Parallel Profiles Research Articles

Excessive applicator radiation leakage for a common therapeutic kilovoltage system.

The objective of this work is to characterise out- of- field leakage radiation emanating from clinical applicators of the WOmed T-200 kilovoltage therapy machine. To identify points of leakage, radiosensitive film was affixed to the walls and base plate of each applicator. Quantitative assessment of leakage radiation was conducted with a 0.23 cm3 ionisation chamber following the International Electrotechnical Commission standard. Film was also used to illustrate leakage distribution in the patient plane. Angular and energy dependences of the leakage radiation were quantified as well as a two-dimensional leakage profile in the plane parallel to one applicator. Leakage was found when the diameter of primary collimator of the kV tube exceeded the external dimension of the applicator wall. In the patient plane all applicators showed similar leakage rates with the leakage distribution dependent upon applicator design. Mean patient plane leakage was 1.37% of central axis air kerma rate, exceeding the 0.5% limit specified in the standard. Leakage was shown to be profoundly energy dependent with maximum leakage of 11.8% for the 200 kV beam, 1.3% for 150 kV and 0.2% for 100 kV. Angular dependence measurements showed a 10.3% change in leakage between the minimum and maximum positions. The combination of shielding thickness, primary collimator design and applicator dimensions permits unwanted radiation to contribute dose outside the treatment field when energies ≥150 kV are used. Even carefully designed modern kv therapy systems can exhibit leakage in some areas. Thorough assessment of leakage is needed prior to release for clinical use.

367O - Parallel identification and profiling of tumour antigen-specific T-cells for biomarker discovery by mass cytometry

367O - Parallel identification and profiling of tumour antigen-specific T-cells for biomarker discovery by mass cytometry

Shear wave reflection seismic yields subsurface dissolution and subrosion patterns: application to the Ghor Al-Haditha sinkhole site, Dead Sea, Jordan

Abstract. Near-surface geophysical imaging of alluvial fan settings is a challenging task but crucial for understating geological processes in such settings. The alluvial fan of Ghor Al-Haditha at the southeast shore of the Dead Sea is strongly affected by localized subsidence and destructive sinkhole collapses, with a significantly increasing sinkhole formation rate since ca. 1983. A similar increase is observed also on the western shore of the Dead Sea, in correlation with an ongoing decline in the Dead Sea level. Since different structural models of the upper 50 m of the alluvial fan and varying hypothetical sinkhole processes have been suggested for the Ghor Al-Haditha area in the past, this study aimed to clarify the subsurface characteristics responsible for sinkhole development.For this purpose, high-frequency shear wave reflection vibratory seismic surveys were carried out in the Ghor Al-Haditha area along several crossing and parallel profiles with a total length of 1.8 and 2.1 km in 2013 and 2014, respectively. The sedimentary architecture of the alluvial fan at Ghor Al-Haditha is resolved down to a depth of nearly 200 m at a high resolution and is calibrated with the stratigraphic profiles of two boreholes located inside the survey area.The most surprising result of the survey is the absence of evidence of a thick (> 2–10 m) compacted salt layer formerly suggested to lie at ca. 35–40 m depth. Instead, seismic reflection amplitudes and velocities image with good continuity a complex interlocking of alluvial fan deposits and lacustrine sediments of the Dead Sea between 0 and 200 m depth. Furthermore, the underground section of areas affected by sinkholes is characterized by highly scattering wave fields and reduced seismic interval velocities. We propose that the Dead Sea mud layers, which comprise distributed inclusions or lenses of evaporitic chloride, sulfate, and carbonate minerals as well as clay silicates, become increasingly exposed to unsaturated water as the sea level declines and are consequently destabilized and mobilized by both dissolution and physical erosion in the subsurface. This new interpretation of the underlying cause of sinkhole development is supported by surface observations in nearby channel systems. Overall, this study shows that shear wave seismic reflection technique is a promising method for enhanced near-surface imaging in such challenging alluvial fan settings.

