Temporal Limits of Visual Motion Processing: Psychophysics and Neurophysiology.
Temporal Limits of Visual Motion Processing: Psychophysics and Neurophysiology.
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DOI：
10.3390/vision3010005
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发表时间：
2019-01-26
期刊：
影响因子：
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通讯作者：
van de Grind, Wim A
中科院分区：
文献类型：
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作者：
Borghuis, Bart G;Tadin, Duje;van de Grind, Wim A
在最佳条件下，只要3-6毫秒的视觉刺激就足以让人类看到运动。在这个时间尺度上的运动感知意味着视觉系统在这些条件下以接近毫秒的精度可靠地编码、传输和处理神经信号。基于灵长类动物视网膜中运动信号的高时间精度的体外证据，我们研究了运动编码的神经元和感知限制之间的关系。具体来说，我们研究了猫视网膜神经节细胞在体内代表运动信息的时间尺度与人类运动识别的时间阈值之间的对应关系。神经节细胞编码运动的时间尺度为4.6 ~ 91 ms，与时间频率呈非线性关系，而与对比度无关。人类心理物理学表明，感知运动方向所需的最小刺激持续时间同样短暂，为5.6-65毫秒，同样取决于时间频率，但超过10%的时间与对比度无关。值得注意的是，尽管人类阈值和视网膜运动编码的最佳时间尺度存在20倍以上的差异，但生理和心理物理测量结果在整个过程中都密切相关（r = 0.99）。神经生理和心理物理数据的绝对值的匹配可以用来表明，从外侧膝状核（LGN）到感知水平的时间精度几乎没有损失。然而，我们也表明整合来自多个神经元的响应可以提高时间分辨率，并且这种空间和时间分辨率之间的潜在权衡将允许在LGN之后失去时间分辨率。虽然神经元整合的程度不能从我们的人类心理物理或神经生理学实验中确定，而且它对测量的时间分辨率的贡献是未知的，但我们的结果表明，在视网膜中建立的时间保真度和人类运动辨别的时间限制之间，刺激依赖具有惊人的相似性。
Under optimal conditions, just 3-6 ms of visual stimulation suffices for humans to see motion. Motion perception on this timescale implies that the visual system under these conditions reliably encodes, transmits, and processes neural signals with near-millisecond precision. Motivated by in vitro evidence for high temporal precision of motion signals in the primate retina, we investigated how neuronal and perceptual limits of motion encoding relate. Specifically, we examined the correspondence between the time scale at which cat retinal ganglion cells in vivo represent motion information and temporal thresholds for human motion discrimination. The timescale for motion encoding by ganglion cells ranged from 4.6 to 91 ms, and depended non-linearly on temporal frequency, but not on contrast. Human psychophysics revealed that minimal stimulus durations required for perceiving motion direction were similarly brief, 5.6-65 ms, and similarly depended on temporal frequency but, above ~10%, not on contrast. Notably, physiological and psychophysical measurements corresponded closely throughout (r = 0.99), despite more than a 20-fold variation in both human thresholds and optimal timescales for motion encoding in the retina. The match in absolute values of the neurophysiological and psychophysical data may be taken to indicate that from the lateral geniculate nucleus (LGN) through to the level of perception little temporal precision is lost. However, we also show that integrating responses from multiple neurons can improve temporal resolution, and this potential trade-off between spatial and temporal resolution would allow for loss of temporal resolution after the LGN. While the extent of neuronal integration cannot be determined from either our human psychophysical or neurophysiological experiments and its contribution to the measured temporal resolution is unknown, our results demonstrate a striking similarity in stimulus dependence between the temporal fidelity established in the retina and the temporal limits of human motion discrimination.