Parallel spatial channels in the insect visual system

• Applicant: Dr. Anna Stöckl
• Subject Area: Cognitive, Systems and Behavioural Neurobiology ; Sensory and Behavioural Biology ; Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 419991121

Sensory systems – both biological and artificial ones – process highly multidimensional information. In order to extract relevant features for specific tasks, they filter the complex sensory input into parallel channels and break it down into manageable portions. The visual system acquires information about the natural world with a particularly high dimensionality. This makes it well suited to control a wide range of behaviours in humans and other animals, often as the dominant sense. But the breadth of information also increases the need for sensory filtering and for categorizing visual signals at an early stage, to process the complex input with limited neural capacities. An important example for this are parallel spatial channels in the visual system. They can help to resolve the trade-off between the spatial acuity and the contrast sensitivity in the visual system in a task-specific manner. Behavioural and physiological evidence for this strategy can be found in a number of vertebrate species. Their motion vision pathways sacrifice spatial resolution for high contrast sensitivity, while pattern detection pathways retain high spatial acuity, at the cost of contrast sensitivity. In insects, however, we do not know whether such parallel spatial filters exist. This is surprising, as insects with their tiny brains are the prime model for how limited neural capacity can control impressive behavioural complexity – a feat for which efficient peripheral filtering is crucial. In this project, I plan to close this knowledge gap by characterising parallel spatial channels in insects. Recent pilot data I obtained in the hawkmoth Macroglossum stellatarum provide the first evidence of candidate neurons that could support these parallel spatial channels. In this project, we will characterize these neurons physiologically, to understand how they contribute to spatial information processing. A thorough investigation of the spatial characteristics of different hawkmoth behaviours will reveal whether such parallel spatial channels are expressed behaviourally. Together with computational modelling, these approaches will establish whether insects use similar processing strategies as vertebrates to reduce the complexity of the visual input by filtering it into parallel spatial channels. We expect the results of this project to be paradigm shifting for the understanding of insect vision, as they might add a completely new component to the visual processing strategies described to date. These processing strategies will also provide valuable insights for the development of artificial sensory systems, for which insects provide powerful model systems. In addition, this project also lays the foundation for comparative investigations of spatial processing across animal phyla, and thereby a better understanding for the general strategies underlying neural coding of visual information.

• DFG Programme: Research Grants