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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. Michael Niedeggen Research associate Lars Michael Project description Our previous experiments have demonstrated that the conscious representation of visual features (motion coherence, orientation switch) which are relevant to the subject critically depend on the previous presentation of distractors. Distractors share the characteristics of the relevant target event, and activate gradually an inhibition mechanism. Using event-related brain potentials (ERPs), a direct neural correlate of this cumulative inhibition effect was identified. We assume that the paradigm of distractor-induced blindness allows us to examine a central gating process which permits - or prevents – visual stimuli to enter conscious awareness. In our current research project we will focus on the following questions: (1) Can we separate different mechanisms contributing to the generation of the inhibition effect, and its release? For this reason, the temporal dynamics of the distractor effect will be examined more closely. (2) Does the sensitivity to distractors account for interindividual differences? For this reason, the cumulative distractor effect will be examined in ‘responders’ and ‘non-responders’. (3) Does the distractor effect interact with the pre-target EEG activity? Target detection also depends on the state of the cortical system, as measured by EEG rhythm and / or EEG coherence. We like to examine, whether distractor presentation also affects these brain rhythms. (4) Can we identify the distractor effect in other paradigms interfering with the processing of visual stimuli? We will try to induce a cumulative distracter effect in two related paradigms, attentional blink and negative priming. (5) Can we validate a computational model on the distractor-induced blindness effect? Assuming that the basal ganglia contribute to the generation of the effect, we will focus on the observer’s motor response system.
Selected papers
Niedeggen M., Sahraie A., Hesselmann G., Milders M. & Blakemore C. (2002). Is experimental motion blindness due to sensory suppression? An ERP approach. Cognitive Brain Research, 13, 241-247.
Niedeggen, M., Hesselmann, G., Sahraie, A., Milders, M. & Blakemore, C. (2004): Probing the prerequites for motion blindness. Journal of Cognitive Neuroscience, 16, 584-597. |
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Functional properties of distractor-induced blindness |
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funded by the German Research Foundation (DFG) |
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