Dendritic Ca2+ dynamics and multimodal processing in a cricket antennal interneuron.

The integration of stimuli of different modalities is fundamental to information processing within the nervous system. A descending interneuron in the cricket brain, with prominent dendrites in the deutocerebrum, receives input from three sensory modalities: touch of the antennal flagellum, strain of the antennal base, and visual stimulation. Using calcium imaging, we demonstrate that each modality drives a Ca2+ increase in a different dendritic region. Moreover, touch of the flagellum is represented in a topographic map along the neuron's dendrites. Using intracellular recording, we investigated the effects of Ca2+ on spike shape through the application of the Ca2+ channel antagonist Cd2+ and identified probable Ca2+-dependent K+ currents. NEW & NOTEWORTHY Different dendritic regions of the cricket brain neuron DBNi1-2 showed localized Ca2+ increases when three modalities of stimulation (touch of the flagellum, strain at antennal base, and visual input) were given. Touch stimulation induces localized Ca2+ increases according to a topographic map of the antenna. Ca2+ appears to activate K+ currents in DBNi1-2.