Visual functions of the primate superior colliculus

• Applicant: Professor Dr. Ziad Hafed, Ph.D., since 1/2021
• Subject Area: Cognitive, Systems and Behavioural Neurobiology
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 436339786

Foveal vision affords us the ability to recognize complex objects, but successfully orienting the fovea to the object of interest in the first place is equally important. Investigations of object recognition have overwhelmingly focused on foveal vision, thereby, ignoring the mechanisms behind peripheral object detection that facilitate foveal orienting. We will fill this important gap through novel investigation of an evolutionarily conserved brain structure, the midbrain superior colliculus (SC), which can contribute simultaneously to both peripheral object detection and orienting of the fovea for detailed object processing. In primates, despite diverse inputs from both retina and visual cortex, our understanding of the SC’s visual functions remains to be poor. We hypothesize that the SC facilitates peripheral object detection through visual selection mechanisms, thereby, bridging the dichotomy between visual object recognition at the fovea, on the one hand, and visual orienting towards peripheral objects, on the other. We will exhaustively characterize SC visual functions in the context of visual object processing and highlight the underestimated role that this structure can play in object detection. We will specifically investigate three different aspects of SC visual processing, which we deem critical for object vision: global form-based object detection, motion-based object segmentation, and finally, low spatial frequency sensitivity for visual forms. Most importantly, we will also test the extent to which SC visual object processing is independent of inputs from primary visual cortex, the main gateway to subsequent object processing in cortical ventral stream areas. We will use neuronal population recording and manipulation techniques in non-human primates (rhesus macaques), and we will compare SC visual properties with and without reversible inactivation of primary visual cortex. Our experiments will demonstrate neuronal computations for vision that are performed outside of visual cortex, thereby, having a major impact on our understanding of visual processing pathways in primates.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Dr. Amarender Bogadhi, Ph.D., until 12/2020