Sektion Neurophysiologie, Universität Ulm, Albert Einstein Allee 47, 89081 Ulm, Germany.
Exp Brain Res. 2011 Dec;215(3-4):327-44. doi: 10.1007/s00221-011-2900-z. Epub 2011 Oct 18.
We investigated the relative weighting of vestibular, optokinetic and podokinetic (foot and leg proprioceptive) cues for the perception of self-turning in an environment which was either stationary (concordant stimulation) or moving (discordant stimulation) and asked whether cue weighting changes if subjects (Ss) detect a discordance. Ss (N = 18) stood on a turntable inside an optokinetic drum and turned either passively (turntable rotating) or actively in space at constant velocities of 15, 30, or 60°/s. Sensory discordance was introduced by simultaneous rotations of the environment (drum and/or turntable) at ±{5, 10, 20, 40, 80}% of self-turning velocity. In one experiment, Ss were to detect these rotations (i.e. the sensory discordance), and in a second experiment they reported perceived angular self-displacement. Discordant optokinetic cues were better detected, and more heavily weighted for self-turning perception, than discordant podokinetic cues. Within Ss, weights did not depend on whether a discordance was detected or not. Across Ss, optokinetic weights varied over a large range and were negatively correlated with the detection scores: the more perception was influenced by discordant optokinetic cues, the poorer was the detection score; no such correlation was found among the podokinetic results. These results are interpreted in terms of a "self-referential" model that makes the following assumptions: (1) a weighted average of the available sensory cues both determines turning perception and serves as a reference to which the optokinetic cue is compared; (2) a discordance is detected if the difference between reference and optokinetic cue exceeds some threshold; (3) the threshold value corresponds to about the same multiple of sensory uncertainty in all Ss. With these assumptions the model explains the observed relation between optokinetic weight and detection score.
我们研究了在环境中自我转身时，前庭、视动和动觉（脚和腿部本体感觉）线索的相对权重，环境要么是静止的（一致刺激），要么是运动的（不一致刺激），并询问如果受试者（Ss）检测到不和谐，线索权重是否会发生变化。Ss（N=18）站在视动鼓内的转台上，以 15、30 或 60°/s 的恒定速度被动（转台旋转）或主动在空间中旋转。通过同时以±{5、10、20、40、80}%的自我旋转速度旋转环境（鼓和/或转台）引入感觉不和谐。在一个实验中，Ss 被要求检测这些旋转（即感觉不和谐），而在第二个实验中，他们报告感知到的角度自我位移。与动觉线索相比，不和谐的视动线索更容易被检测到，并且在自我旋转感知中权重更大。在 Ss 内部，权重不取决于是否检测到不和谐。在 Ss 之间，视动权重变化范围很大，并且与检测分数呈负相关：受不和谐视动线索影响越大，检测分数越低；在动觉结果中没有发现这种相关性。这些结果可以根据“自我参照”模型进行解释，该模型做出了以下假设：（1）可用感觉线索的加权平均值既决定了旋转感知，又作为参考，与视动线索进行比较；（2）如果参考和视动线索之间的差异超过某个阈值，则会检测到不和谐；（3）阈值值对应于所有 Ss 中感觉不确定性的相同倍数。有了这些假设，该模型解释了观察到的视动权重与检测分数之间的关系。