Spiral Sampling Method for Quantitative Estimates of Joint Roughness Coefficient of Rock Fractures

Abstract Representative sampling of surface roughness is essential for reliable and consistent estimates of joint roughness coefficients (JRCs) by quantitative formulations. The most commonly used sampling method is the straight-line profiling along a predetermined shear direction. Because of anisotropy and nonuniform distribution of roughness features on natural joint surfaces, this method may work well only when the potential shear direction is known or can be predicted. However, there are no guidelines for the density of parallel straight-line profiles and how these can be synthesized into a representative profile. This article presents a spiral sampling method that addresses the shortcomings of the straight-line method. The roughness parameters derived from the spiral scanlines are closely correlated with the JRC values back-calculated from direct shear tests.

Evaluation of methodologies for microRNA biomarker detection by next generation sequencing

ABSTRACTIn recent years, microRNAs (miRNAs) in tissues and biofluids have emerged as a new class of promising biomarkers for numerous diseases. Blood-based biomarkers are particularly desirable since serum or plasma is easily accessible and can be sampled repeatedly. To comprehensively explore the biomarker potential of miRNAs, sensitive, accurate and cost-efficient miRNA profiling techniques are required. Next generation sequencing (NGS) is emerging as the preferred method for miRNA profiling; offering high sensitivity, single-nucleotide resolution and the possibility to profile a considerable number of samples in parallel. Despite the excitement about miRNA biomarkers, challenges associated with insufficient characterization of the sequencing library preparation efficacy, precision and method-related quantification bias have not been addressed in detail and are generally underappreciated in the wider research community.Here, we have tested in parallel four commercially available small RNA sequencing kits against a cohort of samples comprised of human plasma, human serum, murine brain tissue and a reference library containing ~ 950 synthetic miRNAs. We discuss the advantages and limits of these methodologies for massive parallel microRNAs profiling. This work can serve as guideline for choosing an adequate library preparation method, based on sensitivity, specificity and accuracy of miRNA quantification, workflow convenience and potential for automation.

PO-124 PTTG and PBF functionally interact with P53 and predict overall survival in head and neck cancer

IntroductionReceptor tyrosine kinases (RTKs) play important roles in cellular proliferation and differentiation. In addition, RTKs reveal oncogenic potential when their kinase activities are constitutively enhanced by point mutation, amplification, or rearrangement of the corresponding genes. We are investigating ALK (Anaplastic Lymphoma Kinase) tyrosine kinase in neuroblastoma (NB) - the most frequently occurring extracranial tumour in children, where ALK activating mutations are found.In this study we performed phosphoproteomic and a gene signature profiling of ALK activity from several different neuroblastoma cells comparing treatment with the first and third generations ALK inhibitors.Material and methodsCrizotinib was one of the first ALK TKIs to be described; however the response in patients with ALK positive NB was poor. In contrast, robust and sustained clinical responses we seen in ALK rearranged IMT. Lorlatinib is a third generation ALK TKI with very positive responses in NSCLC. We treated two ALK addicted (CLB-BAR, CLB-GE) and one ALK non-addicted (SK-N-AS) NB cell lines with either crizotinib or lorlatinib and performed phosphoproteomic and RNAseq profiling to identify common targets for future combinational treatment for patients.Results and discussionsProfiling of ALK addicted CLB-BAR and CLB-GE cell lines led to the identification of 3345 and 2252 phosphoproteins, respectively. Phosphorylation of the ALK receptor itself was decreased in both lines upon treatment with crizotinib or lorlatinib. Parallel RNAseq profiling was performed at 24 hours. Comparison with non-treated controls revealed 19 232 differently expressed genes. In ALK addicted cells phosphoproteomic analysis revealed more than 50 proteins that were dephosphorylated upon treatment with ALK TKIs. More than 400 genes were downregulated, and more than 600 were upregulated, upon treatment with either crizotinib or lorlatinib. As an outcome we obtained a list of predicted targets for further analysis. We focused on validation of downstream signalling molecules such as: FOXO3a/4, DUSP4 and ETV3/4.ConclusionIn this study we established and compared phosphoproteomic and gene signature profiles of ALK activity in NB cells employing first and third generation ALK TKIs. This analysis has unveiled a number of leads for novel combinatorial treatment strategies for NB patients as well as an increased understanding ALK dependant signalling processes.

