Electrophysiological analysis of synaptic interactions within peg sensilla of scorpion pectines

Abstract

Pectines are unique, midventral sensory appendages that help direct mating and food-finding behaviors in scorpions. Dense two-dimensional arrays of bimodally sensitive (chemical and mechanical) peg sensilla form the primary sensory structures on pectines. Several qualities of peg sensilla make them well suited to electrophysiological investigation, including accessibility, stability of extracellular recordings, and the ease with which spiking cells can be identified and categorized. Cross-correlations of spontaneous neural activity show signs of synaptic interactions between sensillar neurons in all species examined to date (Paruroctonus mesaensis, Hadrurus arizonensis, Centruroides vittatus) representing three families and two superfamilies. Both excitatory and inhibitory interactions have been observed, as well as possible dyadic synaptic arrangement. Computer simulations of cross-correlograms are consistent with experimental data and may help provide additional insight into functionality of synaptic connections. Intra-sensillar interactions, coupled with the topographic order of peg sensilla and their central nervous system projections, may allow scorpions to precisely resolve microfeatures of chemical stimuli. Future research directions include inter-sensillar recordings to determine whether synaptic interactions extend between adjacent sensilla. Other unresolved questions that can be approached electrophysiologically are whether mechanosensory cells interact with chemosensitive cells and how the synaptic circuits function under specific chemical and mechanical stimulation.

Non-synaptic inhibition between grouped neurons in an olfactory circuit

“…Third, we tested the possibility of axo-axonic synapses between ORNs with a cross-correlation analysis 32 . Analysis of ab3A and ab3B spontaneous spikes did not reveal coordinated spiking patterns and thus provided no evidence for axo-axonic synaptic interactions (Fig.…”

Development of respiratory structures in embryos and first and second instars of the bark scorpion, Centruroides gracilis (Scorpiones: Buthidae)

“…18). The pectines in adult scorpions have been shown to be a complex chemo-and mechanosensory organ (Foelix and Mü ller-Vorholt, 1983;Fet and Brownell, 1998;Brownell, 1998Brownell, , 2001Gaffin and Brownell, 1992, 1997a,b, 2001Gaffin, 2001Gaffin, , 2002Mineo and Del Claro, 2006). Phylogenetic differences in the structure of the pectines and peg sensilla (see Fig.…”

Mesobuthus gibbosus (Brullé, 1832) (Scorpiones: Buthidae) Akrep Türünün Tarak Organının Fonksiyonel Morfolojisi ve Histolojisi

“…Ancak literatürde bu konuda herhangi bir kayıta rastlanmamıştır. Gaffin (2002) yaptığı çalışmada her bir peg sensilliumun uç kısmında yarık şeklinde bir pora sahip olduğunu belirtmiştir. Gerek SEM gerekse ışık mikroskobu bulgularımızda yarık şeklindeki bu porlar netlikle görülmüştür.…”

“…Kladt ve arkadaşları (2007), Pandinus cavimanus akrep türünde tarak organı üzerindeki kütikülar sensillaların mekanoreseptör olarak görev yaptığı belirtmiştir. Gaffin (2002) Pektin organlar üzerinde yine çok sayıda duyusal kıllar gözlenmiştir (Şekil 3A, B). Tarak organın marjinal lamellasında ve median lamellasında olmak üzere iki farklı kısmında bu kıllar yaygın şekilde görülmüştür (Şekil 4A).…”