Department of Psychology, University of Minnesota Twin Cities, Minneapolis, Minnesota 55455
Department of Psychology, University of Minnesota Twin Cities, Minneapolis, Minnesota 55455.
J Neurosci. 2023 Dec 13;43(50):8777-8784. doi: 10.1523/JNEUROSCI.1325-23.2023.
During binocular rivalry, conflicting images are presented one to each eye and perception alternates stochastically between them. Despite stable percepts between alternations, modeling suggests that neural signals representing the two images change gradually, and that the duration of stable percepts are determined by the time required for these signals to reach a threshold that triggers an alternation. However, direct physiological evidence for such signals has been lacking. Here, we identify a neural signal in the human visual cortex that shows these predicted properties. We measured steady-state visual evoked potentials (SSVEPs) in 84 human participants (62 females, 22 males) who were presented with orthogonal gratings, one to each eye, flickering at different frequencies. Participants indicated their percept while EEG data were collected. The time courses of the SSVEP amplitudes at the two frequencies were then compared across different percept durations, within participants. For all durations, the amplitude of signals corresponding to the suppressed stimulus increased and the amplitude corresponding to the dominant stimulus decreased throughout the percept. Critically, longer percepts were characterized by more gradual increases in the suppressed signal and more gradual decreases of the dominant signal. Changes in signals were similar and rapid at the end of all percepts, presumably reflecting perceptual transitions. These features of the SSVEP time courses are well predicted by a model in which perceptual transitions are produced by the accumulation of noisy signals. Identification of this signal underlying binocular rivalry should allow strong tests of neural models of rivalry, bistable perception, and neural suppression. During binocular rivalry, two conflicting images are presented to the two eyes and perception alternates between them, with switches occurring at seemingly random times. Rivalry is an important and longstanding model system in neuroscience, used for understanding neural suppression, intrinsic neural dynamics, and even the neural correlates of consciousness. All models of rivalry propose that it depends on gradually changing neural activity that on reaching some threshold triggers the perceptual switches. This manuscript reports the first physiological measurement of neural signals with that set of properties in human participants. The signals, measured with EEG in human observers, closely match the predictions of recent models of rivalry, and should pave the way for much future work.
在双眼竞争中，两个相互冲突的图像分别呈现在两只眼睛中，感知在它们之间随机交替。尽管在交替之间存在稳定的感知，但建模表明，代表两个图像的神经信号会逐渐变化，并且稳定感知的持续时间取决于这些信号达到触发交替的阈值所需的时间。然而，直接的生理证据一直缺乏。在这里，我们在人类视觉皮层中发现了一种具有这些预测特性的神经信号。我们在 84 名人类参与者（62 名女性，22 名男性）中测量了稳态视觉诱发电位（SSVEP），他们的每只眼睛都呈现出正交的光栅，以不同的频率闪烁。参与者在收集 EEG 数据的同时报告他们的感知。然后，在参与者内部，比较了不同感知持续时间下两个频率的 SSVEP 幅度的时间历程。对于所有持续时间，在整个感知过程中，与被抑制刺激相对应的信号的幅度增加，而与主导刺激相对应的信号的幅度减小。关键是，较长的感知特征是被抑制信号的增加更渐进，主导信号的减少更渐进。在所有感知结束时，信号的变化相似且迅速，大概反映了感知的转变。SSVEP 时间历程的这些特征与一个模型很好地吻合，该模型认为感知的转变是由噪声信号的积累产生的。这种在双眼竞争下产生的信号的识别应该允许对竞争、双稳态感知和神经抑制的神经模型进行强有力的测试。在双眼竞争中，两个相互冲突的图像分别呈现在两只眼睛中，感知在它们之间交替，开关似乎在随机时间发生。竞争是神经科学中的一个重要且历史悠久的模型系统，用于理解神经抑制、内在神经动力学，甚至意识的神经相关性。所有竞争模型都提出，它取决于逐渐变化的神经活动，当达到某个阈值时，会触发感知开关。本手稿报告了在人类参与者中具有这些特性的神经信号的第一个生理测量。在人类观察者中使用 EEG 测量的信号与最近的竞争模型的预测非常吻合，并且应该为未来的许多工作铺平道路。
