Cross-modality mapping using image varifolds to align tissue-scale atlases to molecular-scale measures with application to 2D brain sections

This paper explicates a solution to building correspondences between molecular-scale transcriptomics and tissue-scale atlases. This problem arises in atlas construction and cross-specimen/technology alignment where specimens per emerging technology remain sparse and conventional image representations cannot efficiently model the high dimensions from subcellular detection of thousands of genes. We address these challenges by representing spatial transcriptomics data as generalized functions encoding position and high-dimensional feature (gene, cell type) identity. We map onto low-dimensional atlas ontologies by modeling regions as homogeneous random fields with unknown transcriptomic feature distribution. We solve simultaneously for the minimizing geodesic diffeomorphism of coordinates through LDDMM and for these latent feature densities. We map tissue-scale mouse brain atlases to gene-based and cell-based transcriptomics data from MERFISH and BARseq technologies and to histopathology and cross-species atlases to illustrate integration of diverse molecular and cellular datasets into a single coordinate system as a means of comparison and further atlas construction.

A transcriptomic taxonomy of mouse brain-wide spinal projecting neurons

The brain controls nearly all bodily functions via spinal projecting neurons (SPNs) that carry command signals from the brain to the spinal cord. However, a comprehensive molecular characterization of brain-wide SPNs is still lacking. Here we transcriptionally profiled a total of 65,002 SPNs, identified 76 region-specific SPN types, and mapped these types into a companion atlas of the whole mouse brain1. This taxonomy reveals a three-component organization of SPNs: (1) molecularly homogeneous excitatory SPNs from the cortex, red nucleus and cerebellum with somatotopic spinal terminations suitable for point-to-point communication; (2) heterogeneous populations in the reticular formation with broad spinal termination patterns, suitable for relaying commands related to the activities of the entire spinal cord; and (3) modulatory neurons expressing slow-acting neurotransmitters and/or neuropeptides in the hypothalamus, midbrain and reticular formation for 'gain setting' of brain-spinal signals. In addition, this atlas revealed a LIM homeobox transcription factor code that parcellates the reticulospinal neurons into five molecularly distinct and spatially segregated populations. Finally, we found transcriptional signatures of a subset of SPNs with large soma size and correlated these with fast-firing electrophysiological properties. Together, this study establishes a comprehensive taxonomy of brain-wide SPNs and provides insight into the functional organization of SPNs in mediating brain control of bodily functions.

A high-resolution transcriptomic and spatial atlas of cell types in the whole mouse brain

The mammalian brain consists of millions to billions of cells that are organized into many cell types with specific spatial distribution patterns and structural and functional properties1-3. Here we report a comprehensive and high-resolution transcriptomic and spatial cell-type atlas for the whole adult mouse brain. The cell-type atlas was created by combining a single-cell RNA-sequencing (scRNA-seq) dataset of around 7 million cells profiled (approximately 4.0 million cells passing quality control), and a spatial transcriptomic dataset of approximately 4.3 million cells using multiplexed error-robust fluorescence in situ hybridization (MERFISH). The atlas is hierarchically organized into 4 nested levels of classification: 34 classes, 338 subclasses, 1,201 supertypes and 5,322 clusters. We present an online platform, Allen Brain Cell Atlas, to visualize the mouse whole-brain cell-type atlas along with the single-cell RNA-sequencing and MERFISH datasets. We systematically analysed the neuronal and non-neuronal cell types across the brain and identified a high degree of correspondence between transcriptomic identity and spatial specificity for each cell type. The results reveal unique features of cell-type organization in different brain regions-in particular, a dichotomy between the dorsal and ventral parts of the brain. The dorsal part contains relatively fewer yet highly divergent neuronal types, whereas the ventral part contains more numerous neuronal types that are more closely related to each other. Our study also uncovered extraordinary diversity and heterogeneity in neurotransmitter and neuropeptide expression and co-expression patterns in different cell types. Finally, we found that transcription factors are major determinants of cell-type classification and identified a combinatorial transcription factor code that defines cell types across all parts of the brain. The whole mouse brain transcriptomic and spatial cell-type atlas establishes a benchmark reference atlas and a foundational resource for integrative investigations of cellular and circuit function, development and evolution of the mammalian brain.

Transcriptomic cytoarchitecture reveals principles of human neocortex organization

Variation in cytoarchitecture is the basis for the histological definition of cortical areas. We used single cell transcriptomics and performed cellular characterization of the human cortex to better understand cortical areal specialization. Single-nucleus RNA-sequencing of 8 areas spanning cortical structural variation showed a highly consistent cellular makeup for 24 cell subclasses. However, proportions of excitatory neuron subclasses varied substantially, likely reflecting differences in connectivity across primary sensorimotor and association cortices. Laminar organization of astrocytes and oligodendrocytes also differed across areas. Primary visual cortex showed characteristic organization with major changes in the excitatory to inhibitory neuron ratio, expansion of layer 4 excitatory neurons, and specialized inhibitory neurons. These results lay the groundwork for a refined cellular and molecular characterization of human cortical cytoarchitecture and areal specialization.

