Neurological adaptation and ecological specialisation

我们生活在感官信息的杂音中。理解我们生活的环境是大脑的工作。它必须提取最相关的线索，并将这些信息与过去经历的记忆结合起来，以触发适当的行为反应。对于生活在不同环境中的动物来说，最可靠的感官信息可能来自不同的来源，它们的经历可能会有所不同，什么是适当的行为可能会完全不同。因此，大脑必须进化，以满足不断变化的环境的需求。我的研究询问大脑如何适应适应性变化，这些变化是如何产生的，以及为什么一种进化解决方案比另一种更受青睐。150多年来，生物学家一直在研究拟态蝴蝶，以洞察其进化过程。当远亲物种聚集在相同的颜色模式上，警告捕食者它们是有毒的，需要避免的时候，模仿就会进化。这具有戏剧性的连锁反应，促使栖息地偏好、感觉环境、觅食和生殖行为发生变化。在许多情况下，这会导致蝴蝶进化成看起来相同、行为相似、栖息地相似的蝴蝶。这使它们成为研究大脑功能和进化的理想系统，因为它们在行为上是不同的，相同的行为已经进化了多次。我的项目利用这些特征来探索随着物种分化到不同的环境，大脑结构是如何变化的。我将测量大脑中具有不同功能的不同组成部分的大小，例如在视觉、嗅觉或记忆方面。它们的相对大小的变化意味着该功能的重要性的变化。因此，通过比较不同物种的大脑，我可以确定它们在结构上的差异，这些差异反映了对一个物种环境的特殊需求的适应。然后我会问这些变化是如何发生的：它们是基因变化的结果还是大脑发育方式的灵活性？细胞水平的变化如何改变大脑处理和存储信息的方式？了解大脑是如何进化的，对于理解动物王国中观察到的各种行为是至关重要的，动物王国是生物多样性的主要轴心。它还可以告诉我们，动物能够以多快的速度改变自己的行为，以应对快速的环境变化，这是否需要对遗传编码的适应进行选择，或者是否可以通过大脑和行为发展方式的灵活性来促进这一点。进化比较也为理解大脑功能的一般问题提供了有洞察力的模型。例如，哪些类型的细胞对大脑大小的变化有贡献？大脑发育是如何控制的？不同的脑细胞是如何相互连接和交流的？这可以告诉我们我们自己的生物学，以及这些发育过程中断导致的疾病的起源。我将通过关注物种感知和记忆环境信息的具体变化来解决这些问题。例如，我之前已经证明，在西番莲蝴蝶中，有一个名为蘑菇体的大脑区域的大小增加了两倍。蘑菇体与学习和记忆有关，这种爆炸性的扩张可能与这些物种在环境中导航的技能有关。昆虫蘑菇体在遗传控制和功能组织方面的相似性使其直接与哺乳动物的前脑相提并论，为研究细胞增殖和交流的一般原理提供了一个新的框架。通过考虑蘑菇体如何在多个生物水平上发生扩张，从基因到细胞，再到行为和生态，我将调查这些不同规模的过程是如何相互作用，以促进或限制大脑功能的方式。

We live amidst a cacophony of sensory information. It is the job of the brain to make sense of the environment we live in. It must extract the most relevant cues and combine this information with memories of past experiences to trigger appropriate behavioural responses. For animals living in different environments the most reliable sensory information may come from different sources, the experiences they have may vary, and what passes as appropriate behaviour can be radically different. The brain must therefore evolve to meet the demands of a changing environment. My research asks how brains accommodate adaptive change, how these changes are brought about, and why one evolutionary solution is favoured over another. For over 150 years biologists have studied mimetic butterflies to gain insights into the evolutionary process. Mimicry evolves when distantly related species converge on the same colour pattern to warn predators that they are toxic and to be avoided. This has dramatic knock-on effects, driving changes in habitat preference, sensory environment, foraging and reproductive behaviour. In many cases it results in butterflies that evolved to look the same also behaving in similar ways and occupying similar habitats. This makes them an ideal system to study how brains function and evolve because they are behaviourally diverse and the same behaviours have evolved multiple times.My project leverages these features to explore how brain structure changes as species diverge into different environments. I will measure the size of distinct components of the brain that have different functions, for example in vision, olfaction or memory. Changes in their relative size imply a change in the importance of that function. By comparing brains of different species I can therefore identify differences in their structure that reflect adaptations to the particular demands of a species' environment. I will then ask how these changes occur: are they are the result of genetic changes or flexibility in the way the brain develops? And how do changes at the cellular level alter the way the brain processes and stores information? Understanding how brains evolve is central to understanding the diverse range of behaviour observed in the animal kingdom, a major axis of biodiversity. It can also tell us how quickly animals are able to change their behaviour to respond to rapid environmental change, and whether this requires selection for genetically-encoded adaptations, or if it can be facilitated by flexibility in the way brains and behaviour develop. Evolutionary comparisons also provide insightful models for general problems in understanding brain function. For example, what types of cells contribute to changes in brain size? How is brain development controlled? And how do different brain cells connect and communicate with one another? This can tell us about our own biology, and the origin of disorders caused by disruption of these developmental processes.I will tackle these questions by homing in on specific changes in the way species perceive and remember information about their environment. For example, I have previously shown that one brain region, called the mushroom body, has trebled in size in passion-vine butterflies. The mushroom bodies are implicated in learning and memory, and this explosive expansion may be linked to the skill with which these species navigate their environment. Similarities in the genetic control and functional organisation of the insect mushroom body make it directly comparable to the mammalian forebrain, providing a novel framework for studying general principles in cell proliferation and communication. By considering how mushroom body expansion occurred at multiple biological levels, from genes to cells to behaviour and ecology, I will investigate how processes at these different scales interact to facilitate, or restrict, the way brains function.