Multiscale functional imaging in the central nervous system – MULTISCALEFUNIM

This project on functional imaging in the central nervous system (CNS) touches on fundamental research, health-related issues and technological development. To understand the functioning principles of the CNS, we need experimental access to its elements, at multiple scales, a multi-scale approach is required for a comprehensive experimental investigation, covering the macro (cm) - meso (mm) - and micro (µm) -scopic levels. Large progress has been made concerning the macro (fMRI, EEG, MEG) and meso-scopic (Optical Imaging) scale in functional imaging, but the microscopic approach can still be largely optimized. In particular, 2-photon microscopic imaging is limited to a 2D scanning and no “real” 3D region of interest selections are possible, which severely limits the accessible structures and/or achievable imaging speeds and thus the scientific questions that can be addressed. Femtonics has developed proprietary technology that overcomes this problems. Yet, the technology is operative currently only in in-vitro thin brain slice preparation. Being able to bring full 3D microscopic technique to in vivo imaging, in particular in large-brain mammals such as rodents and non-human primates is a key stage along a long-term track aiming at intra-operative imaging in human subjects. Moreover, being able to image the activity of small networks in vivo in animal models of human disease will open the door to a better understanding of the pathophysiological mechanisms of debilitating neurological diseases such as epilepsy or neuro-vascular affection. Another long-term prospect is the use of such technology in awake non-human primates to unveil small network dynamics underlying cognitive functions. It shall be noticed that first two-photon imaging studies have been published in cat visual cortex only 4 years ago (Ohki et al., 2005). In this highly competitive research track, there is a risk that European brain research will be rapidly outdated. A collaborative network such as the one proposed here offers one possibility to catch-up in the race for imaging living sub-cortical and cortical tissue during functional tasks. Over the three years project, the core objective of the Hungarian-French collaboration is therefore to adapt this technology, first to whole spinal cord preparation imaging, then to in-vivo rodent and finally anesthetized non-human primate brain imaging. In France, we shall then use it to pursue our scientific questions, both at the fundamental and translational levels (see below).
On the hungarian side, the goal of consortium is to push the technological developments up to applications to human brain surgery, the long term objective being to reach the technological challenge of performing laser micro-surgery down to the single cell level, selectively. A central challenge that will be tackled is to adapt custom-developed cutting edge 2-photon microscope technology for understanding the functioning of the CNS in-vivo, and to integrate it with meso-scopic functional imaging mehods (optical imaging of intrinsic and voltage dye sygnals) already existing on-site. Therefore, using the french team’s expertise in in-vivo imaging, the hungarian partners will first realize a new microscope prototype, capable of performing in vivo imaging, starting from the current slice-preparation model. Next, the french ream will use this tool for a detailed functional exploration of the central nervous system Here a set of more physiology-oriented tasks are foreseen, to be carried out (mostly) by the French teams.