Volume 27, Issue 4

The neural mechanisms that balance waking and sleep to ensure adequate sleep quality in mammals are highly complex, often eluding functional insight. In the last two decades, researchers made impressive progress in studying the less complex brain of the invertebrate model organism Drosophila melanogaster , which has led to a deeper understanding of the neural principles of sleep regulation. Here, we will review these findings to illustrate that neural networks require sleep to undergo synaptic reorganization that allows for the incorporation of experiences made during the waking hours. Sleep need, therefore, can arise as a consequence of sensory processing, often signalized by neural networks as they synchronize their electrical patterns to generate slow-wave activity. The slow-wave activity provides the neurophysiological basis to establish a sensory gate that suppresses sensory processing to provide a resting phase which promotes synaptic rescaling and clearance of metabolites from the brain. Moreover, we demonstrate how neural networks for homeostatic and circadian sleep regulation interact to consolidate sleep into a specific daily period. We particularly highlight that the basic functions and physiological principles of sleep are highly conserved throughout the phylogenetic spectrum, allowing us to identify the functional components and neural interactions that construct the neural architecture of sleep regulation.

Exposure to environmental pollutants like chemicals or air pollution is major health concern for the human population. Especially the nervous system is a sensitive target for environmental toxins with exposures leading to life stage-dependent neurotoxicity. Developmental and adult neurotoxicity are characterized by specific adverse outcomes ranging from neurodevelopmental disorders to neurodegenerative diseases like Alzheimer’s and Parkinson’s disease. The risk assessment process for human health protection is currently undergoing a paradigm change toward new approach methods that allow mechanism-based toxicity assessment. As a flagship project, an in vitro battery of test methods for developmental neurotoxicity evaluation is currently supported by the Organization for Economic Co-operation and Development (OECD). A plethora of stem cell-based methods including brain spheres and organoids are currently further developed to achieve time- and cost-saving tools for linking MoA-based hazards to adverse health effects observed in humans.

Neuroscientific discoveries and the development of recording and stimulation tools are deeply connected. Over the past decades, the progress in seamlessly integrating such tools in the form of neuroelectronic devices has been tremendous. Here, we review recent advances and key aspects of this goal. Firstly, we illustrate improvements with respect to the coupling between cells/tissue and recording/stimulation electrodes. Thereafter, we cover attempts to mitigate the foreign body response by reducing the devices’ invasiveness. We follow up with a description of specialized electronic hardware aimed at the needs of bioelectronic applications. Lastly, we outline how additional modalities such as optical techniques or ultrasound could in the future be integrated into neuroelectronic implants. Zusammenfassung Neurowissenschaftliche Entdeckungen und die Entwicklung von Ableitungs- und Stimulationsmethoden sind stark verknüpft. Im Laufe der letzten Jahrzehnte hat sich ein immenser Fortschritt im Hinblick auf die nahtlose Integration solcher Methoden in Form von neuroelektronischen Schnittstellen ergeben. In diesem Artikel geben wir einen Überblick über aktuelle Entwicklungen in diesem Feld. Wir beleuchten zuerst Verbesserungen der Kopplung zwischen Zellen/Gewebe und Ableitungs- bzw. Stimulationselektroden. Danach betrachten wir Ansätze zur Vermeidung von Fremdkörperreaktionen durch eine reduzierte Invasivität der Schnittstellen. Anschließend beschreiben wir spezialisierte elektronische Hardware für bioelektronische Anwendungen. Zuletzt zeigen wir auf, wie neue Modalitäten z.B. durch optische Techniken oder Ultraschall zukünftig in neuroelektronische Implantate integriert werden könnten.

The nervous system with its complex organizational features and functions is well-known for its impressive ability to process information and drive countless biological processes. It has come to the surprise of many that the nervous system can also be intimately involved in an unwelcome area of human life: the initiation and progression of cancer. For brain tumors, the parallels to neurodevelopment and nervous system function can be found on multiple levels. First, cancer cells of incurable gliomas interconnect with long cellular extensions to a large communicating multicellular network. Second, indirect and direct neuronal input can generate, activate, and control brain tumor growth. Third, it is becoming increasingly clear that those features not only drive brain tumor progression but also the notorious resistance of these tumors against standard antitumor therapies. Remarkably, these recent insights have already generated novel ideas for better antitumor therapies.