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-activated (HVA) barium currents was investigated in neurons of the deep cerebellar nuclei (DCN) by combining barium imaging with voltage clamp. The current-induced fluorescence signal (DeltaF/F) of the HVA current was five times higher then the LVA-induced signal at the soma, but both signals were approximately equal in size in distant dendrites. This position-dependent shift of DeltaF/F indicates a non-uniform distribution of the underlying calcium channels. The higher weight of the LVA signal in the dendrites suggests that the LVA might be of particular relevance for the dendritic integration of synaptic inputs.