Wellcome Centre for Integrative Neuroimaging, Oxford Centre for Functional MRI of the Brain, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom.
Lyon Neuroscience Research Center, ImpAct (Integrative, Multisensory, Perception, Action & Cognition) team INSERM U1028, CNRS UMR5292, University Lyon 1, Bron, France.
Elife. 2017 Sep 12;6:e26602. doi: 10.7554/eLife.26602.
Right brain injury causes visual neglect - lost awareness of left space. During prism adaptation therapy, patients adapt to a rightward optical shift by recalibrating right arm movements leftward. This can improve left neglect, but the benefit of a single session is transient (~1 day). Here we show that tonic disinhibition of left motor cortex during prism adaptation enhances consolidation, stabilizing both sensorimotor and cognitive prism after-effects. In three longitudinal patient case series, just 20 min of combined stimulation/adaptation caused persistent cognitive after-effects (neglect improvement) that lasted throughout follow-up (18-46 days). Moreover, adaptation without stimulation was ineffective. Thus stimulation reversed treatment resistance in chronic visual neglect. These findings challenge consensus that because the left hemisphere in neglect is pathologically over-excited it ought to be suppressed. Excitation of left sensorimotor circuits, during an adaptive cognitive state, can unmask latent plastic potential that durably improves resistant visual attention deficits after brain injury.
右脑损伤会导致视觉忽视——即对左侧空间的无意识。在棱镜适应疗法中，患者通过将右臂运动向左重新校准来适应向右的光偏移。这可以改善左侧忽视，但单次治疗的效果是短暂的（约 1 天）。在这里，我们表明，在棱镜适应过程中左运动皮层的紧张性抑制增强了巩固作用，稳定了感觉运动和认知棱镜后效。在三个纵向患者病例系列中，仅 20 分钟的联合刺激/适应就导致了持久的认知后效（忽视改善），并在整个随访期间（18-46 天）持续存在。此外，没有刺激的适应是无效的。因此，刺激逆转了慢性视觉忽视的治疗抵抗。这些发现挑战了共识，即由于忽视中的左半球病理性过度兴奋，它应该被抑制。在适应性认知状态下，对左感觉运动回路的兴奋可以揭示潜在的可塑性潜力，从而持久改善脑损伤后的顽固视觉注意力缺陷。
