Radboud University, Donders Institute for Brain, Cognition and Behaviour, 6525 EN, Nijmegen, The Netherlands.
The Wellcome Trust Centre for Neuroimaging, UCL, 12 Queen Square, London, UK.
Sci Rep. 2017 Jul 18;7(1):5677. doi: 10.1038/s41598-017-05888-8.
Research suggests that perception and imagination engage neuronal representations in the same visual areas. However, the underlying mechanisms that differentiate sensory perception from imagination remain unclear. Here, we examine the directed coupling (effective connectivity) between fronto-parietal and visual areas during perception and imagery. We found an increase in bottom-up coupling during perception relative to baseline and an increase in top-down coupling during both perception and imagery, with a much stronger increase during imagery. Modulation of the coupling from frontal to early visual areas was common to both perception and imagery. Furthermore, we show that the experienced vividness during imagery was selectively associated with increases in top-down connectivity to early visual cortex. These results highlight the importance of top-down processing in internally as well as externally driven visual experience.
研究表明，感知和想象在相同的视觉区域中利用神经元的表象。然而，区分感觉感知和想象的潜在机制仍不清楚。在这里，我们研究了在感知和想象期间额顶叶和视觉区域之间的定向耦合（有效连通性）。我们发现，与基线相比，在感知过程中，自上而下的耦合增加，而在感知和想象过程中，自下而上的耦合增加，在想象过程中增加更多。从额叶到早期视觉区域的耦合调制对感知和想象都是共同的。此外，我们还表明，在想象过程中体验到的生动感与早期视觉皮层的自上而下连接的增加有选择性地相关。这些结果强调了在内部和外部驱动的视觉体验中，自上而下的处理的重要性。
