Jay M F, Sparks D L
Nature. 1984;309(5966):345-7. doi: 10.1038/309345a0.
The process by which sensory signals are transformed into commands for the control of movement is poorly understood. A potential site for such a transformation is the superior colliculus (SC), which receives auditory, visual and somatosensory inputs and contains neurones that discharge before saccadic eye movements. Along the primary sensory pathways, signals coding the spatial location of auditory, visual and somatosensory targets are based on distinctly different coordinate systems, and it is not known whether each type of sensory input uses a separate motor pathway or if they are converted into a common coordinate system in order to share a single pre-motor circuit. Sensory neurones in the SC have spatially restricted receptive fields (RFs) and are organized into maps across the collicular surface. Acute experiments have shown a rough correspondence between the spatial positions of RFs of neurones encountered along a single dorsal-ventral penetration of the colliculus, regardless of the modality of the effective stimulus, suggesting that auditory, visual and somatosensory maps might be in register. However, in these conditions the head-centred auditory system and the retinotopic visual system are aligned because the eyes are in the primary orbital position. Moreover, other data have suggested that the primate SC is organized in motor, not sensory, coordinates, although in the cat, eye position was found to have no effect on auditory receptive fields. We therefore sought here to determine what happens to the registration of the auditory and visual maps in the alert, behaving animal. Monkeys, with heads fixed, were trained to make delayed saccadic eye movements to auditory or visual targets from one of three initial fixation points while the activity of single neurones was recorded extracellularly. We found that the auditory receptive fields shifted with changes in eye position, allowing the auditory and visual maps to remain in register.
感觉信号转化为运动控制指令的过程目前还知之甚少。这种转化的一个潜在部位是上丘（SC），它接收听觉、视觉和躯体感觉输入，并包含在眼球快速运动之前放电的神经元。在主要的感觉通路中，编码听觉、视觉和躯体感觉目标空间位置的信号基于截然不同的坐标系，目前尚不清楚每种感觉输入是使用单独的运动通路，还是它们被转换为一个共同的坐标系以便共享一个单一的运动前回路。上丘中的感觉神经元具有空间受限的感受野（RFs），并在整个丘表面组织成图谱。急性实验表明，沿着丘的单个背腹穿透所遇到的神经元的RFs的空间位置之间存在大致对应关系，而与有效刺激的模式无关，这表明听觉、视觉和躯体感觉图谱可能是对齐的。然而，在这些条件下，以头部为中心的听觉系统和视网膜拓扑视觉系统是对齐的，因为眼睛处于初始眼眶位置。此外，其他数据表明，灵长类动物的上丘是以运动而非感觉坐标组织的，尽管在猫中，发现眼位对听觉感受野没有影响。因此，我们在此试图确定在警觉的行为动物中听觉和视觉图谱的对齐会发生什么。头部固定的猴子被训练从三个初始注视点之一对听觉或视觉目标进行延迟的眼球快速运动，同时细胞外记录单个神经元的活动。我们发现听觉感受野随着眼位的变化而移动，从而使听觉和视觉图谱保持对齐。
