title: Simultaneous measurement of membrane potential changes in multiple pattern generating neurons using voltage sensitive dye imaging.
abstract: Optical imaging using voltage-sensitive dyes (VSDs) is a promising technique for the simultaneous activity recording of many individual neurons. While such simultaneous recordings are critical for the understanding of the integral functionality of neural systems, functional interpretations on a single neuron level are difficult without knowledge of the connectivity of the underlying circuit. Central pattern generating circuits, such as the pyloric and gastric mill circuits in the stomatogastric ganglion (STG) of crustaceans, allow such investigations due to their well-known connectivities and have already contributed much to our understanding of general neuronal mechanisms. Here we present for the first time simultaneous optical recordings of the pattern generating neurons in the STG of two crustacean species using bulk loading of the VSD di-4-ANEPPS. We demonstrate the recording of firing activities and synaptic interactions of the circuit neurons as well as inter-circuit interactions in their functional context, i.e. without artificial stimulation. Neurons could be uniquely identified using simple event-triggered averaging. We tested this technique in two different species of crustaceans (lobsters and crabs), since several crustacean species are used for studying motor pattern generation. The signal-to-noise ratio of the optical signal was high enough in both species to derive phase-relationship between the network neurons, as well as action potentials and excitatory and inhibitory postsynaptic potentials. We argue that imaging of neural networks with identifiable neurons with well-known connectivity, like in the STG, is crucial for the understanding of emergence of network functionality.
authors.affiliation: Institute of Neurobiology, Ulm University, 89069 Ulm, Germany.
authors.forename: Carola
authors.initials: C
authors.lastname: Städele
authors.forename: Peter
authors.initials: P
authors.lastname: Andras
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Stein
mesh_terms: D000818:Animals; D003386:Brachyura; D005456:Fluorescent Dyes; D017952:Ganglia, Invertebrate / Q000502:physiology*; D008564:Membrane Potentials / Q000502:physiology*; D008121:Nephropidae; D009474:Neurons / Q000502:physiology*; D011726:Pyridinium Compounds; D056969:Voltage-Sensitive Dye Imaging / Q000379:methods*
chemical_list: D005456:Fluorescent Dyes; D011726:Pyridinium Compounds; C050019:1-(3-sulfonatopropyl)-4-(beta)(2-(di-n-butylamino)-6-naphthylvinyl)pyridinium betaine