Kang Incheol, Malpeli Joseph G
Neuroscience Program, University of Illinois, Champaign, Illinois 61820, USA.
J Neurophysiol. 2009 Aug;102(2):841-52. doi: 10.1152/jn.90642.2008. Epub 2009 May 20.
Contrast thresholds of cells in the dorsal lateral geniculate (LGNd) and medial interlaminar (MIN) nuclei of awake cats were measured for scotopic and mesopic vision with drifting sine gratings (1/8, 2, and 4 cycles/deg [cpd]; 4-Hz temporal frequency). Thresholds for mean firing rate (F0) and temporally modulated responses (F1) were derived with receiver-operating-characteristic analyses and compared with behavioral measures recently reported by Kang and colleagues. Behavioral sensitivity was predicted by the neural responses of the most sensitive combinations of cell class and response mode: Y-cell F1 responses for 1/8 cpd, X-cell F1 responses for 2 cpd, and Y-cell F0 responses for 4 cpd. All previous estimates of neural scotopic increment thresholds in animal models fell between Weber's law (proportional to retinal illuminance) and the deVries-Rose law (proportional to the square root of illuminance). However, psychophysical experiments suggest that under appropriate conditions human scotopic vision follows the deVries-Rose law. If behavioral sensitivity is assumed to be determined by the most sensitive class of cells, this discrepancy is resolved. Under scotopic conditions, off-center Y cells were the most sensitive and these followed the deVries-Rose law fairly closely. MIN Y cells were, on average, 0.25 log units more sensitive than LGNd Y cells under scotopic conditions, supporting a previous proposal that the MIN is a specialization of the carnivore for dim-light vision. We conclude that both physiologically and behaviorally, cat and human scotopic vision are fundamentally similar, including adherence to the deVries-Rose law for detection of Gabor functions.
使用漂移正弦光栅（1/8、2和4周/度[cpd]；4赫兹时间频率），测量清醒猫的背外侧膝状体（LGNd）和内侧层间核（MIN）中细胞在暗视觉和中间视觉下的对比度阈值。通过接收者操作特征分析得出平均放电率（F0）和时间调制反应（F1）的阈值，并与Kang及其同事最近报告的行为测量结果进行比较。行为敏感性由细胞类别和反应模式的最敏感组合的神经反应预测：1/8 cpd时的Y细胞F1反应、2 cpd时的X细胞F1反应以及4 cpd时的Y细胞F0反应。动物模型中神经暗视觉增量阈值的所有先前估计值都介于韦伯定律（与视网膜照度成正比）和德弗里斯 - 罗斯定律（与照度的平方根成正比）之间。然而，心理物理学实验表明，在适当条件下人类暗视觉遵循德弗里斯 - 罗斯定律。如果假设行为敏感性由最敏感的细胞类别决定，那么这种差异就得到了解决。在暗视觉条件下，偏心Y细胞最敏感，并且它们相当紧密地遵循德弗里斯 - 罗斯定律。在暗视觉条件下，MIN Y细胞平均比LGNd Y细胞敏感0.25对数单位，支持了先前的提议，即MIN是食肉动物用于暗光视觉的特化结构。我们得出结论，在生理和行为上，猫和人类的暗视觉在根本上是相似的，包括在检测伽柏函数时遵循德弗里斯 - 罗斯定律。