Abstract 1180: Quantifying melanoma drug resistance and tumor heterogeneity by live cell interferometry

Abstract Melanoma is the most aggressive type of skin cancer. Tumor heterogeneity and drug resistance are significant obstacles to survival benefits from mutation-targeted therapy. Over 50% of metastatic melanomas harbor V600BRAF mutations. Targeting of MUTBRAF melanoma with BRAF inhibitor monotherapy or the combination of BRAF and MEK inhibitors leads to a high rate of initial responses, but adaptive and acquired resistance frequently leads to clinical relapse. Although the presence of V600BRAF mutations guides the selection of therapy with MAPK inhibitors, methods to track preexisting and adaptive resistance and thereby predict response patterns, or to use this new information to modify therapy, are still lacking. Here, we aimed to develop a rapid, massively parallel tumor cell profiling method, based on Live Cell Interferometry (LCI), to quantify heterogeneous single tumor cell responses and emergent drug resistance. LCI is an ex vivo imaging approach that quantifies changes in total cell biomass, biomass motion, or cell stiffness over time. We report a novel high-throughput screening version of the LCI platform, HSLCI, which rapidly profiles changes in biomass in BRAF inhibitor (BRAFi)-sensitive, parental melanoma cell lines and their isogenic, BRAFi-resistant sub-lines. We show reproducible results from two different HSLCI platforms at two institutions and generate biomass kinetic signatures capable of discriminating between BRAFi-sensitive and -resistant melanoma cells within 24 hours. Our measurements require no fluorescence or dye labeling and are faster than field-standard growth inhibition assays. The accuracy and speed of HSLCI in profiling tumor cell heterogeneity and therapy resistance are promising features of potential tools to guide patient therapeutic selections. Citation Format: Kevin A. Leslie, Dian Huang, Graeme Murray, Daniel Guest, Irena J. Roy, Marco Piva, Gatien Moriceau, Roger S. Lo, Michael A. Teitell, Jason C. Reed. Quantifying melanoma drug resistance and tumor heterogeneity by live cell interferometry [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1180.

Abstract 4869: Discovery and characterization of highly potent and selective USP7 inhibitors and benchmarking against clinical MDM2 antagonists

Abstract Given the importance of USP7 in known oncogenic pathways and its emerging role in immuno-oncology, the identification of USP7 inhibitors has attracted considerable interest in the scientific community. However, despite substantial efforts over the past 15 years, the development of genuine deubiquitinase (DUB) inhibitors, which exhibit both drug-like properties and a well-defined mechanism of action, has proven particularly challenging. In this study, we report the application of UbiPlexTM, our purpose-built DUB drug discovery platform, to USP7. In particular, we detail the identification, optimization and detailed characterization of a new class of non-covalent and highly potent USP7 inhibitors (IC50 < 10 nM). In addition, these inhibitors have shown exquisite selectivity for USP7 over other DUBs and proteases. We also disclose high-resolution co-crystal structures of USP7 in complex with these inhibitors that reveal an allosteric mode of binding. Further profiling in cells demonstrated potent target engagement with endogenous USP7 (EC50 <20 nM). In line with the known biology of USP7, this effect induced the proteasomal degradation of MDM2, concomitant stabilization of p53 and induction of p21 in multiple cell lines. The identification and parallel profiling of inactive enantiomers further validated the on-target effect of our lead molecules. Finally, we report the identification of cell lines hyper-sensitive (EC50 < 30 nM) to USP7 inhibitors in both haematological and solid cancer cell line settings and demonstrate equal or superior activity when compared to clinically relevant MDM2 antagonists. In summary, this work exemplifies the tractability and druggability of USP7 as a cancer target and provides new insights and directions for the potential clinical development of USP7 inhibitors. Citation Format: Gerald Gavory, Colin O'Dowd, Elias Arkoudis, Oliver Barker, Eamon Cassidy, Anthony Dossang, Jakub Flasz, Matt Helm, Caroline Hughes, Keeva McClelland, Hugues Miel, Ewa Odrzywol, Natalie Page, Tim Harrison. Discovery and characterization of highly potent and selective USP7 inhibitors and benchmarking against clinical MDM2 antagonists [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4869.

MiR-181a/b induce the growth, invasion, and metastasis of neuroblastoma cells through targeting ABI1.

