Dr. Diba published a new article in Neuron: Taxidis J, Anastassiou CA, Diba K, Koch C (2015) Local Field Potentials Encode Place Cell Ensemble Activation during Hippocampal Sharp Wave Ripples. Neuron 87(3):590-604. PMID: 26247865 http://www.sciencedirect.com/science/article/pii/S0896627315006364
Whether and how the activation of spiking cell ensembles can be encoded in the local field potential (LFP) recorded with extracellular electrodes remains unanswered. In a collaboration between Kamran Diba’s Neural Circuits and Memory Lab at the UW-Milwaukee, and Christof Koch’s Neuronal Computation Group at the California Institute of Technology (Caltech), the authors combined realistic biophysical modeling with in vivo electrophysiological recordings in the rat hippocampus to demonstrate how spatiotemporal features of the LFP encode the activation of place cell ensembles during hippocampal sharp wave ripples.
They show that multi-site perisomatic LFP amplitudes, in the 150–200 Hz frequency band, reliably reflect spatial constellations of spiking cells, embedded within non-spiking populations, and encode activation of local place cell ensembles during in vivo replays. Spatiotemporal patterns in the LFP remained consistent between sequence replays, in conjunction with the ordered activation of place cell ensembles.
Clustering such patterns provides an efficient segregation of replay events from nonreplay- associated ripples. This work demonstrates how spatiotemporal ensemble spiking is encoded extracellularly, providing a window for efficient, LFP-based detection and monitoring of structured population activity in vivo.