Department of Psychology, University of Cambridge, Cambridge, United Kingdom.
Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.
Elife. 2020 Nov 10;9:e57637. doi: 10.7554/eLife.57637.
Adapting to the environment statistics by reducing brain responses to repetitive sensory information is key for efficient information processing. Yet, the fine-scale computations that support this adaptive processing in the human brain remain largely unknown. Here, we capitalise on the sub-millimetre resolution of ultra-high field imaging to examine functional magnetic resonance imaging signals across cortical depth and discern competing hypotheses about the brain mechanisms (feedforward vs. feedback) that mediate adaptive processing. We demonstrate layer-specific suppressive processing within visual cortex, as indicated by stronger BOLD decrease in superficial and middle than deeper layers for gratings that were repeatedly presented at the same orientation. Further, we show altered functional connectivity for adaptation: enhanced feedforward connectivity from V1 to higher visual areas, short-range feedback connectivity between V1 and V2, and long-range feedback occipito-parietal connectivity. Our findings provide evidence for a circuit of local recurrent and feedback interactions that mediate rapid brain plasticity for adaptive information processing.
通过减少大脑对重复感觉信息的反应来适应环境统计是有效信息处理的关键。然而，支持人类大脑这种自适应处理的精细计算在很大程度上仍是未知的。在这里，我们利用超高场成像的亚毫米分辨率来检查皮质深度的功能磁共振成像信号，并辨别关于介导自适应处理的大脑机制（前馈与反馈）的竞争假说。我们证明了视觉皮层中的层特异性抑制处理，表现为在相同方向重复呈现的光栅在浅层和中层的 BOLD 减少比深层更强。此外，我们还展示了适应的改变功能连接：从 V1 到更高视觉区域的前馈连接增强，V1 和 V2 之间的短程反馈连接，以及枕顶间的长程反馈连接。我们的研究结果为局部递归和反馈相互作用的回路提供了证据，该回路介导了快速的大脑可塑性以进行自适应信息处理。
