Multimodal integration on subcellular level in single neurons

• Applicant: Dr. Stefan Weigel
• Subject Area: Molecular Biology and Physiology of Neurons and Glial Cells
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269673298

Multimodal integration of different sensory information is essential for survival as it improves speed and reliability of target selection and the appropriate responses. In birds, the optic tectum (superior colliculus in mammals) is the most important integrative brain area. Here, all spatial sensory information is organized in a multimodal space map, and many neurons in the optic tectum respond to several modalities. However, little is known about how multimodal integration is achieved on the cellular and subcellular level.The proposed project will investigate multimodal integration on the subcellular level by hybrid voltage sensor imaging (hVoS) in acute brain slices of the chicken. This technique (where a fluorophore is quenched by the molecule dipicrylamine depending on the membrane voltage) allows for a submillisecond recording of neuronal activity with a high spatial acuity. We will study multimodal integration in tectal Shepherd´s crook neurons. Several lines of evidence point towards a crucial role of these neurons in multimodal processes, and their characteristic morphology suggests a specialization for both spatial and temporal integration of different sensory channels. We will focus on how information arriving at the different input zones are processed in the Shepherd´s crook neurons. To this aim, we will stimulate presynaptically at both the visual and the auditory afferents. Three major issues will be investigated: 1) axopetal information flow for each sensory modality separately, 2) the importance of synchrony in multimodal integration (coincidence detection) and 3) gating of visual input at apical dendrites by the somatic potential. The data gathered here will be validated in a conductance-based simulation of the Shepherd´s crook neuron.The proposed project will further our understanding of dendritic computation and signal integration and foster our knowledge on multimodal integration in general.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Harald Luksch