Формирование изображения нарушителя в радиолучевых системах охраны

В статье рассмотрены вопросы улучшения информационных характеристик двухпозиционных радио- лучевых технических систем охраны. В качестве первого приближения сигналообразования использована лучевая модель формирования интерференционной картины ЭМ-волны. Разработан метод формирования двумерного изображения нарушителя в виде теневого силуэта. Получено обратное преобразование Кирхгофа, связывающее функцию пропускания объекта с распределением комплексной амплитуды ЭМ-волны в плоскости приема.У статті розглянуті питання поліпшення інформаційних характеристик двопозиційних радіопроменевих технічних систем охорони. Як перше наближення сигналостворення використана променева модель формування інтерференційної картини ЕМ-хвилі. Розроблено метод формування двовимірного зображення порушника у вигляді тіньового силуету. Отримано зворотне перетворення Кірхгофа, що зв’язує функцію пропускання об’єкта з розподілом комплексної амплітуди ЕМ-хвилі в площині прийому.The article deals with the issues of improving information characteristics of two-position radio-beam technical protection systems. The beam model of forming EM wav interference pattern is used as the first approximation of signal forming. The method of forming the intruder’s two-dimensional image as a shadow silhouette has been developed. The author has drawn the Kirchhoff inversion connecting the object’s transmission function with the distribution of the EM wave complex amplitude in the reception plane

Subdomain-mediated axon-axon signaling and chemoattraction cooperate to regulate afferent innervation of the lateral habenula

A dominant feature of neural circuitry is the organization of neuronal projections and synapses into specific brain nuclei or laminae. Lamina-specific connectivity is controlled by the selective expression of extracellular guidance and adhesion molecules in the target field. However, how (sub)nucleus-specific connections are established and whether axon-derived cues contribute to subdomain targeting are largely unknown. Here, we demonstrate that the lateral subnucleus of the habenula (lHb) determines its own afferent innervation by sending out efferent projections that express the cell adhesion molecule LAMP to reciprocally collect and guide dopaminergic afferents to the lHb-a phenomenon we term subdomain-mediated axon-axon signaling. This process of reciprocal axon-axon interactions cooperates with lHb-specific chemoattraction mediated by Netrin-1, which controls axon target entry, to ensure specific innervation of the lHb. We propose that cooperation between pretarget reciprocal axon-axon signaling and subdomain-restricted instructive cues provides a highly precise and general mechanism to establish subdomain-specific neural circuitry

Wiring up diversity: subset-specific development of midbrain dopaminergic neurons

The dopamine system of the ventral midbrain (mDA system) can be subdivided into three main nuclei: substantia nigra pars compacta (SNc, A9), ventral tegmental area (VTA, A10), and retrorubral field (RRF, A8). Dopaminergic neurons of the mDA system are characterized by the synthesis and release of the neurotransmitter dopamine, and the expression of tyrosine hydroxylase (TH) and the dopamine transporter (DAT). SNc mDA neurons contribute to the control of voluntary movement and their selective degeneration is a pathological hallmark of Parkinson’s disease. VTA mDA neurons play a role in positive and negative reinforcement, decision making, working memory, and aversion. Dopamine imbalance in VTA mDA neurons has been implicated in schizophrenia, attention deficit hyperactivity disorder (ADHD), obsessive-compulsive disorder (OCD), addiction, and depression. Their important physiological functions and implication in human disease has triggered an enormous interest in understanding the development and function of mDA neurons. It is becoming clear that neurons within the anatomically defined SNc and VTA nuclei are not homogeneous. Rather multiple distinct mDA neuron subsets exist within and across the boundaries of the SNc and VTA. For example, subsets that differ by specific molecular markers, by afferent inputs, and by the brain structures they innervate. To understand how these differences arise, the developmental origin and molecular programs in mDA neuron subsets are studied intensively. It is likely, and in part known, that different mDA neuron subsets express specific molecular cues that allow subset-specific differentiation, migration and axon guidance. This thesis aims at investigating the development of subsets of mDA neurons. New genetic tools to distinguish mDA neuron-clusters in vivo are generated and applied to understand the cellular and molecular mechanisms orchestrating the migration and axon guidance of mDA neuron subtypes

Neuronal subset-specific migration and axonal wiring mechanisms in the developing midbrain dopamine system