Morphoelectric and transcriptomic divergence of the layer 1 interneuron repertoire in human versus mouse neocortex

Neocortical layer 1 (L1) is a site of convergence between pyramidal-neuron dendrites and feedback axons where local inhibitory signaling can profoundly shape cortical processing. Evolutionary expansion of human neocortex is marked by distinctive pyramidal neurons with extensive L1 branching, but whether L1 interneurons are similarly diverse is underexplored. Using Patch-seq recordings from human neurosurgical tissue, we identified four transcriptomic subclasses with mouse L1 homologs, along with distinct subtypes and types unmatched in mouse L1. Subclass and subtype comparisons showed stronger transcriptomic differences in human L1 and were correlated with strong morphoelectric variability along dimensions distinct from mouse L1 variability. Accompanied by greater layer thickness and other cytoarchitecture changes, these findings suggest that L1 has diverged in evolution, reflecting the demands of regulating the expanded human neocortical circuit.

Signature morphoelectric properties of diverse GABAergic interneurons in the human neocortex

Human cortex transcriptomic studies have revealed a hierarchical organization of γ-aminobutyric acid-producing (GABAergic) neurons from subclasses to a high diversity of more granular types. Rapid GABAergic neuron viral genetic labeling plus Patch-seq (patch-clamp electrophysiology plus single-cell RNA sequencing) sampling in human brain slices was used to reliably target and analyze GABAergic neuron subclasses and individual transcriptomic types. This characterization elucidated transitions between PVALB and SST subclasses, revealed morphological heterogeneity within an abundant transcriptomic type, identified multiple spatially distinct types of the primate-specialized double bouquet cells (DBCs), and shed light on cellular differences between homologous mouse and human neocortical GABAergic neuron types. These results highlight the importance of multimodal phenotypic characterization for refinement of emerging transcriptomic cell type taxonomies and for understanding conserved and specialized cellular properties of human brain cell types.

Enhancer-AAVs allow genetic access to oligodendrocytes and diverse populations of astrocytes across species

Proper brain function requires the assembly and function of diverse populations of neurons and glia. Single cell gene expression studies have mostly focused on characterization of neuronal cell diversity; however, recent studies have revealed substantial diversity of glial cells, particularly astrocytes. To better understand glial cell types and their roles in neurobiology, we built a new suite of adeno-associated viral (AAV)-based genetic tools to enable genetic access to astrocytes and oligodendrocytes. These oligodendrocyte and astrocyte enhancer-AAVs are highly specific (usually > 95% cell type specificity) with variable expression levels, and our astrocyte enhancer-AAVs show multiple distinct expression patterns reflecting the spatial distribution of astrocyte cell types. To provide the best glial-specific functional tools, several enhancer-AAVs were: optimized for higher expression levels, shown to be functional and specific in rat and macaque, shown to maintain specific activity in epilepsy where traditional promoters changed activity, and used to drive functional transgenes in astrocytes including Cre recombinase and acetylcholine-responsive sensor iAChSnFR. The astrocyte-specific iAChSnFR revealed a clear reward-dependent acetylcholine response in astrocytes of the nucleus accumbens during reinforcement learning. Together, this collection of glial enhancer-AAVs will enable characterization of astrocyte and oligodendrocyte populations and their roles across species, disease states, and behavioral epochs.

Integrated multimodal cell atlas of Alzheimer's disease

Alzheimer's disease (AD) is the most common cause of dementia in older adults. Neuropathological and imaging studies have demonstrated a progressive and stereotyped accumulation of protein aggregates, but the underlying molecular and cellular mechanisms driving AD progression and vulnerable cell populations affected by disease remain coarsely understood. The current study harnesses single cell and spatial genomics tools and knowledge from the BRAIN Initiative Cell Census Network to understand the impact of disease progression on middle temporal gyrus cell types. We used image-based quantitative neuropathology to place 84 donors spanning the spectrum of AD pathology along a continuous disease pseudoprogression score and multiomic technologies to profile single nuclei from each donor, mapping their transcriptomes, epigenomes, and spatial coordinates to a common cell type reference with unprecedented resolution. Temporal analysis of cell-type proportions indicated an early reduction of Somatostatin-expressing neuronal subtypes and a late decrease of supragranular intratelencephalic-projecting excitatory and Parvalbumin-expressing neurons, with increases in disease-associated microglial and astrocytic states. We found complex gene expression differences, ranging from global to cell type-specific effects. These effects showed different temporal patterns indicating diverse cellular perturbations as a function of disease progression. A subset of donors showed a particularly severe cellular and molecular phenotype, which correlated with steeper cognitive decline. We have created a freely available public resource to explore these data and to accelerate progress in AD research at SEA-AD.org.

