Data from: Effects of maternal age and environmental enrichment on learning ability and brain size

It is well known that maternal age at reproduction affects offspring
lifespan and some other fitness-related traits, but it remains
understudied whether maternal senescence affects how offspring respond to
their environments. Early environment often plays a significant role in
the development of an animal’s behavioral phenotype. For example, complex
environments can promote changes in cognitive ability and brain morphology
in young animals. Here, we study whether and how maternal effect
senescence influences offspring plasticity in cognition, group behavior,
and brain morphology in response to environmental complexity. For this,
juvenile three-spined sticklebacks from young and old mothers (i.e. 1-year
and 2-years-old) were exposed to different levels of environmental
enrichment and complexity (i.e. none, simple and complex), and their
behavior, cognitive ability, and brain size were measured. Exposing fish
to enriched conditions improved individual learning ability assessed by a
repeated detour-reaching task, increased the size of the whole brain, and
decreased aggressive interactions in the shoal. Maternal age did not
influence the inhibitory control, learning ability, and group behavioral
responses of offspring to the experimental environmental change. However,
maternal age affected how some brain regions of offspring changed in
response to environmental complexity. In offspring from old mothers, those
exposed to the complex environment had larger telencephalons and
cerebellums than those who experienced simpler environments. Our results
suggest that maternal effect senescence may influence how offspring invest
in brain functions related to cognition in response to environmental
complexity.

众所周知，繁殖时的母本年龄（maternal age at reproduction）会影响后代寿命及其他若干适应性相关性状（fitness-related traits），但母本衰老（maternal senescence）是否影响后代对环境的响应仍有待深入研究。
早期环境通常对动物行为表型（behavioral phenotype）的发育起重要作用。例如，复杂环境可促进幼龄动物认知能力（cognitive ability）与脑形态（brain morphology）的改变。
在此，我们研究母本效应衰老（maternal effect senescence）是否及如何影响后代在认知、群体行为及脑形态方面对环境复杂性的可塑性（plasticity）。
为此，我们将来自年轻（1岁）与年老（2岁）母本的三刺鱼（three-spined sticklebacks）幼鱼暴露于不同程度的环境富集与复杂性（environmental enrichment and complexity）条件下（即无富集、简单富集、复杂富集），并测量其行为、认知能力及脑大小。
结果显示，暴露于富集环境可提升个体通过重复绕道取食任务（repeated detour-reaching task）评估的学习能力，增大全脑尺寸，并减少鱼群中的攻击互动。
母本年龄不影响后代对实验环境变化的抑制控制（inhibitory control）、学习能力及群体行为反应。然而，母本年龄会影响后代某些脑区对环境复杂性的响应变化。
在年老母本的后代中，暴露于复杂环境者的端脑（telencephalons）与小脑（cerebellums）尺寸显著大于经历简单环境者。
我们的研究结果表明，母本效应衰老可能影响后代在响应环境复杂性时对认知相关脑功能的资源投入。