Perceptual Misbinding of Color and Motion - Visual Feature Integration in Humans and Macaques
by Max Arwed Crayen
Date of Examination:2024-09-17
Date of issue:2025-02-24
Advisor:Prof. Dr. Stefan Treue
Referee:Prof. Dr. Stefan Treue
Referee:Prof. Dr. Hansjörg Scherberger
Persistent Address:
http://dx.doi.org/10.53846/goediss-11111
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Abstract
English
To interact with our environment, sensory signals must be translated into perceptions that guide our behavior. However, our noisy, crowded, and dynamic environment provides too much information to process. As a result, our brain cannot translate all sensory signals into percepts. Thus, our brain, processing the information gathered by our sensory organs, must make reasonable assumptions about the world that can then guide our perception. These assumptions do not reflect the physical reality and are modulated by different cognitive processes such as perceptual history, context, attentional deployment, or relevance. Therefore, we might misperceive certain aspects of our environment, leading to perceptual illusions or hallucinations that can misguide our behavior. Visual illusions are widespread in primates, albeit other sensory modalities are also prone to illusions. While illusions can result from visual processing in the retina or V1, others result from cortical processes that directly guide our attention, perception, and behavior. For example, the perceived coupling of visual features, like an object's color and motion direction, can be incorrect, creating perceptual illusions. Crucially, it is still unknown how the visual information processed in different areas of the visual cortex, like color and motion features, is combined into objects that make up a human’s perception. During stable visual input, physical and perceived stimulus features of illusion-inducing stimuli can either match in correctly bound percepts or differ in misbound percepts. This dichotomy might help to reveal how and where the processing of physical stimulus information stops and perception begins. To contribute to closing this knowledge gap, I investigated the misbinding of color and motion features in the peripheral visual field of humans and monkeys. The main goal of this dissertation was to examine the neural correlates of visual feature binding and misbinding in single neurons of the monkey visual cortex area MT. For this, we first investigated the characteristics of a stimulus that induces misbinding of peripheral visual features in three human psychophysics experiments. One monkey was trained on the same task design used in the third human study, but training could not be completed as experiments had to be stopped when the animal experimentation permit expired. Unfortunately, we could not observe misbound percepts in the monkey’s responses to the stimuli used in the training. Neural recordings were conducted in the motion-selective cortex area MT during the training, but we could not observe any neural correlates relating to misbound features. To improve the spatial accuracy of neural recordings and the flexibility of their positioning, we developed a new camera-based method to navigate electrodes to the target area in three dimensions. Furthermore, I contributed to a variation of this method that allows the precise positioning of microdialysis probes in the brain using custom 3D-printed recording chamber insets that guide the probe to its target location.
Keywords: Vision; Feature Binding; Neuroscience; Human Psychophysics; Eelctrophysiology; Method Development; Cognitive Neuroscience; Systems Neuroscience; Attention