A Universal Method for Crossing Molecular and Atlas Modalities using Simplex-Based Image Varifolds and Quadratic Programming

This paper explicates a solution to the problem of building correspondences between molecular-scale transcriptomics and tissue-scale atlases. The central model represents spatial transcriptomics as generalized functions encoding molecular position and high-dimensional transcriptomic-based (gene, cell type) identity. We map onto low-dimensional atlas ontologies by modeling each atlas compartment as a homogeneous random field with unknown transcriptomic feature distribution. The algorithm presented solves simultaneously for the minimizing geodesic diffeomorphism of coordinates and latent atlas transcriptomic feature fractions by alternating LDDMM optimization for coordinate transformations and quadratic programming for the latent transcriptomic variables. We demonstrate the universality of the algorithm in mapping tissue atlases to gene-based and cell-based MERFISH datasets as well as to other tissue scale atlases. The joint estimation of diffeomorphisms and latent feature distributions allows integration of diverse molecular and cellular datasets into a single coordinate system and creates an avenue of comparison amongst atlas ontologies for continued future development.

A high-resolution transcriptomic and spatial atlas of cell types in the whole mouse brain

The mammalian brain is composed of millions to billions of cells that are organized into numerous cell types with specific spatial distribution patterns and structural and functional properties. An essential step towards understanding brain function is to obtain a parts list, i.e., a catalog of cell types, of the brain. Here, we report a comprehensive and high-resolution transcriptomic and spatial cell type atlas for the whole adult mouse brain. The cell type atlas was created based on the combination of two single-cell-level, whole-brain-scale datasets: a single-cell RNA-sequencing (scRNA-seq) dataset of ~7 million cells profiled, and a spatially resolved transcriptomic dataset of ~4.3 million cells using MERFISH. The atlas is hierarchically organized into five nested levels of classification: 7 divisions, 32 classes, 306 subclasses, 1,045 supertypes and 5,200 clusters. We systematically analyzed the neuronal, non-neuronal, and immature neuronal cell types across the brain and identified a high degree of correspondence between transcriptomic identity and spatial specificity for each cell type. The results reveal unique features of cell type organization in different brain regions, in particular, a dichotomy between the dorsal and ventral parts of the brain: the dorsal part contains relatively fewer yet highly divergent neuronal types, whereas the ventral part contains more numerous neuronal types that are more closely related to each other. We also systematically characterized cell-type specific expression of neurotransmitters, neuropeptides, and transcription factors. The study uncovered extraordinary diversity and heterogeneity in neurotransmitter and neuropeptide expression and co-expression patterns in different cell types across the brain, suggesting they mediate a myriad of modes of intercellular communications. Finally, we found that transcription factors are major determinants of cell type classification in the adult mouse brain and identified a combinatorial transcription factor code that defines cell types across all parts of the brain. The whole-mouse-brain transcriptomic and spatial cell type atlas establishes a benchmark reference atlas and a foundational resource for deep and integrative investigations of cell type and circuit function, development, and evolution of the mammalian brain.

A single-cell resolution gene expression atlas of the larval zebrafish brain

The advent of multimodal brain atlases promises to accelerate progress in neuroscience by allowing in silico queries of neuron morphology, connectivity, and gene expression. We used multiplexed fluorescent in situ RNA hybridization chain reaction (HCR) technology to generate expression maps across the larval zebrafish brain for a growing set of marker genes. The data were registered to the Max Planck Zebrafish Brain (mapzebrain) atlas, thus allowing covisualization of gene expression, single-neuron tracings, and expertly curated anatomical segmentations. Using post hoc HCR labeling of the immediate early gene cfos, we mapped responses to prey stimuli and food ingestion across the brain of freely swimming larvae. This unbiased approach revealed, in addition to previously described visual and motor areas, a cluster of neurons in the secondary gustatory nucleus, which express the marker calb2a, as well as a specific neuropeptide Y receptor, and project to the hypothalamus. This discovery exemplifies the power of this new atlas resource for zebrafish neurobiology.

Neural assemblies uncovered by generative modeling explain whole-brain activity statistics and reflect structural connectivity

Patterns of endogenous activity in the brain reflect a stochastic exploration of the neuronal state space that is constrained by the underlying assembly organization of neurons. Yet, it remains to be shown that this interplay between neurons and their assembly dynamics indeed suffices to generate whole-brain data statistics. Here, we recorded the activity from ∼40,000 neurons simultaneously in zebrafish larvae, and show that a data-driven generative model of neuron-assembly interactions can accurately reproduce the mean activity and pairwise correlation statistics of their spontaneous activity. This model, the compositional Restricted Boltzmann Machine (cRBM), unveils ∼200 neural assemblies, which compose neurophysiological circuits and whose various combinations form successive brain states. We then performed in silico perturbation experiments to determine the interregional functional connectivity, which is conserved across individual animals and correlates well with structural connectivity. Our results showcase how cRBMs can capture the coarse-grained organization of the zebrafish brain. Notably, this generative model can readily be deployed to parse neural data obtained by other large-scale recording techniques.

