This proposal will continue neurophysiological studies on the visual processes that lead from representations of images to representations of objects. Based on the concept of the receptive field, the first stages of the visual cortex have generally been interpreted as representations of local image features, with progressive addition of details and increasing sensitivity to the context around the receptive field, but still based on local neighborhood operations. The PI's laboratory has discovered that neurons of areas V1, V2 and V4 respond differently to the same local contrast border depending on whether the border belongs to a figure on one or the other side of the border (border ownership coding), indicating an object-related feature representation and processes that require global form processing. These findings challenge the traditional concept. In order to interpret the new findings in terms of psychological and computational theories of vision, we need (1) to understand the nature of object-related feature representation at those cortical levels, and (2) to understand how object-related feature coding relates to high-level processes such as top-down attentional selection. The proposed experiments will explore object-related feature coding in V1, V2 and V4 with various paradigms of border ownership and perceptual completion and they will determine how this coding changes between the conditions of passive viewing and active visual selection in a shape discrimination task. The results will distinguish between two hypotheses: (a) that object-related signals at lower cortical levels are the byproduct of attention processes, and (b) that object-related feature representations result from independent processes which may be used by attentional mechanisms to select visual information efficiently.
| Ko, Hee-Kyoung; von der Heydt, Rüdiger (2018) Figure-ground organization in the visual cortex: does meaning matter? J Neurophysiol 119:160-176 |
| Yu, Bo; Egbejimi, Anuoluwapo; Dharmat, Rachayata et al. (2018) Phagocytosed photoreceptor outer segments activate mTORC1 in the retinal pigment epithelium. Sci Signal 11: |
| Wagatsuma, Nobuhiko; von der Heydt, Rüdiger; Niebur, Ernst (2016) Spike synchrony generated by modulatory common input through NMDA-type synapses. J Neurophysiol 116:1418-33 |
| Williford, Jonathan R; von der Heydt, Rüdiger (2016) Figure-Ground Organization in Visual Cortex for Natural Scenes. eNeuro 3: |
| von der Heydt, Rüdiger (2015) Figure-ground organization and the emergence of proto-objects in the visual cortex. Front Psychol 6:1695 |
| Martin, Anne B; von der Heydt, Rüdiger (2015) Spike synchrony reveals emergence of proto-objects in visual cortex. J Neurosci 35:6860-70 |
| O'Herron, Philip; von der Heydt, Rüdiger (2013) Remapping of border ownership in the visual cortex. J Neurosci 33:1964-74 |
| Williford, Jonathan R; von der Heydt, Rudiger (2013) Border-ownership coding. Scholarpedia J 8:30040 |
| von der Heydt, Rüdiger (2013) Neurophysiological constraints on models of illusory contours. Cogn Neurosci 4:49-50 |
| Wagemans, Johan; Elder, James H; Kubovy, Michael et al. (2012) A century of Gestalt psychology in visual perception: I. Perceptual grouping and figure-ground organization. Psychol Bull 138:1172-217 |
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