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Neuro-cognitive mechanisms of conscious and unconscious visual perception |
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Research Network |
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Principal investigator Prof. Dr. Rolf Verleger Research associate Dr. Kamila Śmigasiewcz Project description The mechanisms that underlie the great perceptual advantage of the right hemisphere in 2-channel-RSVP tasks (rapid serial visual presentation) will be studied by neurophysiology and by experimental psychology. The results will be used to substantiate a hypothesis about the relevance of right-hemisphere dominance for constructing conscious percepts. In this task, two simultaneous series of letters are displayed rapidly (10/s), left and right from fixation. Two targets have to be identified, “T1” and “T2“. When T1 and T2 are on different sides, T2 is identified much better with right T1 & left T2 than with left T1 & right T2. Dominance of the right hemisphere, suggested by these results, is also evident by earlier peak latencies and longer sustained duration of EEG-potentials above the right than the left visual cortex. By varying features of the task and the display, that special feature of the paradigm is to be identified that leads to that observed asymmetry of perceptual performance. Neurophysiologically, the EEG indicators of right-hemisphere activation, as obtained so far, will be tested for their specificity as correlates of the behavioral effects. The locus of their generation will be searched by means of higher topographical resolution and by fMRT (functional magnetic resonance tomography), and the right hemisphere will be tested for its functional relevance by interfering with its activity by means of TMS (transcranial magnetic stimulation). Selected papers Verleger, R., Möller, F., Kuniecki, M., Śmigasiewicz, K., Groppa, S., & Siebner, H.R. (in press) The left visual-field advantage in rapid visual presentation is further amplified rather than reduced by posterior-parietal rTMS. Experimental Brain Research. Verleger, R. Markers of awareness? EEG potentials evoked by faint and masked events, with special reference to the "attentional blink (2010) In I. Czigler & I. Winkler (Eds.): Unconscious memory representations in perception: Processes and mechanisms in the brain (p. 37-70). John Benjamins Publishing Company. Verleger, R., Sprenger, A., Gebauer, S., Fritzmannova, M., Friedrich, M., Kraft, S., & Jaśkowski, P. (2009) On why left events are the right ones: Neural mechanisms underlying the left-hemifield advantage in rapid serial visual presentation. Journal of Cognitive Neuroscience 21:474-488 Verleger, R., & Jaśkowski, P. (2007) Disentangling neural processing of masked and masking stimulus by means of event-related contralateral – ipsilateral differences of EEG potentials. Advances in Cognitive Psychology 3:193-210 Jaśkowski, P., Białuńska, A., Tomanek, M., & Verleger, R. (2008) Mask- and distractor-triggered inhibitory processes in the priming of motor responses: An EEG study. Psychophysiology, 45:70-85 Śmigasiewicz, K., Shalgi, S., Hsieh, S., Möller, F., Jaffe, S., Chang, C.C., & Verleger, R. (in press) Left visual-field advantage in the dual-stream RSVP task and reading direction: A study in three nations. Neuropsychologia
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On the role of right-hemisphere dominance for constructing conscious percepts |
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funded by the German Research Foundation (DFG) |
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