PDF(Pubmed)
Abstract：
UNASSIGNED: The ramp aftereffect, a visual phenomenon in which perception of light changes dynamically after exposure to sawtooth-modulated light, was first described in 1967. Despite decades of psychophysical research, location and mechanisms of its generation remain unknown. In this study, we investigated a potential retinal contribution to effect formation with specific emphasis on on-/off-pathway involvement.
UNASSIGNED: A 100 ms flash electroretinogram (ERG) was employed to probe the adaptive state of retinal neurons after presentation of stimuli that were homogenous in space but modulated in time following a sawtooth pattern (upward or downward ramps at 2 Hz). Additionally, a psychophysical nulling experiment was performed.
UNASSIGNED: Psychophysics data confirmed previous findings that the ramp aftereffect opposes the adapting stimuli in ramp direction and is stronger after upward ramps. The ERG study revealed significant changes of activity in every response component in the low-frequency range (a-wave, b-wave, on-PhNR, d-wave and off-PhNR) and high-frequency range (oscillatory potentials) in amplitudes, peak times, or both. The changes are neither specific to the on- or off-response nor antagonistic between ramp directions. With downward ramp adaptation, effects were stronger. Neither amplitudes nor peak times were correlated with perception strength. Amplitudes and peak times were uncorrelated, and the effect diminished over time, ceasing almost completely with three seconds.
UNASSIGNED: Despite abundant effects on retinal responses, the pattern of adaptational effects was not specific to the sawtooth nature of adaptation. Although not ruling out retinal contributions the present findings favor post-retinal mechanisms as the primary locus of the ramp aftereffect.
UNASSIGNED: A 100 ms flash electroretinogram (ERG) was employed to probe the adaptive state of retinal neurons after presentation of stimuli that were homogenous in space but modulated in time following a sawtooth pattern (upward or downward ramps at 2 Hz). Additionally, a psychophysical nulling experiment was performed.
UNASSIGNED: Psychophysics data confirmed previous findings that the ramp aftereffect opposes the adapting stimuli in ramp direction and is stronger after upward ramps. The ERG study revealed significant changes of activity in every response component in the low-frequency range (a-wave, b-wave, on-PhNR, d-wave and off-PhNR) and high-frequency range (oscillatory potentials) in amplitudes, peak times, or both. The changes are neither specific to the on- or off-response nor antagonistic between ramp directions. With downward ramp adaptation, effects were stronger. Neither amplitudes nor peak times were correlated with perception strength. Amplitudes and peak times were uncorrelated, and the effect diminished over time, ceasing almost completely with three seconds.
UNASSIGNED: Despite abundant effects on retinal responses, the pattern of adaptational effects was not specific to the sawtooth nature of adaptation. Although not ruling out retinal contributions the present findings favor post-retinal mechanisms as the primary locus of the ramp aftereffect.
摘要：
■坡道后效应，一种视觉现象，其中光的感知在暴露于锯齿调制光后动态变化，最早描述于1967年。尽管进行了数十年的心理物理学研究，其产生的位置和机制仍然未知。在这项研究中,我们研究了视网膜对效应形成的潜在贡献,特别强调通路上/外的参与.
■使用100ms的闪光视网膜电图（ERG）来探测视网膜神经元在空间上均匀但遵循锯齿模式（向上或向下的斜坡在2Hz下）在时间上调制的刺激后的适应状态。此外,进行了心理物理归零实验。
■心理物理学数据证实了先前的发现，即斜坡后效在斜坡方向上与适应刺激相反，并且在上升斜坡后更强。ERG研究揭示了低频范围内每个响应分量的活动的显着变化（a波，b波,在PhNR上，d波和关PhNR）和高频范围（振荡电位）的振幅，高峰时间,或者两者兼而有之。这些变化既不是特定于接通或断开响应，也不是斜坡方向之间的拮抗作用。随着向下倾斜的适应，效果更强。振幅和峰值时间都与感知强度无关。振幅和峰值时间不相关，效果随着时间的推移而减弱，几乎在三秒钟内完全停止。
■尽管对视网膜反应有丰富的影响，适应效应的模式并不局限于适应的锯齿性质。尽管不排除视网膜的贡献，但目前的发现倾向于视网膜后机制作为斜坡后效应的主要部位。
■使用100ms的闪光视网膜电图（ERG）来探测视网膜神经元在空间上均匀但遵循锯齿模式（向上或向下的斜坡在2Hz下）在时间上调制的刺激后的适应状态。此外,进行了心理物理归零实验。
■心理物理学数据证实了先前的发现，即斜坡后效在斜坡方向上与适应刺激相反，并且在上升斜坡后更强。ERG研究揭示了低频范围内每个响应分量的活动的显着变化（a波，b波,在PhNR上，d波和关PhNR）和高频范围（振荡电位）的振幅，高峰时间,或者两者兼而有之。这些变化既不是特定于接通或断开响应，也不是斜坡方向之间的拮抗作用。随着向下倾斜的适应，效果更强。振幅和峰值时间都与感知强度无关。振幅和峰值时间不相关，效果随着时间的推移而减弱，几乎在三秒钟内完全停止。
■尽管对视网膜反应有丰富的影响，适应效应的模式并不局限于适应的锯齿性质。尽管不排除视网膜的贡献，但目前的发现倾向于视网膜后机制作为斜坡后效应的主要部位。