The midbrain dopamine (mDA) system is involved in the control of cognitive and motor behaviors, and is associated with several psychiatric and neurodegenerative diseases. mDA neurons receive diverse afferent inputs and establish efferent connections with many brain areas. Recent studies have unveiled a high level of molecular and cellular heterogeneity within the mDA system with specific subsets of mDA neurons displaying select molecular profiles and connectivity patterns. During mDA neuron development, molecular differences between mDA neuron subsets allow the establishment of subsetspecific afferent and efferent connections and functional roles. In this review, we summarize and discuss recent work defining novel mDA neuron subsets based on specific molecular signatures. Then, molecular cues are highlighted that control mDA neuron migration during embryonic development and that facilitate the formation of selective patterns of efferent connections. The review focuses largely on studies that show differences in these mechanisms between different subsets of mDA neurons and for which in vivo data is available, and is concluded by a section that discusses open questions and provides directions for further research

Remotely Produced and Axon-Derived Netrin-1 Instructs GABAergic Neuron Migration and Dopaminergic Substantia Nigra Development

et al.The midbrain dopamine (mDA) system is composed of molecularly and functionally distinct neuron subtypes that mediate specific behaviors and show select disease vulnerability, including in Parkinson’s disease. Despite progress in identifying mDA neuron subtypes, how these neuronal subsets develop and organize into functional brain structures remains poorly understood. Here we generate and use an intersectional genetic platform, Pitx3-ITC, to dissect the mechanisms of substantia nigra (SN) development and implicate the guidance molecule Netrin-1 in the migration and positioning of mDA neuron subtypes in the SN. Unexpectedly, we show that Netrin-1, produced in the forebrain and provided to the midbrain through axon projections, instructs the migration of GABAergic neurons into the ventral SN. This migration is required to confine mDA neurons to the dorsal SN. These data demonstrate that neuron migration can be controlled by remotely produced and axon-derived secreted guidance cues, a principle that is likely to apply more generally.This work was supported by mDANeurodev, FP/2007–2011 grant 222999; Universiteit Utrecht (MIND, Dynamics of Youth); The People Program (Marie Curie Actions) of the European Union’s Seventh Framework Program (FP7) 2007–2013 under REA grant 289581 (NPlast); the Netherlands Organization for Scientific Research (ALW-NWO VICI); and Stichting Parkinson Fonds to R.J.P. A.C. and J.A.M.-B. were supported by the Programme Investissements d’Avenir IHU FOReSIGHT (ANR-18-IAHU-01).Peer reviewe

Subdomain--Mediated Axon--Axon Signalingand Chemoattraction Cooperate to RegulateAfferent Innervation of the Lateral Habenula

SUMMARY A dominant feature of neural circuitry is the organization of neuronal projections and synapses into specific brain nuclei or laminae. Lamina-specific connectivity is controlled by the selective expression of extracellular guidance and adhesion molecules in the target field. However, how (sub)nucleusspecific connections are established and whether axonderived cues contribute to subdomain targeting are largely unknown. Here, we demonstrate that the lateral subnucleus of the habenula (lHb) determines its own afferent innervation by sending out efferent projections that express the cell adhesion molecule LAMP to reciprocally collect and guide dopaminergic afferents to the lHb-a phenomenon we term subdomain-mediated axon-axon signaling. This process of reciprocal axon-axon interactions cooperates with lHb-specific chemoattraction mediated by Netrin-1, which controls axon target entry, to ensure specific innervation of the lHb. We propose that cooperation between pretarget reciprocal axon-axon signaling and subdomain-restricted instructive cues provides a highly precise and general mechanism to establish subdomain-specific neural circuitry. INTRODUCTION The formation of precise connections between afferent axons and their partner neurons is essential for the assembly of functional neural circuits. The organization of the nervous system in two main anatomical units, i.e., brain nuclei and laminated structures, facilitates this process by spatially grouping synaptic partners and enabling subdomain-restricted expression of instructive cues. Despite the important role of these organizing principles, our understanding of the cellular and molecular basis of laminaor subnucleus-specific circuit development is still limited. Our current knowledge of subdomain-specific axon targeting mainly derives from work on laminated structures, and recent studies have uncovered different molecular strategies that control lamina-specific targeting independent of neural activity. This work shows that initially target-derived, membrane-associated, or secreted guidance cues function to direct axon projections to or exclude them from specific layers. Subsequently, combinatorial expression of cell adhesion molecules facilitates the formation of contacts between matched pre-and postsynaptic neuron