Decoding sensation and perception over time with EEG pattern cross-classification H Hogendoorn1, F A Verstraten2 |
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1Department of Experimental Psychology, Universiteit Utrecht, Netherlands |
| Visual representations evolve as visual information passes through successive processing stages on the way from the retina to conscious awareness. Using EEG in combination with a visual illusion that allowed us to dissociate veridical and perceived position, we tracked the neural representation of visual position over time. Multivariate pattern classification of single EEG trials showed that the veridical position of a visual stimulus can be decoded from EEG activity very rapidly following stimulus presentation, as would be expected from the known retinotopic organization of early visual areas. However, we show that the illusory, rather than veridical location can also be decoded very rapidly: already around 80 ms after stimulus onset, the classifier is better able to distinguish two stimuli when they are perceived to be far apart than when they are perceived to be close together – even when both stimulus pairs are in identical positions. Finally, we show that the information coding veridical and perceived position has dissociable neural origins. Using this technique we are able to trace the evolution of neural representations from low-level sensation to higher-order perception over both space and time. |
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