Operant conditioning of antennal muscle activity in the honey bee (Apis mellifera L.)

Antennal movements of the honey bee can be conditioned operantly under labo ratory conditions. Using this behavioural paradigm we have developed a prep aration in which the activity of a single antennal muscle has been operantl y conditioned. This muscle, the fast flagellum flexor muscle, is innervated by an identified motoneuron whose action potentials correlate 1:1 with the muscle potentials. The activity of the fast flagellum flexor muscle was re corded extracellularly from the scapus of the antenna. The animal was rewar ded with a drop of sucrose solution whenever the muscle activity exceeded a defined reward threshold. The reward threshold was one standard deviation above the mean spontaneous frequency prior to conditioning. After ten condi tioning trials, the frequency of the muscle potentials had increased signif icantly compared to the spontaneous frequency. The conditioned changes of f requency were observed for 30 min after conditioning. No significant change s of the frequency were found in the yoke control group. The firing pattern of the muscle potentials did not change significantly after conditioning o r feeding. Fixing the antennal joints reduces or abolishes associative oper ant conditioning. The conditioned changes of the frequency of muscle potent ials in the freely moving antenna are directly comparable to the behavioura l changes during operant conditioning.