CHEMOSENSORY INTEGRATION IN THE SPINY LOBSTER - ASCENDING ACTIVITY IN THE OLFACTORY-GLOBULAR TRACT

Chemical stimulation of the antennules (1st antennae) of the spiny lobster, Panulirus argus, activates olfactory-globular tract neurons that ascend the eyestalk of this organism. Extracellular records show that: 1. Receptor fields of these neurons are always unilateral. Fields of some units include medial as well as lateral filament chemoreceptors. Ipsilateral input predominates but some crossing over of contralateral input is evident (Table 1). 2. These neurons respond to antennular chemostimulation with a transient, concentration-dependent increase in firing frequency (Fig. 3). No inhibitory responses were noted. Thresholds to taurine stimulation average 2.4×10-5M (Table 3). 3. Responses decrement rapidly to repetitive stimulation (Fig. 4). Responses are not decremented or incremented by simultaneous bilateral chemostimulation (Table 4). The results indicate interneuron status for the units described. The lack of evidence for spatial and/or temporal integration of olfactory information ascending the eyestalk supports the earlier contention that the distal eyestalk ganglia are the site of spatio/temporal processing of antennular chemosensory afference re the initiation of feeding behavior in this organism. © 1979 Springer-Verlag.