Wellcome Centre for Human Neuroimaging, University College London, UCL Queen Square Institute of Neurology, 12 Queen Square, London, WC1N 3AR, UK.
Huawei 2012 Laboratories, London, UK.
Sci Rep. 2021 Apr 2;11(1):7475. doi: 10.1038/s41598-021-87005-4.
Functional recovery after brain damage varies widely and depends on many factors, including lesion site and extent. When a neuronal system is damaged, recovery may occur by engaging residual (e.g., perilesional) components. When damage is extensive, recovery depends on the availability of other intact neural structures that can reproduce the same functional output (i.e., degeneracy). A system's response to damage may occur rapidly, require learning or both. Here, we simulate functional recovery from four different types of lesions, using a generative model of word repetition that comprised a default premorbid system and a less used alternative system. The synthetic lesions (i) completely disengaged the premorbid system, leaving the alternative system intact, (ii) partially damaged both premorbid and alternative systems, and (iii) limited the experience-dependent plasticity of both. The results, across 1000 trials, demonstrate that (i) a complete disconnection of the premorbid system naturally invoked the engagement of the other, (ii) incomplete damage to both systems had a much more devastating long-term effect on model performance and (iii) the effect of reducing learning capacity within each system. These findings contribute to formal frameworks for interpreting the effect of different types of lesions.
脑损伤后的功能恢复差异很大,取决于许多因素,包括损伤部位和范围。当一个神经元系统受损时,通过利用残留的(例如,损伤周围的)成分,可能会发生恢复。当损伤广泛时,恢复取决于是否有其他完整的神经结构可以产生相同的功能输出(即,退化)。系统对损伤的反应可能是迅速的,需要学习或两者兼而有之。在这里,我们使用包含默认发病前系统和使用较少的替代系统的单词重复生成模型,模拟了四种不同类型损伤的功能恢复。合成损伤(i)完全脱离发病前系统,保留替代系统完整,(ii)部分损伤发病前和替代系统,以及(iii)限制两者的经验依赖性可塑性。在 1000 次试验中,结果表明:(i)发病前系统的完全断开自然会引发另一个系统的介入,(ii)对两个系统的不完全损伤对模型性能有更具破坏性的长期影响,以及(iii)降低每个系统内学习能力的影响。这些发现有助于为解释不同类型损伤的影响提供形式框架。