State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, People's Republic of China.
IDG/McGovern Institute for Brain Research at BNU, Beijing Normal University, Beijing, People's Republic of China.
J Neurophysiol. 2021 Dec 1;126(6):2053-2064. doi: 10.1152/jn.00259.2021. Epub 2021 Nov 10.
The influence of internal brain state on behavioral performance is well illustrated by the gap saccade task, in which saccades might be initiated with short latency (express saccade) or with long latency (regular saccade) even though the external visual condition is identical. Accumulated evidence has demonstrated that the internal brain state is different before the initiation of an express saccade than a regular saccade. However, the reported origin of the fluctuation of internal brain state is disputed among previous studies, e.g., the fixation disengagement theory versus the oculomotor preparation theory. The present study examined these two theories by analyzing the rate and direction of fixational saccades, i.e., small amplitude saccades during fixation, because they could be modulated by the internal brain state. Since fixation disengagement is not spatially tuned, it might affect the rate but not the direction of fixational saccades. In contrast, oculomotor preparation can contain spatial information for the upcoming saccade and thus affect fixational saccade direction. We found that the different spatiotemporal characteristics of fixational saccades among tasks with different gap durations reveal diverse driving force to change the internal brain state. Under short gap duration (100 ms), fixation disengagement plays a primary role in switching internal brain states. Conversely, oculomotor preparation plays a primary role under medium (200 ms) and long (400 ms) gap durations. These results suggest that both fixation disengagement and oculomotor preparation can change the internal brain state, but their relative contributions are gap-duration dependent. While performing the gap saccade task, the role of fixation disengagement and oculomotor preparation in modulating the internal brain state is gap-duration dependent. Fixation disengagement plays a primary role when gap duration is shorter (100 ms), whereas oculomotor preparation plays a primary role when gap duration is longer (200 ms and 400 ms).
内部大脑状态对行为表现的影响在眼跳任务中得到了很好的说明，在该任务中，尽管外部视觉条件相同，但眼跳可能会以短潜伏期（快速眼跳）或长潜伏期（常规眼跳）开始。大量证据表明，在发起快速眼跳之前，内部大脑状态与常规眼跳不同。然而，在之前的研究中，关于内部大脑状态波动的起源存在争议，例如，固定脱离理论与眼动准备理论。本研究通过分析注视性眼跳的频率和方向，即注视期间的小幅度眼跳，来检验这两种理论，因为它们可以被内部大脑状态调制。由于固定脱离不是空间调谐的，它可能会影响注视性眼跳的频率，但不会影响其方向。相反，眼动准备可以包含即将到来的眼跳的空间信息，从而影响注视性眼跳的方向。我们发现，不同时长间隔任务中注视性眼跳的不同时空特征揭示了改变内部大脑状态的不同驱动力。在短间隔时长（100 毫秒）下，固定脱离在切换内部大脑状态中起主要作用。相反，在中等（200 毫秒）和长（400 毫秒）间隔时长下，眼动准备起主要作用。这些结果表明，固定脱离和眼动准备都可以改变内部大脑状态，但它们的相对贡献取决于间隔时长。在执行眼跳任务时，固定脱离和眼动准备在调节内部大脑状态方面的作用取决于间隔时长。当间隔时长较短（100 毫秒）时，固定脱离起主要作用，而当间隔时长较长（200 毫秒和 400 毫秒）时，眼动准备起主要作用。
Zotero 插件