In spite of their apparent stochasticity, neuronal circuits display a highly structured spontaneous activity even in the absence of sensory stimulation. Large-scale recordings have shown that neuronal network dynamics is characterized by the coordinated activity of so-called cell assemblies, which can be identified using dimensionality reduction techniques. This complex activity is well modelled by attractor states associated to specific behavioral patterns. Understanding the computational origin of these states and the mechanisms underlying spontaneous transitions between them is a longstanding major issue in systems neuroscience. As part of my M2 internship project, I developed an experimental approach in order to study evoked neuronal activity in the vertebrate brain.