MRI for Neuroscience

Neurodegenerative diseases, while characterized by different pathophysiological mechanisms, share common requirements: appropriate quantitative tools to characterize non-invasively the mechanisms underlying tissue damage, and diagnostic tools for early diagnosis. In this context, the project MRI for Neuroscience aims at developing biomedical Magnetic Resonance Imaging (MRI)  technologies and analysis methods for the study of the central nervous system.

Original image by Angiolo Mosso, who at the end of the 19th century observed for the first time the increase of blood flow in activated brain areas by studying the brain surface of patients with skull fractures. Angiolo Mosso also carried out the first “non-invasive neuroimaging” study observing with a balance the redistribution of blood during brain activity (https://doi.org/10.1093/brain/awt091). This can make us smile today, but it is consistent with what we know (regional increase in blood volume up to 50% in the activated areas), and in any case the experiment was recently reproduced (https://doi.org/10.1093/brain/awt352).

In this context, the  MRI for Neuroscience aims to develop and apply biomedical Magnetic Resonance Imaging (MRI) technologies and the related analysis methods for the study of the central nervous system, with the aim of contributing to the understanding of the physiology of the human brain and the development of advanced diagnostic tools, optimized for each individual patient.

 

Real-time map of the brain response to an impulsive light stimulation at time 0. Data obtained by our group.

 

The project has a strong interdisciplinary connotation and involves researchers of various backgrounds (physicists, clinicians, engineers), that are involved in the characterization of some features of brain function through quantitative experimental approaches combined with biophysical models.

Experimental neuroscience and clinical research on neurological and psychiatric diseases are only two of the research fields where MRI is an elective tool. The key features of MRI that caused this success include the fact that it is non-invasive and can produce extremely versatile contrast on soft tissues, even without external contrast agents. The latter is related to the proper manipulation of NMR signal that can be sensitized to several biophysical and biological phenomena. In particular, MRI can be sensitized to blood oxygenation and flux, thus allowing the non-invasive study of brain function (functional MRI, fMRI).

Simulation of the water diffusion during the fMRI scan around a vessel (in the center of the figure). The diffusion of water around the vessels plays a fundamental role in fMRI, because the protons of the water molecules retain “memory” of the perturbations to the magnetic field caused by the blood having different degrees of oxygenation.

The ì project promotes MRI technological development, such as the optimization of acquisition processes, and the development of new multimodal analysis methods. We focus on multiple aspects of brain function. A point of particular importance is the full understanding of the so-called BOLD contrast, which is the basis of the fMRI techniques. We are studying the biophysical mechanisms of BOLD contrast generation, and in particular the dynamic coupling between functional activity and metabolic activity, which is the physiological substrate of brain function. Indeed, the human brain is the most energy-demanding organ, consuming approximately 20% of the total energetic budget, while weighting only around 2%.  We are also studying how fMRI can be used to characterize the dynamics of brain networks, i.e. the modulations induced by the external environment on the functional coupling between different brain areas that cooperate for the cognitive integration of sensory inputs. This objective has a strategic character, because the integration at the level of the network of the brain function has important repercussions on the understanding of the human brain highest functions, as well as of many pathologies, including neurodegenerative ones. Finally, we develop MRI techniques, for example to make fMRI imaging more suitable for studying the function of the spinal cord in multiple sclerosis, or to better characterize the mechanisms of demyelination at the brain level.

Maps of connectivity (A) and correlation (B) between the different networks related to the pupillary diameter. The dynamics of these networks allow to investigate the integration of information in the human brain (https://www.doi.org/10.3389/fnins.2019.00965).

Publications: http://marbilab.eu/publications-menu-en

Information on project H2020 691110 MICROBRADAM : http://microbradam.marbilab.eu/

International School on Magnetic Resonanace and Brain Function: http://ismrbf.marbilab.eu/

Other information on research activity and workgroup: http://www.marbilab.eu