The mediating role of state anger in the associations between intentions to participate in the criminal trial and psychopathology in traumatically bereaved people

Victims of crimes have been granted increasing procedural rights to participate in the juridical process since the mid 1990s. However, knowledge about the (anti)-therapeutic effect of participation is limited. We examined the associations between symptom levels of persistent complex bereavement disorder (PCBD), posttraumatic stress disorder (PTSD), and depression and the intention to participate in a criminal trial. Furthermore, we investigated the mediating role of state anger in these associations. People who lost loved ones after a plane disaster with flight MH17 (N = 203) completed questionnaires within three weeks before the start of the criminal trial. Mediation analyses indicated that people, who did not intend to actively participate in the trial by delivering a written or oral victim statement, were less likely to experience anger, which is, in turn, associated with attenuated psychopathology levels. State anger explains 68% of the effect of the intention to exercise the right to speak on PCBD levels. An important limitation is the cross-sectional study design, which precludes conclusions about temporal associations. More research is needed to improve preparation and support of bereaved people when they intend to exercise their victim rights during a criminal trial.

CT Cervical Spine Fracture Detection Using a Convolutional Neural Network

BACKGROUND AND PURPOSE

Multidetector CT has emerged as the standard of care imaging technique to evaluate cervical spine trauma. Our aim was to evaluate the performance of a convolutional neural network in the detection of cervical spine fractures on CT.

MATERIALS AND METHODS

We evaluated C-spine, an FDA-approved convolutional neural network developed by Aidoc to detect cervical spine fractures on CT. A total of 665 examinations were included in our analysis. Ground truth was established by retrospective visualization of a fracture on CT by using all available CT, MR imaging, and convolutional neural network output information. The ĸ coefficients, sensitivity, specificity, and positive and negative predictive values were calculated with 95% CIs comparing diagnostic accuracy and agreement of the convolutional neural network and radiologist ratings, respectively, compared with ground truth.

RESULTS

Convolutional neural network accuracy in cervical spine fracture detection was 92% (95% CI, 90%-94%), with 76% (95% CI, 68%-83%) sensitivity and 97% (95% CI, 95%-98%) specificity. The radiologist accuracy was 95% (95% CI, 94%-97%), with 93% (95% CI, 88%-97%) sensitivity and 96% (95% CI, 94%-98%) specificity. Fractures missed by the convolutional neural network and by radiologists were similar by level and location and included fractured anterior osteophytes, transverse processes, and spinous processes, as well as lower cervical spine fractures that are often obscured by CT beam attenuation.

CONCLUSIONS

The convolutional neural network holds promise at both worklist prioritization and assisting radiologists in cervical spine fracture detection on CT. Understanding the strengths and weaknesses of the convolutional neural network is essential before its successful incorporation into clinical practice. Further refinements in sensitivity will improve convolutional neural network diagnostic utility.

Massive migration from the steppe was a source for Indo-European languages in Europe

We generated genome-wide data from 69 Europeans who lived between 8,000-3,000 years ago by enriching ancient DNA libraries for a target set of almost 400,000 polymorphisms. Enrichment of these positions decreases the sequencing required for genome-wide ancient DNA analysis by a median of around 250-fold, allowing us to study an order of magnitude more individuals than previous studies and to obtain new insights about the past. We show that the populations of Western and Far Eastern Europe followed opposite trajectories between 8,000-5,000 years ago. At the beginning of the Neolithic period in Europe, ∼8,000-7,000 years ago, closely related groups of early farmers appeared in Germany, Hungary and Spain, different from indigenous hunter-gatherers, whereas Russia was inhabited by a distinctive population of hunter-gatherers with high affinity to a ∼24,000-year-old Siberian. By ∼6,000-5,000 years ago, farmers throughout much of Europe had more hunter-gatherer ancestry than their predecessors, but in Russia, the Yamnaya steppe herders of this time were descended not only from the preceding eastern European hunter-gatherers, but also from a population of Near Eastern ancestry. Western and Eastern Europe came into contact ∼4,500 years ago, as the Late Neolithic Corded Ware people from Germany traced ∼75% of their ancestry to the Yamnaya, documenting a massive migration into the heartland of Europe from its eastern periphery. This steppe ancestry persisted in all sampled central Europeans until at least ∼3,000 years ago, and is ubiquitous in present-day Europeans. These results provide support for a steppe origin of at least some of the Indo-European languages of Europe.

Rhythmic control of activity and sleep by class B1 GPCRs

Members of the class B1 family of G-protein coupled receptors (GPCRs) whose ligands are neuropeptides have been implicated in regulation of circadian rhythms and sleep in diverse metazoan clades. This review discusses the cellular and molecular mechanisms by which class B1 GPCRs, especially the mammalian VPAC2 receptor and its functional homologue PDFR in Drosophila and C. elegans, regulate arousal and daily rhythms of sleep and wake. There are remarkable parallels in the cellular and molecular roles played by class B1 intercellular signaling pathways in coordinating arousal and circadian timekeeping across multiple cells and tissues in these very different genetic model organisms.

