Formative research on a post-discharge monitoring program using SQ-LNS to reduce acute malnutrition relapse risk in Mali : a qualitative study.

Brain function emerges from the coordinated interactions of global brain areas and local neural circuits. Investigation of brain function therefore benefits from experimental methods that can probe neural activity throughout the whole brain, preferably with a high spatial and temporal resolution at the level of local neuronal circuits. Widely adopted imaging methods, such as functional magnetic resonance imaging (fMRI), allow non-invasive, whole-brain recordings but compromise spatiotemporal resolution and source specificity for coverage and non-invasiveness. In particular, blood-oxygen-level-dependent (BOLD) fMRI measures neural activity indirectly through changes in blood oxygenation and volume driven by neurovascular coupling, a process with an inherent temporal delay. The BOLD fMRI signal is therefore considered a slow, mean proxy of local brain activity, with a limited ability to resolve local neural-circuit dynamics. By contrast, opto-physiological recording methods, such as in vivo single- and multi-photon imaging, can capture the membrane voltages and Ca levels of genetically defined neural circuits at cellular resolution. Recent Ca imaging studies in rodents have demonstrated the possibility of simultaneously monitoring thousands of individual cells at kHz sampling rates. However, optical methods typically require invasive surgery to gain access to the brain and can simultaneously measure only up to a few cortical brain regions of interest.