Optical Imaging of Neural Activity

We use calcium imaging to explore the spatial dimension of neural processing in auditory and antennal interneurons, in afferents and in motor neurons. These cannot be revealed with single cell intracellular recordings. Local changes in calcium signals in dendrites and axons demonstrate the site of neural activation in single neurons and also the site of processing in neuronal networks and populations. We inject calcium reporters into neurons with microelectrodes and recently developed a method that allows electrophoretic delivery of calcium reporters into neurons through the sheath surrounding the nervous system. We are now in the process to develop and apply this method to different systems.

Cricket ON1 neuron (left) and its optical calcium signal during acoustic stimulation (right)

Watch and listen to the cricket Omega Neuron ON1 responding to sound stimuli, while changes in its cytosolic calcium signals are imaged: hear the neuron’s spike pattern and observe the changes in the optical calcium signal in dendrites and the axon.

Insect neurons are not only activated by the communication signals, but they will also respond to acoustic signals like music. Here the cricket has been exposed to the "Carmina Burana" and "Bolero", see how it responds.

Besides this the Omega Neuron also responds to funky pop:
https://www.youtube.com/watch?v=0c-sGm9dE2Q

References:

• Isaacson MD and Hedwig B. (2017) Neuroanatomical and functional labeling by tracer electrophoresis through the nerve sheath. Scientific Reports, 7:40433, DOI: 10.1038/srep40433
• Pulver SR, Bayley TG, Taylor AL, Berni J, Bate M, Hedwig B (2015) Imaging fictive locomotor patterns in larval Drosphila. J Neurophysiology, 114 (5):2564-2577, doi:10.1152/jn.00731.2015
• Baden T and Hedwig B (2010) Primary afferent depolarisation and frequency processing in auditory afferents. J Neurosci, 30:14862–14869
• Baden, T and Hedwig B (2006) Neurite specific Ca2+ dynamics underlying sound processing in an auditory interneurone. J Neurobiol 67: 68-80.
• Baden, T and Hedwig B (2009) Dynamics of free intracellular Ca2+ during synaptic and spike activity of cricket tibial motoneurons Europ J of Neurosci, 29: 1357–1368.