Calcitonin gene-related peptide neurons mediate sleep-specific circadian output in Drosophila

BACKGROUND

Imbalances in amount and timing of sleep are harmful to physical and mental health. Therefore, the study of the underlying mechanisms is of great biological importance. Proper timing and amount of sleep are regulated by both the circadian clock and homeostatic sleep drive. However, very little is known about the cellular and molecular mechanisms by which the circadian clock regulates sleep. In this study, we describe a novel role for diuretic hormone 31 (DH31), the fly homolog of the vertebrate neuropeptide calcitonin gene-related peptide, as a circadian wake-promoting signal that awakens the fly in anticipation of dawn.

RESULTS

Analysis of loss-of-function and gain-of-function Drosophila mutants demonstrates that DH31 suppresses sleep late at night. DH31 is expressed by a subset of dorsal circadian clock neurons that also express the receptor for the circadian neuropeptide pigment-dispersing factor (PDF). PDF secreted by the ventral pacemaker subset of circadian clock neurons acts on PDF receptors in the DH31-expressing dorsal clock neurons to increase DH31 secretion before dawn. Activation of PDF receptors in DH31-positive DN1 specifically affects sleep and has no effect on circadian rhythms, thus constituting a dedicated locus for circadian regulation of sleep.

CONCLUSIONS

We identified a novel signaling molecule (DH31) as part of a neuropeptide relay mechanism for circadian control of sleep. Our results indicate that outputs of the clock controlling sleep and locomotor rhythms are mediated via distinct neuronal pathways.

Self-Association of Cholesterol in Carbon Tetrachloride

Analysis of infrared hydroxyl multimer absorbances of dilute solutions of cholesterol in carbon tetrachloride as a function of the monomer absorbance strongly favours the interpretation of the association of this alcohol with a monomer-dimer-tetramer model up to a molar fraction of 0.012. This model also explains very well the concentration dependence of the apparent dipole moment. Equilibrium constants and dielectric parameters have been determined. Suggestions about the structure of the various associates are made.

Comparison between transient and frequency modulated excitation: application to silicon nitride and aluminum oxide coatings of silicon

Contactless measurements of the lifetime of charge carriers are presented with varying ways of photo excitation: with and without bias light and pulsed and frequency modulated. These methods are applied to the study of the surface passivation of single crystalline silicon by a-SiN(x):H and Al2O3 coatings. The properties of these coatings are investigated under consideration of the merits of the different methods.

Genetically targeted optical electrophysiology in intact neural circuits

Nervous systems process information by integrating the electrical activity of neurons in complex networks. This motivates the long-standing interest in using optical methods to simultaneously monitor the membrane potential of multiple genetically targeted neurons via expression of genetically encoded fluorescent voltage indicators (GEVIs) in intact neural circuits. No currently available GEVIs have demonstrated robust signals in intact brain tissue that enable reliable recording of individual electrical events simultaneously in multiple neurons. Here, we show that the recently developed "ArcLight" GEVI robustly reports both subthreshold events and action potentials in genetically targeted neurons in the intact Drosophila fruit fly brain and reveals electrical signals in neurite branches. In the same way that genetically encoded fluorescent sensors have revolutionized the study of intracellular Ca(2+) signals, ArcLight now enables optical measurement in intact neural circuits of membrane potential, the key cellular parameter that underlies neuronal information processing.

Reproduction-related sound production of grasshoppers regulated by internal state and actual sensory environment

The interplay of neural and hormonal mechanisms activated by entero- and extero-receptors biases the selection of actions by decision making neuronal circuits. The reproductive behavior of acoustically communicating grasshoppers, which is regulated by short-term neural and longer-term hormonal mechanisms, has frequently been used to study the cellular and physiological processes that select particular actions from the species-specific repertoire of behaviors. Various grasshoppers communicate with species- and situation-specific songs in order to attract and court mating partners, to signal reproductive readiness, or to fend off competitors. Selection and coordination of type, intensity, and timing of sound signals is mediated by the central complex, a highly structured brain neuropil known to integrate multimodal pre-processed sensory information by a large number of chemical messengers. In addition, reproductive activity including sound production critically depends on maturation, previous mating experience, and oviposition cycles. In this regard, juvenile hormone released from the corpora allata has been identified as a decisive hormonal signal necessary to establish reproductive motivation in grasshopper females. Both regulatory systems, the central complex mediating short-term regulation and the corpora allata mediating longer-term regulation of reproduction-related sound production mutually influence each other’s activity in order to generate a coherent state of excitation that promotes or suppresses reproductive behavior in respective appropriate or inappropriate situations. This review summarizes our current knowledge about extrinsic and intrinsic factors that influence grasshopper reproductive motivation, their representation in the nervous system and their integrative processing that mediates the initiation or suppression of reproductive behaviors.

