critical role of active membrane currents. Neuron 79:375–390 Riera JJ, Ogawa T, Goto T, Sumiyoshi A, Nonaka H, Evans A, Miyakawa H, Kawashima R (2012) Pitfalls in the dipolar model for the neocortical EEG sources. J Neurophysiol 108:956–975 Telenczuk B, Baker SN, Herz AVM, Curio G (2011) High-frequency EEG covaries with spike burst pat- terns detected in cortical neurons. J Neurophysiol 105:2951–2959 Whittingstall K, Logothetis NK (2009) Frequency-band coupling in surface EEG reflects spiking activity in monkey visual cortex. Neuron 64:281–289 Zanos TP, Mineault PJ, Pack CC (2011) Removal of spurious correlations between spikes and local field potentials. J Neurophysiol 105:474–486 Local Field Potential, Spike Contribution ▶ Local Field Potential, Relationship to Unit Activity Local Field Potential, Spike-Triggered Average ▶ Local Field Potential, Relationship to Unit Activity Local Field Potential, Synchrony of Ariana Frederick 1 , Jonathan Bourget-Murray 1,2 and Richard Courtemanche 1 1 FRQS Groupe de Recherche en Neurobiologie Comportementale/Center for Studies in Behavioral Neurobiology (CSBN), Department of Exercise Science, Concordia University, Montre ´al, QC, Canada 2 C.M. Program, Faculty of Medicine, McGill University, Montre ´al, QC, Canada Synonyms Coherence of local field potentials; Coupling of local field potentials; Cross-correlation of local field potentials Definition Synchrony of local field potentials (LFP) is a neurophysiological property that represents the correlation of activity between simulta- neously recorded networks. Its measurement indicates how tightly multiple local networks are coupled. LFP synchrony indicates a potential interaction between the recorded sites and a possible mechanism to facilitate syn- aptic transmission and network-to-network communication. Detailed Description The Neural Basis of Local Field Potentials Local field potentials (LFPs) are the integrated electrical signals recorded from a local popula- tion of neurons. Each neuron’s intracellular membrane potential provides an indication of its excitability, its readiness to fire. Using low-impedance electrodes, small intracellular synaptic voltage fluctuations from a population of cells combine together into a spatiotemporally integrated signal. Much like electroencephalog- raphy (EEG), the LFP represents the compound activity from multiple postsynaptic potentials and provides an integrated electrical signal recorded from the local population of neurons. When recording the LFP activity from multiple regions simultaneously, neurophysiologists can compare the changing patterns of activity in time, studying both the presence and characteristics of oscilla- tions within each area and the changes in syn- chrony between areas. Local Field Potential Oscillations Activity of neurons around an electrode can tem- porally coordinate into a series of alternating membrane potentials, giving rise to LFP oscilla- tions. These oscillations can be classified into distinctive frequency bands, corresponding to different cycle times. Oscillatory activity can be mediated by local circuit properties, either par- tially or totally, but can also be influenced by large-scale network inputs. Neuronal firing pat- terns can become phase-locked to the collective L 1584 Local Field Potential, Spike Contribution