Paradiso Michael A, MacEvoy Sean P, Huang Xin, Blau Seth
Department of Neuroscience, Brown University, Providence, RI 02912, USA.
Prog Brain Res. 2005;149:257-67. doi: 10.1016/S0079-6123(05)49018-4.
To conduct well-controlled studies of visual processing in the laboratory, deviations from natural visual situations must generally be employed. In some regards, the reduced visual paradigms typically used are adequate for providing an accurate description of visual representations. However, the use of fixation paradigms and stimuli isolated within a receptive field may underestimate the richness of visual processing in area V1. Experiments ranging from lightness encoding and perception to paradigms involving natural scenes and saccades used to examine the relationship between V1 activity and perception are reviewed in this chapter. Using more complex and natural visual stimulation, V1 responses have been detected that are significantly different from responses obtained in more reduced paradigms. A feature common to the findings of different experiments is that the scale of the activated neural population and circuitry appears to play a key role in the correlation between V1 activity and perception. More complex and natural visual stimulation brings into play extra-receptive field modulatory input not involved with stimulation localized to the receptive field. The results suggest that rather than subtly sculpting the response, modulatory input coming from intra- and/or intercortical sources is fundamental in establishing perceptual response patterns in natural visual situations.
为了在实验室中进行视觉处理的严格对照研究，通常必须采用与自然视觉情况不同的方式。在某些方面，典型使用的简化视觉范式足以准确描述视觉表征。然而，使用注视范式和在感受野内分离的刺激可能会低估V1区域视觉处理的丰富性。本章回顾了从明度编码与感知到涉及自然场景和扫视的范式等一系列实验，这些实验用于研究V1活动与感知之间的关系。使用更复杂和自然的视觉刺激时，检测到的V1反应与在更简化范式中获得的反应有显著差异。不同实验结果的一个共同特征是，激活的神经群体和神经回路的规模似乎在V1活动与感知之间的相关性中起关键作用。更复杂和自然的视觉刺激会引入与局限于感受野的刺激无关的额外感受野调制输入。结果表明，来自皮质内和/或皮质间源的调制输入并非微妙地塑造反应，而是在自然视觉情况下建立感知反应模式中起根本作用。
