Pre-stimulus alpha activity modulates long-lasting unconscious feature integration
Pre-stimulus alpha (α) activity can influence perception of shortly presented, low-contrast stimuli. The underlying mechanisms are often thought to affect perception exactly at the time of presentation. In addition, it is suggested that α cycles determine temporal windows of integration. However, in...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2023-09-01
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| Series: | NeuroImage |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1053811923004494 |
| _version_ | 1797744305680416768 |
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| author | Maëlan Q. Menétrey Michael H. Herzog David Pascucci |
| author_facet | Maëlan Q. Menétrey Michael H. Herzog David Pascucci |
| author_sort | Maëlan Q. Menétrey |
| collection | DOAJ |
| description | Pre-stimulus alpha (α) activity can influence perception of shortly presented, low-contrast stimuli. The underlying mechanisms are often thought to affect perception exactly at the time of presentation. In addition, it is suggested that α cycles determine temporal windows of integration. However, in everyday situations, stimuli are usually presented for periods longer than ∼100 ms and perception is often an integration of information across space and time. Moving objects are just one example. Hence, the question is whether α activity plays a role also in temporal integration, especially when stimuli are integrated over several α cycles. Using electroencephalography (EEG), we investigated the relationship between pre-stimulus brain activity and long-lasting integration in the sequential metacontrast paradigm (SQM), where two opposite vernier offsets, embedded in a stream of lines, are unconsciously integrated into a single percept. We show that increases in α power, even 300 ms before the stimulus, affected the probability of reporting the first offset, shown at the very beginning of the SQM. This effect was mediated by the systematic slowing of the α rhythm that followed the peak in α power. No phase effects were found. Together, our results demonstrate a cascade of neural changes, following spontaneous bursts of α activity and extending beyond a single moment, which influences the sensory representation of visual features for hundreds of milliseconds. Crucially, as feature integration in the SQM occurs before a conscious percept is elicited, this also provides evidence that α activity is linked to mechanisms regulating unconscious processing. |
| first_indexed | 2024-03-12T15:07:51Z |
| format | Article |
| id | doaj.art-02f33099a003441c91a2729e586e6c2e |
| institution | Directory Open Access Journal |
| issn | 1095-9572 |
| language | English |
| last_indexed | 2024-03-12T15:07:51Z |
| publishDate | 2023-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | NeuroImage |
| spelling | doaj.art-02f33099a003441c91a2729e586e6c2e2023-08-12T04:33:51ZengElsevierNeuroImage1095-95722023-09-01278120298Pre-stimulus alpha activity modulates long-lasting unconscious feature integrationMaëlan Q. Menétrey0Michael H. Herzog1David Pascucci2Corresponding author.; Laboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, SwitzerlandLaboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, SwitzerlandLaboratory of Psychophysics, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, SwitzerlandPre-stimulus alpha (α) activity can influence perception of shortly presented, low-contrast stimuli. The underlying mechanisms are often thought to affect perception exactly at the time of presentation. In addition, it is suggested that α cycles determine temporal windows of integration. However, in everyday situations, stimuli are usually presented for periods longer than ∼100 ms and perception is often an integration of information across space and time. Moving objects are just one example. Hence, the question is whether α activity plays a role also in temporal integration, especially when stimuli are integrated over several α cycles. Using electroencephalography (EEG), we investigated the relationship between pre-stimulus brain activity and long-lasting integration in the sequential metacontrast paradigm (SQM), where two opposite vernier offsets, embedded in a stream of lines, are unconsciously integrated into a single percept. We show that increases in α power, even 300 ms before the stimulus, affected the probability of reporting the first offset, shown at the very beginning of the SQM. This effect was mediated by the systematic slowing of the α rhythm that followed the peak in α power. No phase effects were found. Together, our results demonstrate a cascade of neural changes, following spontaneous bursts of α activity and extending beyond a single moment, which influences the sensory representation of visual features for hundreds of milliseconds. Crucially, as feature integration in the SQM occurs before a conscious percept is elicited, this also provides evidence that α activity is linked to mechanisms regulating unconscious processing.http://www.sciencedirect.com/science/article/pii/S1053811923004494Alpha oscillationsPre-stimulus effectsLong-lasting feature integrationUnconscious processing |
| spellingShingle | Maëlan Q. Menétrey Michael H. Herzog David Pascucci Pre-stimulus alpha activity modulates long-lasting unconscious feature integration NeuroImage Alpha oscillations Pre-stimulus effects Long-lasting feature integration Unconscious processing |
| title | Pre-stimulus alpha activity modulates long-lasting unconscious feature integration |
| title_full | Pre-stimulus alpha activity modulates long-lasting unconscious feature integration |
| title_fullStr | Pre-stimulus alpha activity modulates long-lasting unconscious feature integration |
| title_full_unstemmed | Pre-stimulus alpha activity modulates long-lasting unconscious feature integration |
| title_short | Pre-stimulus alpha activity modulates long-lasting unconscious feature integration |
| title_sort | pre stimulus alpha activity modulates long lasting unconscious feature integration |
| topic | Alpha oscillations Pre-stimulus effects Long-lasting feature integration Unconscious processing |
| url | http://www.sciencedirect.com/science/article/pii/S1053811923004494 |
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