**10. Conclusions**

152 Zoology

Fig. 15. Responses of *BAL+* / *C15+ PNs* and *C15+ / BAL+ PNs* from male *Manduca sexta.* These MGC-PNs were depolarized by antennal stimulation with either BAL or C15. (A) This neuron responded with a strong response to C15 and a more sustained response to BAL (*C15+ / BAL+ PNs*). Stimulation with C15 also evoked a distinct IPSP (marked by asterisk) resulting in a mixed response (inhibition / excitation / inhibition). Varying the blend ratio changed the response character to more phasic or more tonic, depending on the load in the stimulus blend. (B) ISF response plots of a *C15+ / BAL+ PN* to various BAL and C15 stimulus loads and ratios revealed a sustained phasic-tonic response to C15 and a brief excitatory

This chapter details both extracellular and intracellular recording methods used with insect preparations in the fields of insect olfaction and/or gustation. Using one or both olfactory recording techniques contributes to a better understanding of (i) how and what olfactory information is processed in the insect brain, (ii) the chemical identification of important plant volatiles for insect-plant interactions, and (iii) which components of the female sex pheromone, as well as plant-associated volatiles, play important roles in male and female moth orientation, respectively. Complementing these recording techniques with the use of fluorescent markers allows axonal projections to be traced to the brain or central neurons to be labeled individually. Gustatory extracellular recording methods can ultimately (i) lead to a clearer understanding of the importance of gustatory cues involved in larval host-plant interactions, (ii) give us a better perception on how taste stimuli code for different behavioral responses, and (iii) provide ideas and strategies for crop protection from insect predation. Overall, either one or both of these methods (i.e., extracellular or intracellular) can contribute to an increased understanding of how and what chemosensory information is processed in the insect brain and shed more light on how nervous systems recognize, analyze, and respond to complex sensory information.