Suppression of grasshopper sound production by nitric oxide-releasing neurons of the central complex

The central complex of acridid grasshoppers integrates sensory information pertinent to reproduction-related acoustic communication. Activation of nitric oxide (NO)/cyclic GMP-signaling by injection of NO donors into the central complex of restrained Chorthippus biguttulus females suppresses muscarine-stimulated sound production. In contrast, sound production is released by aminoguanidine (AG)-mediated inhibition of nitric oxide synthase (NOS) in the central body, suggesting a basal release of NO that suppresses singing in this situation. Using anti-citrulline immunocytochemistry to detect recent NO production, subtypes of columnar neurons with somata located in the pars intercerebralis and tangential neurons with somata in the ventro-median protocerebrum were distinctly labeled. Their arborizations in the central body upper division overlap with expression patterns for NOS and with the site of injection where NO donors suppress sound production. Systemic application of AG increases the responsiveness of unrestrained females to male calling songs. Identical treatment with the NOS inhibitor that increased male song-stimulated sound production in females induced a marked reduction of citrulline accumulation in central complex columnar and tangential neurons. We conclude that behavioral situations that are unfavorable for sound production (like being restrained) activate NOS-expressing central body neurons to release NO and elevate the behavioral threshold for sound production in female grasshoppers.

Muscarinic excitation in grasshopper song control circuits is limited by acetylcholinesterase activity

The species- and situation-specific sound production of grasshoppers can be stimulated by focal application of both nicotinic and muscarinic receptor agonists into the central body complex of the protocerebrum. Pressure injection of the intrinsic transmitter acetylcholine only elicits fast and short-lived responses related to nicotinic receptor-mediated excitation. Prolonged sound production that includes complex song patterns requires muscarinic receptor-mediated excitation. In addition, basal muscarinic excitation in the central body neuropil seems to determine the general motivation of a grasshopper to stridulate. To demonstrate that endogenous acetylcholinesterase limits the activation of muscarinic receptors by synaptically released acetylcholine in the central body of Chorthippus biguttulus, we investigated both its presence in the brain and effects on sound production resulting from inhibition of esterase activity. Acetylcholinesterase activity was detected in the upper and lower division of the central body. Both these neuropils known to be involved in the cephalic control of stridulation were also shown to contain muscarinic acetylcholine receptors expressed by columnar neurons suggested to serve as output neurons of the central complex. Pressure injection of the acetylcholinesterase inhibitor eserine into protocerebral control circuits of restrained male grasshoppers stimulated long-lasting stridulation that depended on scopolamine-sensitive muscarinic receptors. In restrained males, eserine released the typical response song by potentiating the stimulatory effect of the conspecific female song. Eserine-mediated inhibition of acetylcholinesterase in the central body prolongs the presence of synaptically released acetylcholine at its postsynaptic receptors and increases its potency to activate muscarinic receptor-initiated signaling pathways acting to promote grasshopper sound production.

Results of G004, a phase IIb actively controlled clinical trial with the TGF-b2 targeted compound AP 12009 for recurrent anaplastic astrocytoma

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Background: In 3 phase I/II dose-escalation studies the TGF-β2 specific compound AP 12009 proved to be well tolerated and revealed an excellent safety profile. Furthermore, antitumor activity including complete tumor remissions was observed. Methods: G004 is an international open-label, actively controlled, dose finding phase IIb trial in adult patients with histopathologically confirmed recurrent high-grade glioma. 145 patients with recurrent anaplastic astrocytoma (AA, WHO grade III) or glioblastoma (GBM, WHO grade IV) were enrolled into the study. Objective of the current phase IIb study is to compare the efficacy and safety of two doses of AP 12009 and standard treatment. Patients were randomized to receive either one of two doses of AP 12009 (10 μM or 80 μM) or standard chemotherapy (TMZ or PCV). AP 12009 was administered intratumorally by CED. 134 patients received treatment and all of them have completed active treatment. Primary endpoint is tumor response by local and central MRI reading and survival. Results: Here we report on patients with recurrent AA (for GBM see separate Abstract). 38 patients with AA (68% male, 32% female; median age 39, range 22–60; median Karnofsky performance status: 90, range 70–100) were treated. 26 patients received AP 12009 (10 μM or 80 μM), 12 patients were treated with TMZ or PCV. Up to now, in 89 patients treated with AP 12009 (both AA and GBM patients) 6 SAEs possibly related to the study drug and 37 procedure related SAEs (92% mild or moderate) were documented. Partial and complete tumor responses were observed. Exact response rates will be determined after central MRI reading is completed. Responses in the AP 12009 groups are long lasting. The results confirm the good safety profile of AP 12009 as well as the efficacy data seen in phase I studies. The median overall survival is not yet reached. Conclusions: The long-term tumor free survival of several patients may actually hint towards a potential to cure some patients with this devastating disease. Phase III clinical trials in both AA and GBM patients are currently in preparation.

