Comparative animal studies of complex behavioural traits, and their neurobiological underpinnings, can increase our understanding of their evolution, including in humans. Vocal learning, a potential precursor to human speech, is one such trait. Mammalian vocal learning is under-studied: most research has either focused on vocal learning in songbirds or its absence in non-human primates. Here, we focus on a highly promising model species for the neurobiology of vocal learning: grey seals (Halichoerus grypus). We provide a neuroanatomical atlas (based on dissected brain slices and magnetic resonance images), a labelled MRI template, a three-dimensional model with volumetric measurements of brain regions, and histological cortical stainings. Four main features of the grey seal brain stand out: (i) it is relatively big and highly convoluted; (ii) it hosts a relatively large temporal lobe and cerebellum; (iii) the cortex is similar to that of humans in thickness and shows the expected six-layered mammalian structure; (iv) there is expression of FoxP2 present in deeper layers of the cortex; FoxP2 is a gene involved in motor learning, vocal learning, and spoken language. Our results could facilitate future studies targeting the neural and genetic underpinnings of mammalian vocal learning, thus bridging the research gap from songbirds to humans and non-human primates. Our findings are relevant not only to vocal learning research but also to the study of mammalian neurobiology and cognition more in general.

This article is part of the theme issue ‘Vocal learning in animals and humans’.

对复杂行为特征及其神经生物学基础的比较动物研究可以增加我们对它们进化的理解，包括在人类中的进化。声乐学习是人类语音的潜在先驱，就是这样一种特征。哺乳动物的声乐学习研究不足：大多数研究要么集中在鸣禽的声乐学习上，要么集中在非人类灵长类动物的声乐学习上。在这里，我们专注于一个非常有前途的声音学习神经生物学模型物种：灰海豹（Halichoerus grypus）。我们提供神经解剖图谱（基于解剖的脑切片和磁共振图像）、标记的 MRI 模板、具有脑区域体积测量的 3D 模型和组织学皮质染色。灰海豹大脑有四个主要特征：（i）它相对较大且高度复杂；(ii) 它拥有相对较大的颞叶和小脑；(iii) 皮层的厚度与人类相似，并显示出预期的六层哺乳动物结构；(iv) FoxP2 的表达存在于皮层的更深层；福克斯P2是一种参与运动学习、声音学习和口语的基因。我们的结果可以促进未来针对哺乳动物声音学习的神经和遗传基础的研究，从而弥合从鸣禽到人类和非人类灵长类动物的研究差距。我们的发现不仅与声音学习研究相关，而且更普遍地与哺乳动物神经生物学和认知研究相关。

这篇文章是主题问题“动物和人类的声乐学习”的一部分。