Functional properties of single neurons in the face primary motor cortex of the primate. III. Relations with different directions of trained tongue protrusion.
Functional properties of single neurons in the face primary motor cortex of the primate. III. Relations with different directions of trained tongue protrusion.
复制标题
灵长类动物面部初级运动皮层单个神经元的功能特性。
作者：
G. M. Murray;B. Sessle
1. 在之前的论文中，我们提供的证据表明面部运动皮层在控制舌头运动中发挥着重要作用。面部运动皮层内许多位点的皮质内微刺激（ICMS）引起不同类型的舌头运动，这些“舌头-MI”位点的许多神经元接受口内机械敏感传入输入，它们的活动与猴子执行的舌头伸出任务有关。鉴于舌头运动期间各种舌头肌肉的协同作用，我们假设这些不同的舌头 MI 部位被招募来在舌头伸出运动期间影响舌头形状和位置的适当变化。该假设的预测是，舌头伸出运动方向的变化应该与不同舌头 MI 传出区内的活动变化相关。传出区活动的差异应反映在位于这些舌 MI 部位的神经元放电率的差异上。 2. 我们训练两只猴子在三个方向中的每一个方向执行伸出舌头的任务。舌突出任务传感器定位在距正中矢状面 0 度 (Ts)、向左 30 度 (Tlt) 或向右 30 度 (Trt) 处；后两种姿势被称为不对称舌头突出任务姿势。在舌头伸出任务试验期间，在上述两个或三个位置中的每一个位置处从舌头 MI 记录单个神经元。在咬合任务中也对一些神经元进行了研究。此外，还测试了神经元可能的机械敏感传入输入。 3. 在研究的 66 个神经元中，31 个（45%）表现出方向关系；也就是说，根据研究神经元活动的方向，每个神经元在预试验期（PTP）和伸舌任务的任务期之间的放电率变化显着不同。 4.“定向”神经元表现出单一优选的放电方向，因为在舌头伸出任务的一个方向期间的平均放电率显着大于任何其他方向。在舌头伸出任务的所有三个方向上研究的 20 个神经元中，18 个神经元中每一个的平均放电频率在其中一个不对称位置处最高，并且这 18 个神经元中的 12 个表现出从一个不对称任务方向到另一个不对称任务方向的绝对放电频率单调下降。 5. 当猴子执行咬人任务时，还研究了 13 个神经元。大多数舌 MI 定向神经元与咬合任务无关。（摘要截断为 400 字）
1. In previous papers we presented evidence pointing to an important role for face motor cortex in the control of tongue movements. Intracortical microstimulation (ICMS) at many sites within face motor cortex evoked different types of tongue movement, and many neurons at these "tongue-MI" sites received intraoral mechanosensitive afferent input, and their activity was related to a tongue-protrusion task performed by a monkey. In view of the synergistic action of the various tongue muscles during tongue movement, we hypothesized that these different tongue-MI sites are recruited to effect the appropriate change in tongue shape and position during a tongue-protrusion movement. A prediction from this hypothesis is that variations in the direction of a tongue-protrusion movement should be associated with variations in the activities within the different tongue-MI efferent zones. Differences in efferent-zone activity should be reflected in differences in the firing rates of neurons that are located at these tongue-MI sites. 2. We trained two monkeys to perform a tongue-protrusion task at each of three directions. The tongue-protrusion task transducer was positioned at 0 degrees (Ts), 30 degrees to the left (Tlt), or 30 degrees to the right (Trt) from the midsagittal plane; the latter two positions were termed asymmetric tongue-protrusion task positions. Single neurons were recorded from tongue-MI during trials of tongue-protrusion task at each of two or three of the above positions. Some of the neurons were also studied during a biting task. In addition, neurons were tested for possible mechanosensitive afferent input. 3. Of the 66 neurons studied, 31 (45%) exhibited directional relations; that is, the change in firing rate between the pretrial period (PTP) and the task period for the tongue-protrusion task was significantly different for each neuron depending on the direction in which the activity of the neuron was studied. 4. The "directional" neurons exhibited a single preferred direction of firing in that the mean firing rate during one direction of tongue-protrusion task was significantly greater than for any other direction. Of the 20 neurons studied at all three directions of tongue-protrusion task, the mean firing rate of each of 18 was highest at one of the asymmetric positions, and 12 of these 18 neurons exhibited a monotonic decrease in absolute firing frequency from one asymmetric task direction to the other. 5. Thirteen of the neurons were also studied while the monkey performed the biting task. Most tongue-MI directional neurons were not related to the biting task.(ABSTRACT TRUNCATED AT 400 WORDS)