Rizzolatti G, Gentilucci M, Camarda R M, Gallese V, Luppino G, Matelli M, Fogassi L
Istituto di Fisiologia Umana, Università di Parma, Italy.
Exp Brain Res. 1990;82(2):337-50. doi: 10.1007/BF00231253.
Single neurons were recorded from the rostral part of the agranular frontal cortex (area 6a beta) in awake, partially restrained macaque monkeys. In the medialmost and mesial sectors of this area, rostral to the supplementary motor area, neurons were found which were activated during arm reaching-grasping movements. These neurons ("reaching-grasping neurons") did not appear to be influenced by how the objects were grasped nor, with some exceptions, by where they were located. Their activity changed largely prior to the arm movement and continued until the end of it. The premovement modulation (excitatory or inhibitory) could start with stimulus presentation, with the saccade triggered by the stimulus or after stimulus fixation. The distance of the stimulus from the monkey was an important variable for activating many neurons. About half of the recorded neurons showed a modulation of the same sign during movement and premovement period. The other half showed an increase/decrease in activity which was of the opposite sign during movement and premovement period or part of it. In this last case the discharge changes were of the same sign when the stimulus was close to the monkey and when the monkey moved its arm to reach the objects, whereas they were of opposite sign when the stimulus was outside the animal's reach. Microstimulation of area 6a beta and the reconstruction of the locations of eye movement and arm movement related cells showed that the arm field was located more medially (and mesially) than the eye field described by Schlag and Schlag-Rey (1987). It is suggested that, unlike inferior area 6, which is mostly involved in selection of effectors on the basis of the physical properties of the objects and their spatial location (Rizzolatti and Gentilucci 1988), area 6a beta plays a role in the preparation of reaching-grasping arm movements and in their release when the appropriate conditions are set.
在清醒、部分受限的猕猴中，从无颗粒额叶皮质（6aβ区）的吻部记录单个神经元的活动。在该区域最内侧和中间部分，即补充运动区前方，发现了在手臂伸展-抓握运动期间被激活的神经元。这些神经元（“伸展-抓握神经元”）似乎不受抓握物体的方式影响，除了一些例外情况，也不受物体位置的影响。它们的活动在手臂运动之前就有很大变化，并持续到运动结束。运动前的调制（兴奋性或抑制性）可以在刺激呈现时开始，由刺激触发的扫视或刺激固定后开始。刺激与猴子之间的距离是激活许多神经元的一个重要变量。大约一半被记录的神经元在运动和运动前期表现出相同符号的调制。另一半神经元的活动在运动和运动前期或其中一部分表现出相反符号的增加/减少。在后一种情况下，当刺激靠近猴子且猴子移动手臂去够物体时，放电变化具有相同符号，而当刺激在动物可及范围之外时，放电变化具有相反符号。对6aβ区的微刺激以及与眼动和手臂运动相关细胞位置的重建表明，手臂区域比施拉格和施拉格-雷伊（1987年）所描述的眼动区域更靠内侧（和中间）。有人认为，与主要根据物体的物理特性及其空间位置来选择效应器的6区下部不同（里佐拉蒂和真蒂卢奇，1988年），6aβ区在准备伸展-抓握手臂运动以及在设定适当条件时释放这些运动方面发挥作用。
