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首页> 外文期刊>The European Journal of Neuroscience >The role of the dorsal thalamus in visual processing and object selection: A case of an attentional system in amphibians
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The role of the dorsal thalamus in visual processing and object selection: A case of an attentional system in amphibians

机译：丘脑背面在视觉处理和对象选择中的作用：两栖动物注意系统的案例

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In amphibians, the midbrain tectum is regarded as the visual centre for object recognition but the functional role of forebrain centres in visual information processing is less clear. In order to address this question, the dorsal thalamus was lesioned in the salamander Plethodon shermani, and the effects on orienting behaviour or on visual processing in the tectum were investigated. In a two-alternative-choice task, the average number of orienting responses toward one of two competing prey or simple configural stimuli was significantly decreased in lesioned animals compared to that of controls and sham-lesioned animals. When stimuli were presented during recording from tectal neurons, the number of spikes on presentation of a stimulus in the excitatory receptive field and a second salient stimulus in the surround was significantly reduced in controls and sham-lesioned salamanders compared to single presentation of the stimulus in the excitatory receptive field, while this inhibitory effect on the number of spikes of tectal neurons was absent in thalamus-lesioned animals. In amphibians, the dorsal thalamus is part of the second visual pathway which extends from the tectum via the thalamus to the telencephalon. A feedback loop to the tectum is assumed to modulate visual processing in the tectum and to ensure orienting behaviour toward visual objects. It is concluded that the tectum-thalamus-telencephalon pathway contributes to the recognition and evaluation of objects and enables spatial attention in object selection. This attentional system in amphibians resembles that found in mammals and illustrates the essential role of attention for goal-directed visuomotor action. Lesions of the dorsal thalamus affected both the visuomotor behavior toward salient prey-like stimuli and the responses of visual neurons to these stimuli in the midbrain tectum of a salamander. The visual ascending pathways in amphibians essentially contribute to visual spatial attention as in mammals. Our findings support the view that cognitive abilities develop gradually along evolutionary lines.
机译：在两栖动物中，中脑盖被视为对象识别的视觉中心，但前脑中心在视觉信息处理中的功能作用尚不清楚。为了解决这个问题，在thPlethodon shermani中损害了背丘脑，并研究了其对定向行为或对顶盖视觉加工的影响。在两种选择的任务中，与对照组和假动物相比，患病动物对两种竞争猎物或简单构型刺激之一的定向反应的平均数量明显减少。当在记录期间从顶盖神经元中出现刺激时，与对照组中的单次刺激相比，在对照组和假病变sal中，在刺激性感受野中出现刺激时出现尖峰的次数和在周围环境中出现的第二次显着刺激时的数目明显减少。兴奋性感受野，而对丘脑病变动物没有这种对顶盖神经元突波数量的抑制作用。在两栖动物中，背侧丘脑是第二视觉路径的一部分，该路径从大脑皮层经丘脑延伸至端脑。假设到了顶盖的反馈回路来调节顶盖中的视觉处理并确保朝向视觉对象的定向行为。结论是，丘脑-丘脑-脑脑通路有助于物体的识别和评估，并在物体选择中引起空间注意。两栖动物中的这种注意力系统类似于在哺乳动物中发现的系统，并且说明了注意力对于目标定向的视觉运动动作的基本作用。丘脑背丘的病变既影响对sal突类刺激的可见运动行为，也影响affected在中脑顶盖中视觉神经元对这些刺激的反应。两栖动物中的视觉上升途径与哺乳动物一样，实质上有助于视觉空间注意。我们的发现支持这样一种观点，即认知能力沿着进化路线逐渐发展。

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