Smulders T V, Shiflett M W, Sperling A J, DeVoogd T J
Department of Psychology, Uris Hall, Cornell University, Ithaca, New York, USA.
J Neurobiol. 2000 Sep 15;44(4):414-22. doi: 10.1002/1097-4695(20000915)44:4<414::aid-neu4>3.0.co;2-i.
The volume of the hippocampal formation (HF) in black-capped chickadees (Poecile atricapillus) varies across the seasons, in parallel with the seasonal cycle in food hoarding. In this study, we estimate cell density and total cell number in the HF across seasons in both juveniles and adults. We find that the seasonal variation in volume is due to an increase in the number of small and large cells (principally neurons) in the fall. Adults also have lower neuron densities than juveniles. Both juveniles and adults show an increase in cell density in the rostral part of the HF in August and a subsequent decrease toward October. This suggests that the net cell addition to the HF may already start in August. We discuss the implications of this early start with respect to the possibility that the seasonal change in HF volume is driven by the experience of food hoarding. We also speculate on the functional significance of the addition of neurons to the HF in the fall.
黑头山雀（Poecile atricapillus）海马结构（HF）的体积随季节变化，与食物储存的季节性周期同步。在本研究中，我们估计了幼鸟和成鸟整个季节HF中的细胞密度和细胞总数。我们发现，体积的季节性变化是由于秋季小细胞和大细胞（主要是神经元）数量增加所致。成鸟的神经元密度也低于幼鸟。幼鸟和成鸟在8月时HF喙部的细胞密度均增加，随后在10月下降。这表明HF的净细胞增加可能在8月就已开始。我们讨论了这种早期开始对于HF体积季节性变化由食物储存经验驱动这一可能性的影响。我们还推测了秋季向HF添加神经元的功能意义。
