Deisig N, Lachnit H, Giurfa M, Hellstern F
Neurobiology, Institute of Biology, Free University of Berlin, D-14195 Berlin, Germany.
Learn Mem. 2001 Mar-Apr;8(2):70-8. doi: 10.1101/lm.8.2.70.
In an appetitive context, honeybees (Apis mellifera) learn to associate odors with a reward of sucrose solution. If an odor is presented immediately before the sucrose, an elemental association is formed that enables the odor to release the proboscis extension response (PER). Olfactory conditioning of PER was used to study whether, beyond elemental associations, honeybees are able to process configural associations. Bees were trained in a positive and anegative patterning discrimination problem. In the first problem, single odorants were nonreinforced whereas the compound was reinforced. In the second problem, single odorants were reinforced whereas the compound was nonreinforced. We studied whether bees can solve these problems and whether the ratio between the number of presentations of the reinforced stimuli and the number of presentations of the nonreinforced stimuli affects discrimination. Honeybees differentiated reinforced and nonreinforced stimuli in positive and negative patterning discriminations. They thus can process configural associations. The variation of the ratio of reinforced to nonreinforced stimuli modulated the amount of differentiation. The assignment of singular codes to complex odor blends could be implemented at the neural level: When bees are stimulated with odor mixtures, the activation patterns evoked at the primary olfactory neuropile, the antennal lobe, may be combinations of the single odorant responses that are not necessarily fully additive.
在一个偏好性情境中，蜜蜂（西方蜜蜂）学会将气味与蔗糖溶液奖励联系起来。如果在蔗糖出现之前立即呈现一种气味，就会形成一种基本关联，使该气味能够引发伸吻反射（PER）。利用PER的嗅觉条件反射来研究蜜蜂除了基本关联之外，是否还能够处理构型关联。蜜蜂接受了正向和负向模式辨别问题的训练。在第一个问题中，单一气味剂不给予强化，而复合气味剂给予强化。在第二个问题中，单一气味剂给予强化，而复合气味剂不给予强化。我们研究了蜜蜂是否能够解决这些问题，以及强化刺激呈现次数与非强化刺激呈现次数之间的比例是否会影响辨别。蜜蜂在正向和负向模式辨别中区分了强化和非强化刺激。因此，它们能够处理构型关联。强化与非强化刺激比例的变化调节了辨别程度。在神经层面可以实现为复杂气味混合物分配单一编码：当用气味混合物刺激蜜蜂时，在主要嗅觉神经纤维网即触角叶诱发的激活模式可能是单一气味剂反应的组合，而这些组合不一定是完全相加的。
