Quantifying the structure-function of the neurovascular interface: from micro-circuits to large-scale functional organization

ended

Neuronal computations in the brain require a high metabolic budget yet the brain has extremely limited resources; calling for an on-demand, robust supply system to deliver nutrients to active regions. In most cases, neuronal activity results in an increase in blood flow to the active area, a phenomenon called functional hyperaemia. This coupling between neuronal and vascular activtuy underpins the mechanism enabling fMRI to map neuronal activity based on vascular dynamics; further, malfunction of the cellular players involved in coupling is now considered to play a key role in otherwise classically defined neurodegenerative diseases. We lack a concise description of the inner workings of this mechanism and a thorough quantitative description of the neuro-gila-vascular interface; issues that are best addressed by an investigation into the cellular mechanisms, the temporal dynamics and multi-scale spatial organization governing neurovascular coupling. My long-term goal is to provide a unified theory to encapsulate our knowledge on neurovascular coupling. Here, I hypothesize that functional hyperaemia results from the constant integration of vasoactive cues with region-dependent coupling emerging from different neuro-glia-vascular microcircuits, nuances in afferent wiring into vascular contractile elements and/or neuronal activity patterns. I will test this hypothesis with a multi-faceted correlative approach combining: two-photon awake imaging of cellular and vascular dynamics to obtain physiological data unaffected by anaesthetics; super-resolution structural imaging of intact volumes to map the fine details of micro-circuit structure; array-tomography to map in situ the neurovascular signalling machinery and novel optogenic tools to manipulate several of its specific components. I expect to offer a revolutionary mechanistic insight into one of the most basic and fundamental physiological processes behind the structure and function of the brain.