Verteilung attentionaler Ressourcen vor Augen- und Handbewegungen
Zusammenfassung der Projektergebnisse
We move our eyes frequently – about three times per second. Even though we typically don't notice the eye movements we make, the visual system is confronted with a set of tasks around each eye movement. First, there is the problem of selecting eye movement targets which results from the fact that there are multiple objects competing to capture our eyes, and that there are task requirements to focus on particular parts of the visual world and to ignore others. Second, once selected, we need to track the relevant objects in the visual world across the multitude of eye movements. For example, we might need to keep track of a ball in a soccer match even though we move eyes around or blink. Third, on some occasions, we have to suppress unwanted saccades to objects that we don’t want to look at. In this project we investigated these three sets of problems. A first series of studies focused on the question of how we select eye movement targets. Earlier research has found that before the eyes move, participants become more sensitive to visual information presented at the location where their eye movement will go - in other words, visual attention shifts to the eye movement goal. We used this coupling between spatial attention and eye movement preparation as a basis to investigate how eye movements are planned. We observed that eye movements and shifts of spatial attention are always closely coupled, i.e., spatial attention shifts to eye movement targets regardless of whether eye movements were directed to particular locations in space (“look left”) or to particular objects (“look at green target”). Further, spatial attention was directed to eye movement locations even if participants had to look away from a salient onset object. Spatial attention could be even used to measure which locations participants are planning to look at - given a choice of two locations, spatial attention shifted to both locations which were considered to be saccadic targets. Combined, these experiments further emphasized that spatial attention and eye movement preparation are closely linked together. In a second set of studies, we investigated how we track visual information across eye movements. This is not a trivial question, as the human brain represents visual information based on where the eye is looking, and after each eye movement different objects will be at different locations relative to the direction of gaze. First, we found that humans are indeed extremely effective in tracking visual information across eye movements - we know where targets of interest are within the first 50 milliseconds after an eye movement. Our results demonstrate that this tracking is associated with visual predictions - even before the eye movement starts the visual system predicts where the object of interest will appear on the retina after the eye movement is finished. We observed such predictions as shifts of spatial attention - spatial attention shifted to locations that targets of interest will occupy after the saccade even before the eye movement started. The third set of studies investigated consequences of saccadic inhibition. We observed several surprising results. First, we found a very strong motor suppression bias - saccades where slower towards locations that had to be avoided. Second, we observed that such local saccadic inhibition abolished attentional selection at the avoided location. That is, even though it would be typically assumed that any location held in working memory should have an attentional benefit, we did not observe such a benefit. Third, we found that also working memory decreased at the locations forbidden to saccades (as compared to locations to which saccades are directed). This suggests that memory rehearsal can be done without invoking spatial attention.
Projektbezogene Publikationen (Auswahl)
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(2013). Allocation of attention across saccades. Journal of Neurophysiology, 109(5), 1425–1434
Jonikaitis, D., Szinte, M., Rolfs, M., & Cavanagh, P.
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(2013). Inhibition of saccades elicits attentional suppression. Journal of Vision, 13(6), 1–12
Dhawan, S., Deubel, H., & Jonikaitis, D.
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(2014). Target-distractor competition in the oculomotor system is spatiotopic. Journal of Neuroscience, 34(19), 6687–6691
Jonikaitis, D., & Belopolsky, A. V.
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(2016) Pre-saccadic motion integration between current and future retinotopic locations of attended objects. Journal of Neurophysiology, 116, 1592-1602
Szinte, M., Jonikaitis, D., Rolfs, M., Cavanagh, P. & Deubel, H.
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(2016). Attention allocation before antisaccades. Journal of Vision, 16(1), 11–11
Klapetek, A., Jonikaitis, D., & Deubel, H.
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(2016). Oculomotor selection underlies feature retention in visual working memory. Journal of Neurophysiology, 115(2), 1071–1076
Hanning, N. M., Jonikaitis, D., Deubel, H., & Szinte, M.
