Abstract
We examined dendritic activity in identified mechanosensory interneurons in the cricket cercal sensory system using Ca2+ imaging and intracellular recording techniques. Different dendritic branches of the interneurons displayed distinct directional sensitivity profiles to air-current stimuli. The amplitude of evoked spikes was larger at the dendritic branches in which the Ca2+ elevation was larger. Dual-site recordings of the dendritic spikes indicate that the spike-initiation site shifts depending on the location of the site of synaptic activation. We propose that a difference in spike-propagation direction could change the spike waveform at the distal dendrite and could produce synaptic activity-dependent Ca2+ dynamics.
