Modern recording techniques such as multi-electrode arrays and two-photon imaging methods are capable of simultaneously monitoring the activity of large neuronal ensembles at single cell resolution. These methods finally give us the means to address some of the most crucial questions in systems neuroscience: what are the dynamics of neural population activity? How do populations of neurons perform computations? What is the functional organization of neural ensembles?
Macke, J., Berens, P., & Bethge, M. (2011). Statistical Analysis of Multi-Cell Recordings: Linking Population Coding Models to Experimental Data. Frontiers in Computational Neuroscience, 5. https://doi.org/10.3389/fncom.2011.00035