Department of Zoology, Stockholm University, Svante Arrheniusväg 18 B, Stockholm, Sweden.
Proc Biol Sci. 2022 Jul 13;289(1978):20220844. doi: 10.1098/rspb.2022.0844.
Determining how variation in brain morphology affects cognitive abilities is important to understand inter-individual variation in cognition and, ultimately, cognitive evolution. Yet, despite many decades of research in this area, there is surprisingly little experimental data available from assays that quantify cognitive abilities and brain morphology in the same individuals. Here, we tested female guppies () in two tasks, colour discrimination and reversal learning, to evaluate their learning abilities and cognitive flexibility. We then estimated the size of five brain regions (telencephalon, optic tectum, hypothalamus, cerebellum and dorsal medulla), in addition to relative brain size. We found that optic tectum relative size, in relation to the rest of the brain, correlated positively with discrimination learning performance, while relative telencephalon size correlated positively with reversal learning performance. The other brain measures were not associated with performance in either task. By evaluating how fast learning occurs and how fast an animal adjusts its learning rules to changing conditions, we find support for that different brain regions have distinct functional correlations at the individual level. Importantly, telencephalon size emerges as an important neural correlate of higher executive functions such as cognitive flexibility. This is rare evidence supporting the theory that more neural tissue in key brain regions confers cognitive benefits.
确定大脑形态的变化如何影响认知能力对于理解个体间认知差异以及认知进化至关重要。然而，尽管在这一领域进行了几十年的研究，但在量化同一个体认知能力和大脑形态的实验数据方面，仍然非常有限。在这里，我们在两项任务中测试了雌性孔雀鱼（），以评估它们的学习能力和认知灵活性。然后，我们估计了五个大脑区域（端脑、视顶盖、下丘脑、小脑和背髓）的大小，以及相对大脑大小。我们发现，相对于大脑的其他部分，视顶盖的相对大小与辨别学习表现呈正相关，而相对端脑的大小与反转学习表现呈正相关。其他大脑测量指标与两种任务的表现均无关。通过评估学习速度和动物调整学习规则以适应变化条件的速度，我们发现不同的大脑区域在个体水平上具有不同的功能相关性。重要的是，端脑大小是高级执行功能（如认知灵活性）的重要神经相关物。这是支持关键大脑区域中更多神经组织赋予认知益处的理论的罕见证据。