Neuroblastoma is a pediatric malignancy, and the clinical phenotypes range from localized tumors with excellent outcomes to widely metastatic disease in which long-term survival is approximately 40%, despite intensive therapy. Emerging evidence suggests that aberrant miRNA regulation plays a role in neuroblastoma, but the miRNA functions and mechanisms remain unknown. miR-181 family members were detected in 32 neuroblastoma patients, and the effects of miR-181a/b on cell viability, invasion, and migration were evaluated in vitro and in vivo. A parallel global mRNA expression profile was obtained for neuroblastoma cells overexpressing miR-181a. The potential targets of miR-181a/b were validated. miR-181a/b expression levels were positively associated with MYCN amplification and neuroblastoma aggressiveness. Moreover, ectopic miR-181a/b expression significantly induced the growth and invasion of neuroblastoma cells in vitro and in vivo. Microarray analysis revealed that mRNAs were consistently downregulated after miR-181a overexpression, leading to cell migration. In addition, the expression of ABI1 was suppressed by miR-181a/b, and ABI1 was validated as a direct target of miR-181a/b. We concluded that miR-181a/b were significantly upregulated in aggressive neuroblastoma, which enhanced its tumorigenesis and progression by suppressing the expression of ABI1.

Concordance of 24-h intraocular pressure curve in patients with untreated unilateral primary open-angle glaucoma.

The present study aimed to assess the concordance of 24-h intraocular pressure (IOP) curves between glaucomatous and contralateral eyes for patients with untreated unilateral primary open-angle glaucoma (POAG). A total of 32 patients with unilateral POAG and 32 age-matched normal subjects were enrolled. The IOP measurements were performed every 2 h over a 24-h period. The concordance of the 24-h IOP curves was assessed via the correlation coefficient (r), intraclass correlation coefficient (ICC) and repeated-measures analysis of variance (ANOVA). No significant difference was identified between all IOPs, as well as the mean, peak and trough IOP or IOP fluctuations of the paired eyes in the two groups. The strength of association of all IOPs was moderate in the glaucoma group (r, 0.752-0.867) and the normal controls (r, 0.625-0.873). IOP readings at each time-point indicated a high agreement in the glaucoma group (ICC, 0.857-0.929) and the normal controls (ICC, 0.768-0.932). Repeated-measures ANOVA indicated that the 24-h IOP curves of the paired eyes had parallel profiles in the two study groups (P=0.837 and P=0.897, respectively). The glaucoma patients had significantly higher proportions of all IOPs displaying absolute differences of ≥2 and ≥3 mmHg (46.09 vs. 35.68%, P<0.001; 29.69 vs. 12.50%, P<0.001, respectively). In conclusion, the 24-h IOP curves of the paired eyes had parallel profiles in unilateral glaucoma patients and normal subjects. However, unilateral glaucoma patients had a significantly larger proportion of IOP differences of ≥2 and ≥3 mmHg.

Regional and residual gravity anomaly separation using the singular spectrum analysis-based low pass filtering: a case study from Nagpur, Maharashtra, India

We present here a singular spectrum analysis (SSA)-based low pass filtering algorithm for regional and residual gravity anomaly separation. The data adaptive decomposition in SSA frequency filtering algorithm facilitates reduction of the artefacts in the filtering of the non-linear and non-stationary gravity data. Initially, the method was tested on synthetic gravity data representing combined response of regional and residual components derived from the geological structures like infinite horizontal layers, intrusive dykes, deep-seated faults and volcanic intrusive bodies and compared with fast Fourier transform (FFT) wavenumber and wavelet-based filtering techniques. The results show that SSA-based filtered output exhibits a better match with pure synthetic data than the output generated from the FFT and wavelet filtering methods. The underlying method was then applied to two parallel gravity profiles of real data from the Umred coalfield, Nagpur, Maharashtra, India. Further, the SSA-based filtered regional anomaly was modelled using Geosoft GM-SYS software to construct the model of crustal structure of the study region. In essence, the modelling results suggest the following: (i) a basin-type graben structure with variable trap and sedimentary thicknesses and (ii) deep seated faults on either sides of the basin. These results correlate fairly well with known regional geology attesting the authenticity of the regional models generated from the two gravity profiles, which also agree well with each other. We, therefore, conclude that the SSA-based filtering technique is robust for regional gravity anomaly separation and could be effectively exploited for filtering other geophysical data.

