Cue Reliability and a Landmark Stability Heuristic Determine Relative Weighting Between Egocentric and Allocentric Visual Information in Memory-Guided Reach
Cue Reliability and a Landmark Stability Heuristic Determine Relative Weighting Between Egocentric and Allocentric Visual Information in Memory-Guided Reach
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DOI：
10.1152/jn.01008.2009
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发表时间：
2010-06-01
影响因子：
2.5
通讯作者：
Crawford, J. Douglas
中科院分区：
文献类型：
--
作者：
Byrne, Patrick A.;Crawford, J. Douglas
目前还不知道自我中心的视觉信息（目标相对于自我的位置）和非自我中心的视觉信息（目标相对于外部地标的位置）是如何整合形成到达计划的。基于啮齿动物和人类的行为数据，我们假设视觉地标的稳定程度会影响相对权重。此外，基于大量的线索组合研究，我们假设，达到系统将像一个最大似然估计（MLE），其中两个线索的可靠性决定其相对权重。为了预测这些因素可能如何相互作用，我们开发了一个MLE模型，该模型根据各自的可靠性来衡量自我中心和以他人为中心的信息，并且还基于额外的稳定性启发式。我们在10名人类受试者中通过操纵地标的稳定性和可靠性来测试该模型的预测在三个到达触摸任务中（通过地标的可变幅度振动和可变幅度注视移位）：自我中心控制（在没有地标的情况下到达）、非自我中心控制（相对于地标到达）和线索冲突任务（涉及记忆间隔期间的微妙地标“移位”）。从所有三个实验的变异性被用来推导参数的MLE模型，然后被用来模拟自我中心，allocentric加权的线索冲突实验。正如该模型预测的那样，地标振动，尽管它缺乏指向变异性（从而allocentric可靠性）在控制实验的影响，有很强的自我中心，allocentric加权的影响。没有稳定性启发式的简化模型无法重现这种效果。这些结果表明，在记忆引导的到达过程中，外部线索稳定性的分析至少和确定线索权重的可靠性一样重要。
It is not known how egocentric visual information ( location of a target relative to the self) and allocentric visual information ( location of a target relative to external landmarks) are integrated to form reach plans. Based on behavioral data from rodents and humans we hypothesized that the degree of stability in visual landmarks would influence the relative weighting. Furthermore, based on numerous cue-combination studies we hypothesized that the reach system would act like a maximum-likelihood estimator (MLE), where the reliability of both cues determines their relative weighting. To predict how these factors might interact we developed an MLE model that weighs egocentric and allocentric information based on their respective reliabilities, and also on an additional stability heuristic. We tested the predictions of this model in 10 human subjects by manipulating landmark stability and reliability ( via variable amplitude vibration of the landmarks and variable amplitude gaze shifts) in three reach-to-touch tasks: an egocentric control ( reaching without landmarks), an allocentric control ( reaching relative to landmarks), and a cue-conflict task ( involving a subtle landmark "shift" during the memory interval). Variability from all three experiments was used to derive parameters for the MLE model, which was then used to simulate egocentric-allocentric weighting in the cue-conflict experiment. As predicted by the model, landmark vibration-despite its lack of influence on pointing variability ( and thus allocentric reliability) in the control experiment-had a strong influence on egocentric-allocentric weighting. A reduced model without the stability heuristic was unable to reproduce this effect. These results suggest heuristics for extrinsic cue stability are at least as important as reliability for determining cue weighting in memory-guided reaching.