Deep 3-photon brain maging with wide scatter compensation

To understand the functioning of a brain, it would be ideal to be able to observe it while it is thinking. It is now possible to see the activity of individual brain cells (neurons) directly under the microscope using special stains. However, the "penetration depth" of today`s microscopes is too shallow to reach brain areas beyond a few tenths of a millimeter deep. The brain tissue itself scatters the scanning laser beam and the image quality deteriorates with increasing scan depth. Our research project aims to develop methods to compensate for scattered light. These should allow lasers to be focused far into tissue, thus enabling the acquisition of high-resolution images in deeper tissue layers (beyond 1 mm depth). We combine this "adaptive optics" technique with laser light in the near-infrared range (1.3m wavelength) to further reduce scattering effects. Our project involves three main objectives: First, we will significantly accelerate stray light compensation techniques to keep up with the speed of internal micro-movements of living tissue. Second, we will significantly expand the corrected image areas. Third, we will increase the imaging depth to cover significant portions of the mouse brain. This is a key requirement to obtain a comprehensive picture of its functioning.