区域的脉冲计数分布均近似呈指数分布。结果表明，神经元在保持固定的长期平均放电率的同时最大化其信息承载能力，或者等效地，在固定的信息承载能力下最小化其平均放电率。
