Central projections of the antennal cold receptor neurons and hygroreceptor neurons of the cockroach Periplaneta americana

Abstract

The central projections of the cold receptor axons were examined by filling two types of cold receptive sensilla with cobalt lysine--a cold and hygroreceptive (C/H) sensillum and a cold receptive and olfactory (C/O) sensillum--on the antennae of the cockroach, Periplaneta americana L. When the dye filled a single C/H sensillum, four axons were stained. Three of these axons terminate in the ipsilateral antennal lobe, while the other branches in the ipsilateral dorsal lobe. One of the branches passed through the tritocerebrum to terminate in the suboesophageal ganglion, while the other branches end in the lobe. When a single C/O sensillum is dye filled, all axons of the four receptor neurons terminate exclusively in the ipsilateral antennal lobe. One axon from the C/H sensillum and one axon from the C/O sensillum terminate in a particular glomerulus in the ventroposterior region of the antennal lobe. Each of these axons also has a tuft in separate glomeruli situated just dorsal to the glomerulus in which both axons terminate. This set of three glomeruli have indistinct boundaries and appear to form a complex of glomeruli similar to the macroglomerular complex of male moths. Assuming modality-specific convergence of antennal afferents, these axons appear to belong to the cold receptor neurons, and the set of glomeruli appear to function in cold reception. Two other neurons stained from C/H sensilla always terminate in the glom-eruli distinct from the set of glomeruli mentioned earlier. These neurons are assigned to the pair of hygroreceptor neurons, and their glomeruli are thought to function in hygroreception.

Myoinhibitory peptides in the brain of the cockroach Leucophaea maderae and colocalization with pigment‐dispersing factor in circadian pacemaker cells

“…In addition, specific sensory afferents targeting two glomeruli in the posterior antennal lobe of L. maderae might release MIPs. In P. americana, axons from cold and hygroreceptive sensilla terminate in four adjacent glomeruli in the ventroposterior region of the antennal lobe, termed DC1-3 (Nishikawa et al, 1995;Nishino et al, 2003), respectively J04, J05, J10, J11 (Watanabe et al, 2010). It is tempting to speculate that the two glomeruli stained here correspond to a subset of these glomeruli and that MIPs play a role as neuroactive substances released from coldreceptors or hygroreceptors.…”

Complete mapping of glomeruli based on sensory nerve branching pattern in the primary olfactory center of the cockroach Periplaneta americana

“…Immediately after entering the deutocerebrum, mechanosensory and contact-chemosensory afferents run posterodorsally and give off collaterals in the dorsal lobe and descend to the subesophageal ganglion to give off some terminal branches (Nishino et al, 2005). On the other hand, olfactory and hygrosensory and thermosensory afferents project to given glomeruli in the AL (Boeckh and Tolbert, 1993;Nishikawa et al, 1995;Mizunami, 2006, 2007;Nishino et al, 2009aNishino et al, , 2010. Some aspects of the structurerelated functional properties of the AL glomeruli have been reported for the cockroach (Burrows et al, 1982;Malun et al, 1993;Nishikawa et al, 1995;Strausfeld and Li, 1999;Nishino et al, 2003).…”

Serotonin-immunoreactive Neurons in the Antennal Sensory System of the Brain in the Carpenter Ant, Camponotus japonicus

“…In some insects, antennal sex-pheromone-sensitive neurons project into male-specific glomeruli, which are enlarged and called the macroglomerular complex or macroglomerulus (Boeckh and Tolbert, 1993;Hansson, 1999). In Periplaneta, antennal hygro-and thermosensory axons also project into several glomeruli, which are relatively large, ellipsoidal or crescent shaped, and restricted to the dorso-central region of the AL close to the DL (Nishikawa et al, 1995;Nishino et al, 2003). Five alarm pheromone-sensitive glomeruli have been identified in the dorsalmost part of the ventral cluster of the AL in the ant, C. obscuripes (Yamagata et al, 2006).…”