Sigg D, Thompson C M, Mercer A R
Department of Zoology, University of Otago, Dunedin, New Zealand.
J Neurosci. 1997 Sep 15;17(18):7148-56. doi: 10.1523/JNEUROSCI.17-18-07148.1997.
To explore the origins and possible behavioral consequences of structural plasticity in an insect brain, we have taken advantage of the following: (1) the highly compartmentalized nature of the primary antenno-sensory centers (antennal lobes) of the brain, (2) the ease with which individual compartments, or glomeruli, within the antennal-lobe neuropil can be identified, and (3) the predictability of changes to readily identifiable glomeruli in the antennal lobes of the adult worker honey bee. Treatment with the juvenile hormone analog methoprene and hive manipulation techniques are used to induce precocious foraging behavior in young worker honey bees. The impact of these treatments on the ontogeny of olfactory learning performance and on the volumes of readily identifiable glomeruli in the antennal lobes of the bee brain are examined in parallel. The study reveals that (1) significant changes in glomerular volume are activity dependent and (2) associative learning of floral odors improves with experience. Improvements in associative learning performance coincide temporally with increases in glomerular volume. This raises an important question: are changes in glomerular volume that result from shifts in behavior simply a consequence of changes in the use of peripheral sensory pathways, or are they associated with events that underlie learning and the formation of long-term memories?
为了探究昆虫大脑中结构可塑性的起源及其可能的行为后果，我们利用了以下几点：（1）大脑初级触角感觉中枢（触角叶）高度分隔的特性；（2）触角叶神经纤维网内各个分隔区域，即嗅觉小球，易于识别；（3）成年工蜂触角叶中易于识别的嗅觉小球变化具有可预测性。使用保幼激素类似物烯虫酯处理和蜂巢操纵技术来诱导年轻工蜂早熟的觅食行为。同时研究这些处理对嗅觉学习能力个体发育以及蜜蜂大脑触角叶中易于识别的嗅觉小球体积的影响。研究表明：（1）嗅觉小球体积的显著变化依赖于活动；（2）对花香气味的联想学习能力会随着经验的增加而提高。联想学习能力的提高在时间上与嗅觉小球体积的增加相一致。这就引出了一个重要问题：行为改变导致的嗅觉小球体积变化仅仅是外周感觉通路使用变化的结果，还是与学习及长期记忆形成背后的事件有关？
