Phase Relationships between Calcium and Voltage Oscillations in Different Dendrites of Purkinje Neurons

We address the spatial dynamics of the membrane potential and intracellular Ca 2+ concentration in the dendritic arborization of a simulated Purkinje neuron reconstructed at a high spatial resolution. We probe the mechanisms that couple spatial patterns of steady-state and oscillatory plateau potentials and Ca 2+ dynamics with the dendritic geometry. Simulations were performed with both passive and active membranes. Steady currents applied to the soma produced heterogeneous voltage distributions revealing the geometry-linked features of voltage and current transfer in the dendrite. Branching asymmetry split the isoplanar dendritic field into domains of different efficiencies. Active dendrites equipped with P-type Ca 2+ , delayed rectifier K + , A-type K + , high-threshold Ca-activated K + channels, and intracellular Ca 2+ ([Ca 2+ ] i ) dynamic mechanisms reproduced oscillatory plateau potentials. Occurring at given intensities of homogeneous tonic excitation via AMPA-type synapses over the whole arborization, the oscillatory activity of the dendritic domains is phase-ordered. An advance or a lag in the phase correlated with a lower or higher steady-transfer effectiveness of the corresponding domains. Snapshots of the dendritic field during plateau potentials reveal the dynamics of dendritic domains with different membrane potentials and [Ca 2+ ] i , which are spatially reconfigured according to the phase of the cycle. This complex spatio-temporal behavior is hidden in single-site recordings.