Gerber B, Smith B H
Institut für Neurobiologie, Freie Universität Berlin, Königin-Luise-Strasse 28/30, Germany.
J Exp Biol. 1998 Jul;201(Pt 14):2213-7. doi: 10.1242/jeb.201.14.2213.
We use classical conditioning of the honeybee (Apis mellifera) proboscis extension reflex with a visual (A) and an olfactory (X) conditioned stimulus in a blocking paradigm. Typically, learning about one element (X) of a compound (AX) is decreased (blocked) if the other component (A) has previously been rewarded alone. Our results show that visual pretraining did not produce blocking in honeybees: instead, forward pairings of A with a reward increased subsequent learning about X relative to a backward pairing control. This finding violates the independence assumption, which holds that elements of inter-modal compound stimuli change associative strength independently of each other. Furthermore, it is at odds with common theories of conditioning that predict blocking and assume that the elements of a compound stimulus rely on one common internal reinforcing signal. Taking the functional anatomy of the honeybee brain into account, we suggest that vision and olfaction may not rely on the same internal reinforcing signal; compound interactions might thus reflect the wiring of the honeybee nervous system and the biological significance of different sensory modalities during natural behaviour.
我们在阻断范式中，利用视觉条件刺激（A）和嗅觉条件刺激（X）对蜜蜂（意大利蜜蜂）的喙伸展反射进行经典条件反射训练。通常情况下，如果复合刺激（AX）中的另一个成分（A）先前已单独得到奖励，那么对该复合刺激中一个成分（X）的学习就会减少（被阻断）。我们的研究结果表明，视觉预训练并未在蜜蜂中产生阻断效应：相反，相对于反向配对对照组，A与奖励的正向配对增加了随后对X的学习。这一发现违背了独立性假设，该假设认为跨模态复合刺激的各个成分彼此独立地改变联想强度。此外，这与预测会出现阻断效应并假设复合刺激的各个成分依赖于一个共同内部强化信号的常见条件反射理论不一致。考虑到蜜蜂大脑的功能解剖结构，我们认为视觉和嗅觉可能并不依赖于相同的内部强化信号；复合刺激之间的相互作用可能因此反映了蜜蜂神经系统的布线以及自然行为中不同感觉模态的生物学意义。
