Complex Movement Topography and Extrinsic Space Representation in the Rat Forelimb Motor Cortex as Defined by Long-Duration Intracortical Microstimulation
Complex Movement Topography and Extrinsic Space Representation in the Rat Forelimb Motor Cortex as Defined by Long-Duration Intracortical Microstimulation
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DOI：
10.1523/jneurosci.3454-12.2013
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发表时间：
2013-01-30
影响因子：
5.3
通讯作者：
Franchi, Gianfranco
中科院分区：
文献类型：
--
作者：
Bonazzi, Laura;Viaro, Riccardo;Franchi, Gianfranco
电刺激大鼠运动皮质可引起复杂的前肢多关节运动，包括肢体和爪子的运动。在这项研究中，这些运动通过位于手腕和中指(分别为肢体和爪子运动)的两个标记的3D位移和运动学变量来量化。用500ms的脉冲串对运动皮质进行微刺激。使用高分辨率的3D光学系统测量运动。根据其运动学描述了五种肢体运动(外展、内收、伸展、缩进、抬高)和四种爪动(张开、闭合、张开/闭合顺序、旋后)。这些运动类别的一致地形图被呈现在整个运动皮质上，以及爪子所指向的空间位置的地形图。在大约一半的皮质部位，确实存在一种特定的肢体-爪子运动组合模式。识别出四种类似行为曲目的肢体-爪子动作：伸展-成形、伸展-抓握顺序、带到身体和握住-样动作。总体而言，前肢运动区包括：(1)以伸展-成形运动表征为主的大的尾侧前肢区域；(2)包含伸展-抓握序列和带体运动表征的较小的吻部区域；(3)较外侧的部分，表现为握持式运动。这些结果支持这样的观点，即在大鼠中，运动皮质在相对复杂的水平上控制前肢运动，并提示复杂运动的有序表征及其动力学/运动学产生于前肢运动皮质组织的原理。
Electrical stimulation of the motor cortex in the rat can evoke complex forelimb multi-joint movements, including movement of limb and paw. In this study, these movements have been quantified in terms of 3D displacement and kinematic variables of two markers positioned on the wrist and middle digits (limb and paw movement, respectively). Electrical microstimulation was applied to the motor cortex using a pulse train of 500 ms duration. Movements were measured using a high-resolution 3D optical system. Five classes of limb movements (abduction, adduction, extension, retraction, elevation) and four classes of paw movements (opening, closure, opening/closure sequence, supination) were described according to their kinematics. A consistent topography of these classes of movements was presented across the motor cortex together with a topography of spatial locations to which the paw was directed. In about one-half of cortical sites, a specific pattern of limb-paw movement combination did exist. Four categories of limb-paw movements resembling behavioral repertoire were identified: reach-shaping, reach-grasp sequence, bring-to-body, and hold-like movement. Overall, the forelimb motor region included: (1) a large caudal forelimb area dominated by reach-shaping movement representation; (2) a small rostral area containing reach-grasp sequence and bring-to-body movement representation; and (3) a more lateral portion where hold-like movement was represented. These results support the view that, in rats, the motor cortex controls forelimb movements at a relatively complex level and suggest that the orderly representation of complex movements and their dynamics/kinematics emerge from the principles of forelimb motor cortex organization.