online: J Comp Physiol A, DOI 10.1007/s003590000156; http://link.springer.de/link/service/journals/00359/contents/00/00156/
Calcium responses to pheromones and plant odors in the antennal lobe of the male and female moth Heliothis virescensCG Galizia, S Sachse, H Mustaparta
Inst. Biologie - Neurobiologie, Fachbereich BioChemPharm, Freie Universität Berlin, D-14195 Berlin, Germany
Department of Zoology, Norwegian University of Science and Technology, NTNU, N-7194 Trondheim, Norway
Abstract
In male moths, the primary olfactory integration centre, the antennal lobe, consists of two systems. The macroglomerular complex (MGC) processes pheromone information, while the ordinary glomeruli process plant odor information. Females lack an MGC.
We measured the spatial representation of odors using in-vivo optical recording. We found that: 1) pheromone substances elicited activity exclusively in the MGC. No response was found in female antennal lobes. 2) Plant odors elicited combinatorial activity patterns in the ordinary glomeruli in both males and females. No response was found in the MGC of male moths. 3) A clean air puff often led to activity, in both males and females, suggesting that mechano-sensory information is also processed in the antennal lobe. 4) With an inter-stimulus interval of 5 or 10s, strongly activated glomeruli were able to follow the temporal structure of the stimulus, while others lost their phase-locking. Some glomeruli showed 'off' responses. These properties were odor-dependent.
This confirms and extends previous studies, showing the functional significance of the two subsystems for processing olfactory information. Pheromones are coded in a combinatorial manner within the MGC, with each glomerulus corresponding to one information channel. Plant odors are coded in an across-glomeruli code in the ordinary glomeruli.