Spatial distribution of low- and high-voltage-activated calcium currents in neurons of the deep cerebellar nuclei

The spatial distribution of low-voltage-activated (LVA) and high-voltage-ac tivated (HVA) barium currents was investigated in neurons of the deep cereb ellar nuclei (DCN) by combining barium imaging with voltage clamp. The curr ent-induced fluorescence signal (DeltaF/F) of the HVA current was five time s higher then the LVA-induced signal at the soma, but both signals were app roximately equal in size in distant dendrites. This position-dependent shif t of DeltaF/F indicates a non-uniform distribution of the underlying calciu m channels. The higher weight of the LVA signal in the dendrites suggests t hat the LVA might be of particular relevance for the dendritic integration of synaptic inputs.