Kremers Jan, Kozyrev Vladislav, Silveira Luiz Carlos L, Kilavik Bjørg Elisabeth
Department of Experimental Ophthalmology, University of Tübingen Eye Hospital, Tübingen, Germany.
J Vis. 2004 Aug 9;4(7):643-63. doi: 10.1167/4.7.10.
The perception of flicker strength in a center stimulus can be affected by the presence of a surrounding stimulus. We correlated this effect with the interactions between centers and surrounds of the receptive fields (RFs) of neurons in the retino-geniculate pathways. The responses of cells in the lateral geniculate nucleus (LGN) of two New World monkey species, the common marmoset (Callithrix jacchus), and the owl monkey (Aotus azarae) were measured to two spatially non-overlapping sinusoidally modulating luminance stimuli of equal temporal frequency, one of which mainly stimulated the RF center, the other the RF surround. The relative temporal phase between the center and surround stimuli was varied. The response amplitude as a function of relative phase between the center and surround stimuli can be described by a simple model where the RF center and surround responses are vector-added. A minimal response was reached for stimuli in which the surround stimulus led the center stimulus, indicating that the RF surround response lagged the center response. The flicker strength in the center stimulus perceived by human observers was measured psychophysically. It was found that the perceived flicker strength could be described by the same function as was used for the cell data. There were qualitative similarities between the physiological and the psychophysical data, suggesting that the physiological basis of the psychophysically measured spatial interactions is present as early as the LGN. The data indicated the presence of a nonlinearity in center-surround interactions that is influenced by the stimulus contrast. The possible source of this nonlinearity was studied by comparing the center and the surround responses with those in which they were selectively stimulated.
中央刺激中闪烁强度的感知会受到周围刺激的影响。我们将这种效应与视网膜 - 膝状体通路中神经元感受野（RFs）的中央和周围之间的相互作用相关联。测量了两种新大陆猴物种，普通狨猴（Callithrix jacchus）和夜猴（Aotus azarae）的外侧膝状核（LGN）细胞对两个空间上不重叠、时间频率相等的正弦调制亮度刺激的反应，其中一个主要刺激RF中央，另一个刺激RF周围。中央和周围刺激之间的相对时间相位是变化的。中央和周围刺激之间的反应幅度作为相对相位的函数可以用一个简单模型来描述，其中RF中央和周围反应进行矢量相加。当周围刺激领先于中央刺激时，刺激达到最小反应，这表明RF周围反应滞后于中央反应。通过心理物理学方法测量了人类观察者所感知的中央刺激中的闪烁强度。发现所感知的闪烁强度可以用与细胞数据相同的函数来描述。生理数据和心理物理学数据之间存在定性相似性，这表明心理物理学测量的空间相互作用的生理基础早在LGN就已存在。数据表明中央 - 周围相互作用中存在受刺激对比度影响的非线性。通过将中央和周围反应与它们被选择性刺激时的反应进行比较，研究了这种非线性的可能来源。
