Neurorehabilitation Unit, Lille University Medical Center, 59000 Lille, France; Inserm U1171, University Lille, Degenerative and Vascular Cognitive Disorders, 59000 Lille, France.
Department of Clinical Neurophysiology, Lille University Medical Center, 59000 Lille, France; ULCO, URePSSS unité de recherche pluridisciplinaire sport santé société (EA7369), 62228 Calais, France.
Neurophysiol Clin. 2019 Apr;49(2):115-123. doi: 10.1016/j.neucli.2018.12.005. Epub 2018 Dec 29.
Parietofrontal (PF) networks link the posterior parietal cortex to premotor and prefrontal areas, and are involved in the control of many motor and cognitive behaviors in healthy humans. In recent years, electrophysiological experiments have provided a better understanding of the functional specificity and temporal involvement of the PF networks' different components during the planning of visually guided upper limb movements. In particular, transcranial magnetic stimulation has been used to temporarily inactivate a cortical area (virtual lesions) or to assess connectivity using paired-pulse protocols)). This approach has shed new light on the neural mechanisms that underlie the planning stages of the reaching and grasping phases of transitive movements. Reaching and grasping were often presented as two distinct processes; in fact, the respective involvement of dorsolateral and dorsomedial networks may depend on the movement's complexity and the need for precise coordination between the two phases. The dorsolateral parietofrontal network (linking the anterior part of the intraparietal sulcus to the ventral premotor cortex) is involved in the grasping phase (i.e. hand shape and grip force scaling), whereas the dorsomedial part (from the posterior part of the intraparietal sulcus and the superior parieto-occipital cortex to the dorsal premotor cortex) appears to be involved not only in the reaching phase but also in more complex visually guided grasping movements. Changes in parietofrontal connectivity following brain injury might explain the impairments in visually guided upper limb movements observed in patients (such as optic ataxia and the motor component of spatial neglect). Lastly, parietofrontal changes may reflect neuronal plasticity in motor function recovery.
顶额（PF）网络将顶后皮质与运动前皮质和前额皮质连接起来，在健康人类中参与了许多运动和认知行为的控制。近年来，电生理学实验提供了更好的理解 PF 网络不同成分在视觉引导上肢运动规划中的功能特异性和时间参与。特别是，经颅磁刺激被用来暂时失活一个皮质区域（虚拟损伤）或使用成对脉冲协议评估连接性）。这种方法揭示了神经机制，这些机制为过渡运动的到达和抓握阶段的规划阶段提供了基础。到达和抓握通常被认为是两个不同的过程；事实上，背外侧和背内侧网络的各自参与可能取决于运动的复杂性和两个阶段之间精确协调的需要。背外侧顶额网络（从前内顶沟连接到腹侧运动前皮质）参与抓握阶段（即手的形状和抓握力的缩放），而背内侧部分（从前内顶沟的后部和上顶枕叶皮质到背侧运动前皮质）似乎不仅参与到达阶段，而且还参与更复杂的视觉引导抓握运动。脑损伤后顶额连接的变化可能解释了在患者中观察到的视觉引导上肢运动障碍（例如，视错觉和空间忽视的运动成分）。最后，顶额变化可能反映了运动功能恢复中的神经元可塑性。
