Neuronal activity can be quantified by measuring the firing of single neurons or summated population events. Local field potentials (LFPs) reflect the latter. Recording of LFPs from multiple nearby cortical sites yields patterns of activity that change dynamically across time. We quantified the number or “repertoire” of these patterns in visual cortex as an index of information capacity in different states of consciousness. Surprisingly, the repertoire was not reduced during anesthesia. What does this mean? It could be that visual cortex is not representative of the hypothesized shrinkage of information capacity or that the mesoscopic level of measurement is too coarse to detect it. Obviously, spikes convey more specific information than LFPs. Regardless, these measurements will have to be repeated in many other brain areas.
Hudetz AG, Vizuete JA, Pillay S, Mashour GA. Repertoire of mesoscopic cortical activity is not reduced during anesthesia. Neuroscience. 2016 Dec 17;339:402-417. PubMed PMID: 27751957; PubMed Central PMCID: PMC5118138.*
*This work received Best Abstract presentation at the 2016 Annual Meeting of the American Society of Anesthesiologists.