[Table: see text]

Results of G004, a phase IIb study in recurrent glioblastoma patients with the TGF-b2 targeted compound AP 12009

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Background: In high-grade glioma (HGG), TGF-β2 expression strongly correlates with tumor grade and is highly predictive of disease outcome. The compound AP 12009 inhibits TGF-β2 expression. Preclinical results revealed strong multimodal activity including reversal of TGF-β induced immunosuppression, inhibition of tumor cell migration and proliferation. In 3 preceding phase I/II dose escalation studies, 24 HGG patients had been treated with AP 12009. Methods: G004 is an international open-label, actively controlled, dose finding phase IIb study. Objective is a comparison of two doses of AP 12009 and standard chemotherapy for efficacy and safety. 145 patients with histopathologically confirmed recurrent anaplastic astrocytoma (AA, WHO grade III) or glioblastoma (GBM, WHO grade IV) were randomized into one of 3 treatment arms. 134 patients received treatment AP 12009 10μM, AP 12009 80μM or standard chemotherapy (TMZ or PCV). AP 12009 was applied locoregionally by convection-enhanced delivery during a 6-month active treatment period with 7-day-on, 7-day-off cycles. Primary endpoint is tumor response by local and central MRI reading. All patients have completed active treatment. Follow-up for survival and tumor response assessed by local and central MRI reading is ongoing. Results: Here we report on patients with recurrent GBM (AA see separate Abstract). 96 GBM patients (37% female, 63% male; median age 51 years, range 20–74; median Karnofsky performance status 90, range 70–100) have been treated. 63 GBM patients received AP 12009 (28 pt. 10 μM, 35 pt. 80 μM), 33 patients received standard chemotherapy. Data were evaluated by an independent Data and Safety Monitoring Board. Up to now, in 89 patients treated with AP 12009 (AA and GBM patients) 6 SAEs possibly related to the study drug and 37 procedure related SAEs (92% mild or moderate) were documented. Several long-term tumor responses were observed by local MRI reading. Exact response rates are being determined by central reading. Conclusions: Responses in patients treated with AP 12009 in both AA and GBM patients are long lasting with a good quality of life. Phase III clinical trials in AA and GBM patients are currently in preparation.

[Table: see text]

Nitric oxide/cyclic guanosine monophosphate signaling in the central complex of the grasshopper brain inhibits singing behavior

Grasshopper sound production, in the context of mate finding, courtship, and rivalry, is controlled by the central body complex in the protocerebrum. Stimulation of muscarinic acetylcholine receptors in the central complex has been demonstrated to stimulate specific singing in various grasshoppers including the species Chorthippus biguttulus. Sound production elicited by stimulation of muscarinic acetylcholine receptors in the central complex is inhibited by co-applications of various drugs activating the nitric oxide/cyclic guanosine monophosphate (cGMP) signaling pathway. The nitric oxide-donor sodium nitroprusside caused a reversible suppression of muscarine-stimulated sound production that could be blocked by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxaline-1-one (ODQ), which prevents the formation of cGMP by specifically inhibiting soluble guanylyl cyclase. Furthermore, injections of both the membrane-permeable cGMP analog 8-Br-cGMP and the specific inhibitor of the cGMP-degrading phosphodiesterase Zaprinast reversibly inhibited singing. To identify putative sources of nitric oxide, brains of Ch. biguttulus were subjected to both nitric oxide synthase immunocytochemistry and NADPH-diaphorase staining. Among other areas known to express nitric oxide synthase, both procedures consistently labeled peripheral layers in the upper division of the central body complex, suggesting that neurons supplying this neuropil contain nitric oxide synthase and may generate nitric oxide upon activation. Exposure of dissected brains to nitric oxide and 3-(5'hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) induced cGMP-associated immunoreactivity in both the upper and lower division. Therefore, both the morphological and pharmacological data presented in this study strongly suggest a contribution of the nitric oxide/cGMP signaling pathway to the central control of grasshopper sound production.

[Dementia and the Dutch Reading Tests for Adults]

The Dutch Adult Reading Test (DART) is a method to assess premorbid intelligence in brain damaged patients. This article describes a study in which subjects without dementia (n = 25), with mild dementia (n = 11) and moderate to severe dementia (n = 11) were tested with the DART. DART-scores of the no dementia and mild dementia groups did not differ, but were significantly lower in moderate to severe dementia. So, the DART appears to be sensitive to more severe cerebral pathology as occurs in more advanced dementia, but is very useful with patients with mild cognitive deterioration. For the first time the test-retest-reliability of the DART was determined: r = 0.87 to 0.98. Except in the severe dementia group the DART strongly correlates with educational level.

In situ thickness control during plasma deposition of hydrogenated amorphous silicon films by time-resolved microwave conductivity measurements

Transient photoconductivity measurements have been performed in situ during plasma-enhanced chemical vapor deposition of amorphous hydrogenated silicon by a contactless method that uses the change of the microwave reflection after laser pulse illumination. Through the use of the interference pattern of the amplitude of the transients of microwave reflection during the layer growth, the actual thickness of the amorphous film can be determined. In the case of crystalline silicon substrates, the change in the light absorption in the substrate modified by the growth of the amorphous layer is measured directly. An example of the optimization of antireflective layers on crystalline silicon substrates is shown. A good agreement is found between the experimental data and calculations of optical reflection and transmission on the multilayer structures.

