Balling A, Technau G M, Heisenberg M
J Neurogenet. 1987 Apr;4(2-3):65-73.
The pre-imaginal development of Drosophila mushroom bodies is under the influence of an unknown variable which causes populations of wild-type flies at eclosion to differ in the average number of Kenyon cell fibers. During the first week of adult life the number of adjusts to an intermediate level which depends upon the experience of the flies. Under olfactory deprivation or social isolation it reaches a lower level than under favorable rearing conditions (J. Neurogenet., 1 (1984) 113-126). The biochemical learning mutants dunce and rutabaga show no experience-dependent modulation of fiber number. In both strains the mushroom bodies of young adults seem to develop abnormally: in dunce a loss of about 600 fibers is observed, in rutabaga fiber number is low at eclosion and does not increase. The following model for long-term memory is proposed: in mushroom bodies outgrowth and decay of Kenyon cell fibers occur simultaneously. The fibers randomly form transient synapses onto extrinsic output neurons of the mushroom bodies and receive synapses from modulating neurons. Experience consolidates certain synapses, thus prolonging survival of the respective Kenyon cell fibers and increasing the steady state level of fiber number.
果蝇蘑菇体的成虫前期发育受一个未知变量的影响，该变量导致羽化时的野生型果蝇群体在肯扬细胞纤维的平均数量上存在差异。在成虫生命的第一周，其数量会调整到一个取决于果蝇经历的中间水平。在嗅觉剥夺或社会隔离的情况下，它会达到比在良好饲养条件下更低的水平（《神经遗传学杂志》，1（1984）113 - 126）。生化学习突变体“笨蛋”和“大头菜”未表现出纤维数量的经验依赖性调节。在这两个品系中，年轻成虫的蘑菇体似乎发育异常：在“笨蛋”品系中，观察到约600根纤维缺失，在“大头菜”品系中，羽化时纤维数量较低且不增加。提出了以下长期记忆模型：在蘑菇体中，肯扬细胞纤维的生长和衰退同时发生。这些纤维随机地在蘑菇体的外在输出神经元上形成瞬时突触，并接受调节神经元的突触。经验巩固了某些突触，从而延长了相应肯扬细胞纤维的存活时间，并提高了纤维数量的稳态水平。
