In vivo two-photon-microscope with unit for holographic optogenetic stimulation

• Subject Area: Neurosciences
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 571197315

The proposed two-photon microscope has an extended field of view compared to the standard and features a resonance scanner and an electrically adjustable lens for fast volumetric imaging as well as a holographic illumination module for optogenetics. It will be used for in vivo imaging and optogenetic manipulation of neuronal activity in mice, in Drosophila and in human 3D cell cultures. The proposed two-photon microscope is a central part of my laboratory equipment in the context of my appointment at the RPTU Kaiserslautern. My research group is involved in basic research on signal processing in the visual and auditory cortex and translational research on the neurobiological causes of psychiatric disorders. Our fundamental question is how brain function and dysfunction derive from synaptic and cellular physiology and neuronal circuit organization. Our research approach is a cross-scale analysis of the different levels of neuronal organization from molecules via synapses, neurons, the neuronal circuit up to brain function. Our central method in the mouse model is to first record the activity of neurons in vivo during behavior or sensory stimulation and then to investigate synaptic and cellular physiology as well as neuronal circuit organization in the same neurons in brain slices. For the measurement of neuronal activity in vivo, fast imaging with a large field of view across multiple focal planes is of great importance to simultaneously include a large number of neurons in the cortex whose population dynamics correlate with the animal's behavior and to identify neurons with activity abnormalities. In order to test and validate our results from the correlative measurements for causality in the future, the holographic illumination module is required, which allows targeted optogenetic manipulation of defined groups of neurons to test the causality between activity patterns and behavior. In addition to mouse models, human neuron cultures based on induced pluripotent stem cells from psychiatric patients and healthy volunteers are used. Similar to the mouse model, rapid volumetric imaging is required to detect activity abnormalities in human 3D neuron cultures and subsequently to investigate the causes at the synaptic, cellular and neuronal circuit level and ultimately correlate these with the symptoms and the genetic and clinical diagnosis of the patients. At the site, there is no microscope available for carrying out these research projects. The proposed two-photon microscope, including the holographic illumination module, will enable us to continue our research in my working group at the RPTU Kaiserslautern and to pursue new research questions in the future.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: In vivo Zwei-Photonen-Mikroskop mit Modul für holographische optogenetische Stimulation
• Instrumentation Group: 5090 Spezialmikroskope
• Applicant Institution: Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
• Leader: Professor Dr. Volker Scheuss