The role of Jun transcription factor expression and phosphorylation in neuronal differentiation, neuronal cell death, and plastic adaptations in vivo

1. To investigate the role of the Jun transcription factors in neuronal differentiation, programmed neuronal cell death, and neuronal plasticity, we used phosphorothioate oligodeoxynucleotides (S-ODN) to inhibit selectively the expression of c-Jun, JunB, and JunD. 2. We have shown previously that in contrast to c-Jun, the JunB and JunD transcription factors are negative regulators of cell growth in various cell lines. Here we confirm this finding in primary human fibroblasts. 3. c-Jun and JunB are counterplayers not only with respect to proliferation, but also in cell differentiation. Since JunB expression is essential for neuronal differentiation, we analyzed possible posttranslational modifications of JunB after induction of PC-12 cell differentiation by nerve growth factor (NGF). 4. JunB was strongly phosphorylated after induction of PC-12 cell differentiation with NGF but not after stimulation of cell proliferation with serum. Thus, while cell proliferation is associated with c-Jun phosphorylation, cell differentiation is correlated with JunB phosphorylation. This supports the finding that c-Jun and JunB play antagonistic roles in both proliferation and differentiation. 5. The JunB transcription factor together with the c-Fos transcription factor is also induced in vivo in the suprachiasmatic nucleus (SCN) of rat brain after a light stimulus that induces resetting of the circadian clock. 6. Using antisense oligonucleotides injected into the third ventricle, we selectively cosuppressed the two transcription factors in vivo as shown by immunohistochemistry. Expression of c-Jun, JunD, and FosB was not affected. Inhibition of JunB and c-Fos expression prevented the light-induced phase shift of the circadian rhythm. In contrast, rats injected with a randomized control oligonucleotide showed the same phase shift as untreated animals. 7. In primary rat hippocampal cultures, anti-c-jun S-ODN selectively inhibited neuronal cell death and promoted neuronal survival. This indicates a causal role of c-Jun in programmed neuronal cell death. 8. These findings demonstrate the essential role of inducible transcription factors in the reprogramming of cells to a different functional state. Jun transcription factors play an essential role not only in fundamental processes such as cell proliferation, differentiation, and programmed neuronal cell death, but also in such complex processes as plastic adaptations in the mature brain. The inhibition of neuronal cell death by anti-c-jun S-ODN shows the great therapeutic potential of selective antisense oligonucleotides.

Inhibition of p185c-erbB-2 proto-oncogene expression by antisense oligodeoxynucleotides down-regulates p185-associated tyrosine-kinase activity and strongly inhibits mammary tumor-cell proliferation

The c-erbB-2 proto-oncogene codes for a 185-kd putative growth factor receptor that is highly homologous to but distinct from the epidermal growth factor (EGF) receptor. Amplification and overexpression of c-erbB-2 occurs in a number of human tumors, in some of which it is a negative prognostic factor. This study investigates the possibility of inhibiting tumor-cell proliferation by blocking c-erbB-2 expression in the human mammary carcinoma cell line SK-Br-3 using chemically modified antisense oligodeoxynucleotides. Expression of the p185c-erbB-2 protein product was selectively reduced within 48 hours and resulted in a growth arrest of SK-Br-3 cells. Biochemical studies of tyrosine-kinase and S6-kinase activities after antisense inhibition of c-erbB-2 show that p185c-erbB-2 activates the S6-kinase signalling pathway in a nonlinear, dose-dependent manner. This may be relevant for the design of therapeutic strategies involving the inhibition of c-erbB-2 (proto)- oncogene expression.

Opposite functions of jun-B and c-jun in growth regulation and neuronal differentiation

Induction of the jun-B and/or c-jun transcription factors is part of the immediate early response to diverse stimuli that induce alterations in cellular programs. While c-jun is a protooncogene whose expression is required for induction of cell proliferation, jun-B has recently been found to be induced by stimuli inducing differentiation in various cell lines. Furthermore, its expression is largely restricted to differentiating cells during embryogenesis. To determine the functional significance of these findings, we used antisense phosphorothioate oligodeoxynucleotides to inhibit expression of the two genes in proliferating and neuronally differentiating cells. While selective inhibition of c-jun expression reduced proliferation rates, inhibition of jun-B protein synthesis markedly increased proliferation in 3T3 fibroblasts, human mammary carcinoma cells and PC-12 pheochromocytoma cells, suggesting jun-B involvement in negative growth control. Neuronal differentiation of PC-12 cells induced by nerve growth factor (NGF) was prevented by inhibition of jun-B protein synthesis. PC-12 cells not only failed to grow neurites but also remained in the proliferative state. Furthermore, in cultured primary neurons from rat hippocampus, inhibition of jun-B expression, again, markedly reduced morphological differentiation. Conversely, inhibition of c-jun protein synthesis enhanced morphological differentiation of both primary neurons and PC-12 tumor cells. Thus, jun-B expression is required for neuronal differentiation and its balance with c-jun activity is involved in regulating key steps in proliferation and differentiation processes.