A Single-Cell Transcriptome Atlas of the Mouse Glomerulus.

Background Three different cell types constitute the glomerular filter: mesangial cells, endothelial cells, and podocytes. However, to what extent cellular heterogeneity exists within healthy glomerular cell populations remains unknown.Methods We used nanodroplet-based highly parallel transcriptional profiling to characterize the cellular content of purified wild-type mouse glomeruli.Results Unsupervised clustering of nearly 13,000 single-cell transcriptomes identified the three known glomerular cell types. We provide a comprehensive online atlas of gene expression in glomerular cells that can be queried and visualized using an interactive and freely available database. Novel marker genes for all glomerular cell types were identified and supported by immunohistochemistry images obtained from the Human Protein Atlas. Subclustering of endothelial cells revealed a subset of endothelium that expressed marker genes related to endothelial proliferation. By comparison, the podocyte population appeared more homogeneous but contained three smaller, previously unknown subpopulations.Conclusions Our study comprehensively characterized gene expression in individual glomerular cells and sets the stage for the dissection of glomerular function at the single-cell level in health and disease.

Parallel genomic and immune profiling of relapsed and metastatic osteosarcoma to reveal bases of low immunogenicity.

10520Background: Despite the high levels of point mutations, rearrangements, and other genomic instability events such as kataegis and chromothripsis, immune checkpoint inhibitors have shown limite...

Parallel Genome-wide Profiling of Coding and Non-coding RNAs to Identify Novel Regulatory Elements in Embryonic and Maturated Heart

Heart development is a complex process, tightly regulated by numerous molecular mechanisms. Key components of the regulatory network underlying heart development are transcription factors (TFs) and microRNAs (miRNAs), yet limited investigation of the role of miRNAs in heart development has taken place. Here, we report the first parallel genome-wide profiling of polyadenylated RNAs and miRNAs in a developing murine heart. These data enable us to identify dynamic activation or repression of numerous biological processes and signaling pathways. More than 200 miRNAs and 25 long non-coding RNAs were differentially expressed during embryonic heart development compared to the mature heart; most of these had not been previously associated with cardiogenesis. Integrative analysis of expression data and potential regulatory interactions suggested 28 miRNAs as novel regulators of embryonic heart development, representing a considerable expansion of the current repertoire of known cardiac miRNAs. To facilitate follow-up investigations, we constructed HeartMiR (http://heartmir.sysbiolab.eu), an open access database and interactive visualization tool for the study of gene regulation by miRNAs during heart development.

Duality based interpretation of uniqueness in the trilinear decompositions

Application of trilinearity constraint in curve resolution of three-way data sets can play an important role in the triadic decompositions. Matrix Augmented-MCR-ALS is a two-way analysis method while its incorporation with the trilinearity constraint can provide a triadic decomposition like PARAFAC model. Trilinearity is a very strong constraint which can lead unique decomposition under mild conditions. Additionally, duality concept represents a relation between column and row spaces of bilinear data matrices. Thus, in case of a unique solution or uniqueness condition, the duality concept is a general and powerful approach for visualization. Based on the duality concept, it is necessary to define a particular hyper-plane in the dual abstract space in order to have a unique profile. It is discussed and visualized that the trilinearity constraint with the idea of parallel proportional profiles can define a particular hyper-plane in the space causing/leading to uniqueness in the dual space. Several simulated and real data sets were exemplified to show the ability of the duality concept to study and visualize the uniqueness due to the application of trilinearity constraint.

Effect of fiber sources on fatty acids profile, glycemic index, and phenolic compound content of in vitro digested fortified wheat bread.

In this study, some dietary fiber (DF) sources were investigated as fortifiers of wheat bread: oat (OB), flax (FB), and apple (AB). Adding oat and flax fibers to bread significantly changed the fatty acid profiles. OB was highest in oleic acid (33.83% of lipids) and linoleic acid (24.31% of lipids). Only in FB, γ-linolenic fatty acid was present in a significant amount-18.32%. The bioaccessibility trails revealed that the DF slow down the intake of saturated fatty acids. PUFA were least bioaccessible from all fatty acids groups in the range of (72% in OB to 87% in FB). The control bread had the greatest value (80.5) and was significantly higher than values for OB, FB, and AB in terms of glycemic index. OB, FB and AB addition led to obtain low glycemic index. AB had a significant highest value of total phenolic (897.2mg/kg) with the lowest values in FB (541.2mg/kg). The only significant lowering of caloric values in this study was observed in AB. The study could address the gap in the area of research about taking into consideration glycemic index, fatty acid profile and phenolic content in parallel in terms of DF application in breads.

