Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium.
Leuven Brain Institute, Leuven, Belgium.
Cereb Cortex. 2019 Jun 1;29(6):2588-2606. doi: 10.1093/cercor/bhy128.
The brain has a remarkable capacity to recover after lesions. However, little is known about compensatory neural adaptations at the systems level. We addressed this question by investigating behavioral and (correlated) functional changes throughout the cortex that are induced by focal, reversible inactivations. Specifically, monkeys performed a demanding covert spatial attention task while the lateral intraparietal area (LIP) was inactivated with muscimol and whole-brain fMRI activity was recorded. The inactivation caused LIP-specific decreases in task-related fMRI activity. In addition, these local effects triggered large-scale network changes. Unlike most studies in which animals were mainly passive relative to the stimuli, we observed heterogeneous effects with more profound muscimol-induced increases of task-related fMRI activity in areas connected to LIP, especially FEF. Furthermore, in areas such as FEF and V4, muscimol-induced changes in fMRI activity correlated with changes in behavioral performance. Notably, the activity changes in remote areas did not correlate with the decreased activity at the site of the inactivation, suggesting that such changes arise via neuronal mechanisms lying in the intact portion of the functional task network, with FEF a likely key player. The excitation-inhibition dynamics unmasking existing excitatory connections across the functional network might initiate these rapid adaptive changes.
大脑在受损后具有很强的恢复能力。然而，对于系统水平上的代偿性神经适应，我们知之甚少。我们通过研究局部、可逆失活诱导的整个皮层的行为和（相关的）功能变化来解决这个问题。具体来说，猴子在进行一项要求很高的隐蔽空间注意任务时，外侧顶内沟（LIP）被 muscimol 失活，同时记录全脑 fMRI 活动。失活导致与任务相关的 fMRI 活动在 LIP 特异性减少。此外，这些局部效应引发了大规模的网络变化。与大多数动物相对于刺激主要处于被动状态的研究不同，我们观察到异质效应，与 LIP 连接的区域（尤其是 FEF）的任务相关 fMRI 活动的 muscimol 诱导增加更为明显。此外，在 FEF 和 V4 等区域，fMRI 活动的 muscimol 诱导变化与行为表现的变化相关。值得注意的是，远程区域的活动变化与失活部位的活性降低无关，这表明这些变化是通过功能任务网络中完整部分的神经元机制引起的，FEF 可能是关键参与者。揭示整个功能网络中现有兴奋性连接的兴奋-抑制动力学可能会引发这些快速适应变化。
