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. Author manuscript; available in PMC: 2011 Jul 11.
Published in final edited form as: Neuron. 2009 Apr 30;62(2):171–189. doi: 10.1016/j.neuron.2009.04.008

Figure 2. Synaptic Bombardment in Active Cortical Networks In Vivo.

Figure 2

Illustrated are simultaneous recordings of the extracellular local field potential (LFP, top), the multiple unit activity (MU, middle), and intracellular membrane potential (bottom) from a cortical pyramidal cell during the generation of one Up state (bordered by two Down states). Note that the Up state is associated with a marked increase in local network activity, depolarization of the neuron (~25 mV), a marked increase in membrane potential variance (SD of Up = 2.5 mV), and the presence of higher-frequency (gamma, ~40 Hz) oscillations in the LFP. Periods of depolarization mediated by network activity provide “windows of opportunity” based upon increased neuronal gain and may be of long (example 1), medium (example 2), or short (example 3) duration. Thus, various frequency components of synaptic activity interact to initiate action potentials. Inset expands window 3, where the depolarizing half (~12.5 ms) of one full LFP oscillation cycle provides a short temporal window for the integration of both excitatory and inhibitory postsynaptic potentials (PSPs).