In tthis project, funded by the ANR (APITASTE) we investigate mechanisms of central gustatory processing in the brain of an insect model in which taste encoding has remained unexplored. Using calcium imaging, we aim at characterize gustatory maps in the SEZ and determine whether they follow a hedonic-principle organization. We couple in vivo imaging of the SEZ with a novel protocol of gustatory conditioning in immobilized bees in order to determine how neural taste representation varies with aversive learning and with different phases of memory formation. We aim at decrypting central-taste neuromodulation by focusing on the facilitatory or inhibitory effects of biogenic amines and sNPF, for which receptors have been characterized in the bee genome.
The specific objectives addressed in this project are:
• Imaging the SEZ during gustatory stimulation of the antennae and mouth parts of immobilized bees using calcium imaging; determining the nature of gustatory maps in the SEZ and their organization principles. We will determine the principles of taste regionalization (if any) within the SEZ both for the structural and hedonic nature of tastants, as well as for the appendages that detects them.
• Coupling in vivo calcium imaging of the SEZ with aversive gustatory conditioning of the sting extension response in immobilized bees. We will monitor dynamic changes of taste representations in vivo in a conditioned bee to determine if and how neural representations of taste vary with aversive learning and memory formation.
• Assessing if and how neuromodulation affects central taste processing and salience. We will determine the role of biogenic amines such as dopamine (DA), octopamine (OA), tyramine (TYR) and serotonin (5HT), and of sNPF in taste encoding via RNAi receptor blockade and upregulation of these different forms of signaling in the SEZ.