Laboratorium Voor Neuro-en Psychofysiologie, Katholieke Universiteit Leuven, Leuven, Belgium.
Department of Neurosurgery, Department of Massachusetts General Hospital, Harvard Medical School, Boston, United States.
Sci Rep. 2022 Oct 3;12(1):16527. doi: 10.1038/s41598-022-18482-4.
To perform tasks like grasping, the brain has to process visual object information so that the grip aperture can be adjusted before touching the object. Previous studies have demonstrated that the posterior subsector of the Anterior Intraparietal area is connected to area 45B, and its anterior counterpart to F5a. However, the role of area 45B and F5a in visually-guided grasping is poorly understood. Here, we investigated the role of area 45B, F5a and F5p in object processing during visually-guided grasping in two monkeys. We tested whether the presentation of an object in near peripersonal space activated F5p neurons more than objects with the same retinal size presented beyond reachable distance and conversely, whether neurons in 45B and F5a-which may encode a purely visual object representation-were less affected by viewing distance when equalizing retinal size. Contrary to our expectations, we found that most neurons in area 45B were object- and viewing distance-selective, and preferred mostly Near presentations. Area F5a showed much weaker object selectivity compared to 45B, with a similar preference for objects presented at the Near position. Finally, F5p neurons were less object selective and frequently Far-preferring. In sum, area 45B-but not F5p- prefers objects presented in peripersonal space.
为了完成抓握等任务，大脑必须处理视觉对象信息，以便在接触对象之前调整握持开口。先前的研究表明，前顶内沟的后亚区与 45B 区相连，其前亚区与 F5a 区相连。然而，45B 区和 F5a 区在视觉引导抓握中的作用还不太清楚。在这里，我们在两只猴子中研究了 45B 区、F5a 区和 F5p 区在视觉引导抓握过程中对物体处理的作用。我们测试了在近个人空间中呈现物体是否比在可触及距离之外呈现相同视网膜大小的物体更能激活 F5p 神经元，反之，当视网膜大小相等时，编码纯视觉物体表示的 45B 和 F5a 区神经元是否受观察距离的影响较小。与我们的预期相反，我们发现 45B 区的大多数神经元对物体和观察距离都有选择性，并且更喜欢近距呈现。与 45B 区相比，F5a 区的物体选择性要弱得多，对近距呈现的物体也有类似的偏好。最后，F5p 神经元的物体选择性较低，且经常更喜欢远距呈现。总之，45B 区（而不是 F5p 区）更喜欢近个人空间中呈现的物体。
