SENSORIMOTOR INTEGRATION IN THE PRIMATE SUPERIOR COLLICULUS .2. COORDINATES OF AUDITORY SIGNALS
SENSORIMOTOR INTEGRATION IN THE PRIMATE SUPERIOR COLLICULUS .2. COORDINATES OF AUDITORY SIGNALS
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DOI：
10.1152/jn.1987.57.1.35
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发表时间：
1987-01-01
影响因子：
2.5
通讯作者：
SPARKS, DL
中科院分区：
文献类型：
--
作者：
JAY, MF;SPARKS, DL
基于前一篇论文的研究结果，已知听觉和视觉信号在上级丘（SC）水平被转换成共同的坐标，并且共享涉及扫视眼球运动的生成的运动回路。然而，目前尚不清楚感觉信号转化为运动坐标是否发生在SC之前或SC之内。也不知道在SC中观察到的听觉信号编码在什么坐标中。本实验测试了两个替代假设的参考框架的听觉信号中发现的更深层次的SC。假设听觉信号编码在头部坐标预测，与头部静止，听觉神经元的反应将不会受到影响的眼睛位置的变化，但将由声源的位置。听觉反应编码了眼睛运动轨迹的假设（运动误差）预测听觉细胞的反应将取决于声源的位置和眼睛在眼眶中的位置。当猴子在黑暗的房间中对听觉或视觉目标进行延迟扫视时，从SC中的神经元获得细胞外单单位记录。听觉信号的坐标是通过绘制听觉感受野来研究的，同时动物注视着沿水平面相隔沿着24度放置的三个目标中的一个。对于121个SC细胞中的99个，听觉感受野的空间位置被眼睛在眼眶中的位置显著改变。相比之下，下丘中分离的五个声敏细胞的反应不受眼睛位置变化的影响。与不同的固定位置相关的pinvertebra位置的系统变化可以解释这些发现的可能性，通过绘制听觉感受野来控制，而pinvertebra被机械限制。在这些条件下，眼睛在眼眶中的位置仍然对丘神经元对听觉刺激的反应性有显著影响。听觉感受野随眼睛位置变化的平均位移幅度（12.9度）与眼睛位置变化的幅度（24度）不一致。考虑了该结果的其他解释。一种可能性是，在SC内，存在从头部坐标中的听觉信号到运动误差坐标中的信号的逐渐过渡。（400字处截断摘要）
Based on the findings of the preceding paper, it is known that auditory and visual signals have been translated into common coordinates at the level of the superior colliculus (SC) and share a motor circuit involved in the generation of saccadic eye movements. It is not known, however, whether the translation of sensory signals into motor coordinates occurs prior to or within the SC. Nor is it known in what coordinates auditory signals observed in the SC are encoded. The present experiment tested two alternative hypotheses concerning the frame of reference of auditory signals found in the deeper layers of the SC. The hypothesis that auditory signals are encoded in head coordinates predicts that, with the head stationary, the response of auditory neurons will not be affected by variations in eye position but will be determined by the location of the sound source. The hypothesis that auditory responses encode the trajectory of the eye movement required to look to the target (motor error) predicts that the response of auditory cells will depend on both the position of the sound source and the position of the eyes in the orbit. Extracellular single-unit recordings were obtained from neurons in the SC while monkeys made delayed saccades to auditory or visual targets in a darkened room. The coordinates of auditory signals were studied by plotting auditory receptive fields while the animal fixated one of three targets placed 24 degrees apart along the horizontal plane. For 99 of 121 SC cells, the spatial location of the auditory receptive field was significantly altered by the position of the eyes in the orbit. In contrast, the responses of five sound-sensitive cells isolated in the inferior colliculus were not affected by variations in eye position. The possibility that systematic variations in the position of the pinnae associated with different fixation positions could account for these findings was controlled for by plotting auditory receptive fields while the pinnae were mechanically restrained. Under these conditions, the position of the eyes in the orbit still had a significant effect on the responsiveness of collicular neurons to auditory stimuli. The average magnitude of the shift of the auditory receptive field with changes in eye position (12.9 degrees) did not correspond to the magnitude of the shift in eye position (24 degrees). Alternative explanations for this finding were considered. One possibility is that, within the SC, there is a gradual transition from auditory signals in head coordinates to signals in motor error coordinates.(ABSTRACT TRUNCATED AT 400 WORDS)