Development of hemispheric specialization pattern, a model of ontogenetic plasticity

大脑侧化，即一侧大脑在特定功能上占主导地位，是动物王国神经元信息处理的核心特征，表明当大脑在两个大脑之间进行分工时，大脑具有深刻的适应性优势。侧化处理基于复杂的半球内和半球间机制，可以实现独立的半球特定编码，也可以交换、整合或抑制信息。合作或独立加工的潜在功能组织及其发展尚不清楚。因此，本项目提案的目的是了解两个专门的大脑半球如何沟通产生适应性决策和行为控制，以及发育过程中基因-环境相互作用如何塑造潜在的半球内和半球间过程。我们以鸽子的非对称组织视觉系统为模型，研究了环境因素光的影响，因为在胚胎发育过程中，视觉不对称的出现依赖于有偏见的视觉刺激。特别是在冲突情况下调查反应选择的任务（元控制）使我们能够探索半球内和半球间过程的相关性，从而促进半球特异性专门神经元回路的动态使用。我们想通过三组实验来比较有和没有胚胎光经验的鸽子的元控制模式来解决这个问题：实验一研究冲突选择中半球优势的出现在多大程度上取决于胚胎光刺激。实验二解决了刺激分析的偏侧模式在多大程度上依赖于个体发生光经验的问题，并探讨了与半球加工专门化相关的元控制的动态和灵活性。实验三旨在通过光遗传学手段揭示冲突决策中半球优势的神经元机制。我们的研究可以为个体发生的感觉体验如何影响两个大脑半球之间的有效互动提供重要的线索。这可能会极大地提高我们对侧化大脑的认知优势的理解，但也会对发育和精神疾病造成损害。

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.