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. 1997 Jan 21;94(2):724–728. doi: 10.1073/pnas.94.2.724

Figure 4.

Figure 4

Illustration of the [Ca]i location during depolarization of a thalamic cell to the level of fast membrane potential oscillations. (A) Fura-2 control fluorescent image of an iontophoretically filled neuron. (B) [Ca]i image obtained from subtracting background fluorescence from recordings acquired during a depolarizing step to membrane potential level positive to the threshold for oscillation. Note the increase in [Ca]i at dendritic level. (C) Diagram of the proposed thalamocortical neuronal circuit depicting the somatic and dendritic calcium conductances in thalamic neurons. A thalamic projection neuron is shown synapsing on a pyramidal cell at layer IV. The return pathway to the thalamus terminates mostly on the dendritic compartments of TCNs, where dendritic high-threshold calcium-dependent oscillations are observed (red). The corticothalamic input gives collaterals to the reticular nucleus (green) reinforcing thalamocortical resonance by inhibitory reset.