Development of hemispheric specialization pattern, a model of ontogenetic plasticity

大脑偏侧化，即一侧大脑对特定功能的支配，是动物界神经元信息处理的核心特征，表明当大脑显示出两个大脑一半之间的分工时，具有深刻的健康优势。侧化处理基于复杂的半球内和半球间机制，支持独立的、半球特定的编码，但也支持信息的交换、整合或抑制。关于合作或独立加工的基本职能组织及其发展，人们知之甚少。因此，本项目提案的目的是了解两个专门的大脑半部分如何沟通，产生适应性决定和行为控制，以及发育过程中的基因-环境相互作用如何塑造潜在的大脑半球内和大脑间过程。我们以鸽子非对称组织的视觉系统为模型来研究环境因素光的影响，因为视觉不对称的出现依赖于胚胎发育过程中的偏向视觉刺激。特别是，研究冲突情境中反应选择的任务(元控制)使我们能够探索大脑半球内和大脑间过程的相关性，促进了大脑半球特有的专门神经元回路的动态使用。我们想通过三组实验来解决这个问题，比较有和没有胚胎光经验的鸽子的元控制模式：实验I调查冲突选择中半球优势的出现在多大程度上依赖于胚胎光刺激。实验二解决了刺激分析的偏侧化模式在多大程度上依赖于个体发生光经验的问题，并探索了元控制与大脑半球加工专门化相关的动态性和灵活性。实验三旨在通过光遗传学来揭示大脑半球支配冲突决策的神经元机制。我们的研究可以提供重要的线索，即个体发生感觉体验如何影响两个大脑一半之间的有效互动。这可能会极大地提高我们对大脑偏侧的认知优势的理解，但也会对发育和精神障碍的损害有所帮助。

Cerebral lateralization, the dominance of one brain side for a specific function, is a core feature of neuronal information processing in the animal kingdom indicating a profound fitness advantage when brains display a division of labour between the two brain halves. Lateralized processing is based on complex intra- and interhemispheric mechanisms enabling independent, hemispheric-specific encoding but also exchange, integration, or suppression of information. The underlying functional organization of cooperative or independent processing as well as its development is only poorly understood. It is therefore the aim of this project proposal to understand how two specialized brain halves communicate generating adaptive decisions and behavioural control and how gene-environment interactions during development shape the underlying intra- and interhemispheric processes. We use the asymmetrically organized visual system of pigeons as a model to investigate the impact of the environmental factor light since the emergence of visual asymmetries depend on biased visual stimulation during embryonic development. Especially tasks investigating response selection in conflict situations (metacontrol) enable us to probe the relevance of intra- and interhemispheric processes facilitating a dynamic use of hemispheric-specific specialized neuronal circuits. We want to address this topic by three sets of experiments comparing metacontrol pattern of pigeons with and without embryonic light experience:Experiment I investigates in how far the emergence of hemispheric dominance in conflict choices depends on embryonic light stimulation. Experiment II addresses the question in how far a lateralized mode of stimulus analysis depends on ontogenetic light experience and explores the dynamics and flexibility of metacontrol in relation to hemispheric processing specializations. Experiment III aims for unravelling the neuronal mechanisms underlying hemispheric dominance in conflict decisions by means of optogenetics.Our studies can provide important hints how ontogenetic sensory experience impacts efficient interactions between the two brain halves. This may crucially improve our understanding the cognitive advantages of a lateralized brain but also impairments in developmental and psychiatric disorders.