On the Salt Water Intrusion into the Durusu Lake, Istanbul: A Joint Central Loop TEM And Multi-Electrode ERT Field Survey

Durusu Lake is the biggest and most important freshwater source supplying drinking water to the European side of Istanbul. In this study, electrical resistivity tomography (ERT) and transient electromagnetic (TEM) measurements were applied to detect a possible salt water intrusion into the lake and to delineate the subsurface structure in the north of Durusu Lake. The ERT and TEM measurements were carried out along six parallel profiles extending from the sea coast to the lake shore on the dune barrier. TEM data were interpreted using different 1-D inversion methods such as Occam, Marquardt, and laterally constrained inversion (LCI). ERT data were interpreted using 2-D inversion techniques. The inversion results of ERT and TEM data were shown as resistivity depth sections including topography. The sand layer spreading over the basin has a resistivity of 150–400 Ωm with a thickness of 5–10 m. The sandy layer with clay, silt, and gravel has a resistivity of 15–100 Ωm and a thickness of 10–40 m followed by a clay layer of a resistivity below 10 Ωm. When the inversion of these data is interpreted along with the hydrogeology of the area, it is concluded that the salt water intrusion along the dune barrier is not common and occurs at a particular area where the distance between lake and sea is very close. Using information from boreholes around the lake, it was verified that the common conductive region at depths of 30 m or more consists of clay layers and clay lenses.

Single-cell RNA-seq of rheumatoid arthritis synovial tissue using low-cost microfluidic instrumentation

Droplet-based single-cell RNA-seq has emerged as a powerful technique for massively parallel cellular profiling. While this approach offers the exciting promise to deconvolute cellular heterogeneity in diseased tissues, the lack of cost-effective and user-friendly instrumentation has hindered widespread adoption of droplet microfluidic techniques. To address this, we developed a 3D-printed, low-cost droplet microfluidic control instrument and deploy it in a clinical environment to perform single-cell transcriptome profiling of disaggregated synovial tissue from five rheumatoid arthritis patients. We sequence 20,387 single cells revealing 13 transcriptomically distinct clusters. These encompass an unsupervised draft atlas of the autoimmune infiltrate that contribute to disease biology. Additionally, we identify previously uncharacterized fibroblast subpopulations and discern their spatial location within the synovium. We envision that this instrument will have broad utility in both research and clinical settings, enabling low-cost and routine application of microfluidic techniques.

ScNMT-seq enables joint profiling of chromatin accessibility DNA methylation and transcription in single cells

Parallel single-cell sequencing protocols represent powerful methods for investigating regulatory relationships, including epigenome-transcriptome interactions. Here, we report a single-cell method for parallel chromatin accessibility, DNA methylation and transcriptome profiling. scNMT-seq (single-cell nucleosome, methylation and transcription sequencing) uses a GpC methyltransferase to label open chromatin followed by bisulfite and RNA sequencing. We validate scNMT-seq by applying it to differentiating mouse embryonic stem cells, finding links between all three molecular layers and revealing dynamic coupling between epigenomic layers during differentiation.

Massively Parallel Single Nucleus Transcriptional Profiling Defines Spinal Cord Neurons and Their Activity during Behavior

SUMMARYTo understand the cellular basis of behavior, it is necessary to know the cell types that exist in the nervous system and their contributions to function. Spinal networks are essential for sensory processing and motor behavior and provide a powerful system for identifying the cellular correlates of behavior. Here, we used massively parallel single nucleus RNA sequencing (snRNA-seq) to create an atlas of the adult mouse lumbar spinal cord. We identified and molecularly characterized 43 neuronal populations. Next, we leveraged the snRNA-seq approach to provide unbiased identification of neuronal populations that were active following a sensory and a motor behavior, using a transcriptional signature of neuronal activity. This approach can be used in the future to link single nucleus gene expression data with dynamic biological responses to behavior, injury, and disease.