Functional MRI of Synaptic Plasticity

Since its discovery in the early 1990s, blood oxygen level dependent signal-based functional magnetic resonance imaging (fMRI) has become a fundamental technique for the study of brain activity in basic and clinical research. Functional MRI provides an indirect but robust and quantitative readout of brain activity through the tight coupling between cerebral blood flow and neuronal activation, the so-called neurovascular coupling. Combined with experimental techniques such as electrophysiology, intracerebral microstimulation, optogenetics, or pharmacogenetics, it provides a powerful framework to investigate the impact of specific circuit manipulations on overall brain dynamics. In this chapter we review the contribution of some of these techniques to the understanding of short- and long-term plasticity processes and provide a comprehensive account of the protocols used in our laboratory. Considerations on the interpretation of the results and the limitations of the approach are also discussed.