Contextual influences on object recognition investigated by means of steady-state visual evoked potentials

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The present research proposal aims at investigating how context information influences object recognition. Contextual information can be provided by means of a scenic background or by semantic associations between several objects. Both scenarios are characterized by the perception of the so-called "gist" of the visual input, i.e. the perception of the general meaning of a scene. Up-today, the neuronal mechanisms underlying these contextual influences on object recognition are not well understood. One reason for this shortcoming lies in the methodological problem to separate the brain response elicited by a context from the cortical activation related to a target object. More precisely, conventional neuroscientific methods (e.g. BOLD signals) solely mirror the intermingled signal to all constituting elements of a multi-stimulus display. We intend to overcome this limitation by making use of the steady-state visual evoked potential (SSVEP), a specific technique in electroencephalogram (EEG) research. Besides other advantages, the SSVEP method can disentangle neuronal responses elicited by simultaneously presented stimuli by means of tagging each stimulus with an individual driving frequency (for example by presenting a familiar object at 12 Hz and a related scenic background at 9 Hz). Next, the EEG signal is transformed to its spectral components (in the above example the 12 Hz object response and the 9 Hz background response). We suggest conducting six experiments thereby taking advantage of the SSVEP methods major strengths. These experiments aim at answering the following two main research questions: (1) What are the neuronal underpinnings of objects recognition in context? (2) Which basic cognitive functions underlie contextual influences on object recognition (e.g. specific memory processes)? To sum, the proposed research project will provide systematic information about neuronal and cognitive mechanisms of object recognition under natural viewing conditions (i.e. with contextual information). The suggested experiments will thereby complement and extend current knowledge derived from studying object recognition in isolation (i.e. without context).