Department of Physiology, Anatomy and Cellular Biology, Division of Neurosciences, Pablo de Olavide University, 41013, Seville, Spain.
Sci Rep. 2021 Aug 17;11(1):16701. doi: 10.1038/s41598-021-96153-6.
The eyelid motor system has been used for years as an experimental model for studying the neuronal mechanisms underlying motor and cognitive learning, mainly with classical conditioning procedures. Nonetheless, it is not known yet which brain structures, or neuronal mechanisms, are responsible for the acquisition, storage, and expression of these motor responses. Here, we studied the temporal correlation between unitary activities of identified eyelid and vibrissae motor cortex neurons and the electromyographic activity of the orbicularis oculi and vibrissae muscles and magnetically recorded eyelid positions during classical conditioning of eyelid and vibrissae responses, using both delay and trace conditioning paradigms in behaving mice. We also studied the involvement of motor cortex neurons in reflexively evoked eyelid responses and the kinematics and oscillatory properties of eyelid movements evoked by motor cortex microstimulation. Results show the involvement of the motor cortex in the performance of conditioned responses elicited during the classical conditioning task. However, a timing correlation analysis showed that both electromyographic activities preceded the firing of motor cortex neurons, which must therefore be related more with the reinforcement and/or proper performance of the conditioned responses than with their acquisition and storage.
眼睑运动系统多年来一直被用作研究运动和认知学习的神经元机制的实验模型，主要采用经典条件作用程序。然而，目前尚不清楚是哪些脑结构或神经元机制负责这些运动反应的获得、存储和表达。在这里，我们研究了在行为小鼠中进行眼睑和触须反应的经典条件作用过程中，已识别的眼睑和触须运动皮层神经元的单元活动与眼轮匝肌和触须肌的肌电图活动以及磁记录的眼睑位置之间的时间相关性，使用了延迟和痕迹条件作用范式。我们还研究了运动皮层神经元在反射性诱发的眼睑反应中的参与程度，以及运动皮层微刺激诱发的眼睑运动的运动学和振荡特性。结果表明，运动皮层参与了在经典条件作用任务中引发的条件反应的表现。然而，时相关分析表明，肌电图活动都先于运动皮层神经元的放电，因此，这些神经元必然与条件反应的强化和/或正确表现有关，而不是与它们的获得和存储有关。
