Parwaga Sandeep, Buckley David, Duke Philip A
J Vis. 2016;16(3):11. doi: 10.1167/16.3.11.
We perceive a stable visual world, which enables successful interaction with our environment, despite movements of the eyes, head, and body. How are such perceptions formed? One possibility is that retino-centric visual input is transformed into representations at higher levels, such as head-, body-, or world-centered representations. We investigated this hypothesis using the tilt aftereffect in a balanced adaptation paradigm designed to isolate head-, body-, and world-centered aftereffects. Observers adapted to two oppositely tilted stimuli, each contingent on one of two different gaze, head, or body directions. We found aftereffects contingent on gaze direction, but not head or body direction. This demonstrates that adaptable tilt representations exist in a head-centric frame but not in higher reference frames. These aftereffects may be attributed to adaptation of retinotopic tilt-sensitive neurons whose responses are modulated by gaze direction (gain fields). Such neurons could support functionally head-centric tilt representations and are found as early as V1. On the basis of our results we would not expect activity in tilt-sensitive neurons to be modulated by head or body direction. The balanced adaptation paradigm is a useful tool for examining properties of the process responsible for gaze modulation of activity in visual neurons.
尽管眼睛、头部和身体会运动，但我们仍能感知到一个稳定的视觉世界，这使得我们能够与周围环境进行成功互动。这种感知是如何形成的呢？一种可能性是，以视网膜为中心的视觉输入会在更高层次上转化为表征，比如以头部、身体或世界为中心的表征。我们使用倾斜后效，在一个经过平衡的适应范式中对此假设进行了研究，该范式旨在分离以头部、身体和世界为中心的后效。观察者适应了两个方向相反的倾斜刺激，每个刺激都取决于两种不同的注视、头部或身体方向之一。我们发现了取决于注视方向的后效，但没有发现取决于头部或身体方向的后效。这表明适应性倾斜表征存在于以头部为中心的框架中，而不存在于更高的参考框架中。这些后效可能归因于视网膜拓扑倾斜敏感神经元的适应，其反应受注视方向（增益场）调制。这样的神经元可以支持功能性的以头部为中心的倾斜表征，并且最早在V1区就能发现。基于我们的研究结果，我们预计倾斜敏感神经元的活动不会受到头部或身体方向的调制。平衡适应范式是研究负责视觉神经元活动注视调制过程特性的有用工具。
