Publications by authors named "David A Lewis"

The dorsolateral prefrontal cortex (DLPFC) plays a crucial role in primate cognition, integrating multimodal information to generate top-down signals for cognitive control. During cognitive tasks, the DLPFC displays activity patterns of exceptional complexity and duration not observed in other cortical areas or species. These activity patterns are likely associated with the unique physiological and morphological properties of primate DLPFC pyramidal neurons (PNs).

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Female ticks deposit large egg clusters that range in size from hundreds to thousands. These egg clusters are restricted to a deposition site as they are stationary, usually under leaf litter and other debris. In some habitats, these sites can be exposed to periodic flooding.

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Background: In schizophrenia (SZ), impairments in cognitive functions, such as working memory, have been associated with alterations in certain types of inhibitory neurons that utilize the neurotransmitter -aminobutyric acid (GABA) in the dorsolateral prefrontal cortex (DLPFC). For example, GABA neurons that express parvalbumin (PV) or somatostatin (SST) have more prominent gene expression alterations than those that express vasoactive intestinal peptide (VIP). In bipolar disorder (BD) and major depression (MD), which exhibit similar, but less severe, cognitive impairments than SZ, alterations of transcript levels in GABA neurons have also been reported.

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The aim of this study was to make unstructured neuropathological data, located in the NeuroBioBank (NBB), follow Findability, Accessibility, Interoperability, and Reusability principles and investigate the potential of large language models (LLMs) in wrangling unstructured neuropathological reports. By making the currently inconsistent and disparate data findable, our overarching goal was to enhance research output and speed. The NBB catalog currently includes information from medical records, interview results, and neuropathological reports.

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Key mechanisms underlying chronic pain occur within the dorsal horn. Genome-wide association studies (GWASs) have identified genetic variants predisposed to chronic pain. However, most of these variants lie within regulatory non-coding regions that have not been linked to spinal cord biology.

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Article Synopsis
  • The study investigates how transcriptomes, or gene expression profiles, of two types of layer 3 pyramidal neurons (CP and IP) in the DLPFC change as macaque monkeys develop from prepuberty to adulthood, especially in relation to working memory and schizophrenia.
  • Using techniques like retrograde labeling and RNA sequencing, the researchers discovered that both neuron types exhibited distinct transcriptomes at all ages, with gene expression changes becoming more pronounced as the monkeys matured.
  • Findings suggest that IP neurons mature faster than CP neurons, indicating that these subtypes may play different roles in the development of working memory and could have varying vulnerabilities to schizophrenia during late postnatal development.
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Psychiatric disorders such as major depressive disorder (MDD), bipolar disorder (BD), and schizophrenia (SCZ) are characterized by altered cognition and mood, brain functions that depend on information processing by cortical microcircuits. We hypothesized that psychiatric disorders would display cell type-specific transcriptional alterations in neuronal subpopulations that make up cortical microcircuits: excitatory pyramidal (PYR) neurons and vasoactive intestinal peptide- (VIP), somatostatin- (SST), and parvalbumin- (PVALB) expressing inhibitory interneurons. Using laser capture microdissection followed by RNA sequencing (LCM-seq), we performed cell type-specific molecular profiling of subgenual anterior cingulate cortex, a region implicated in mood and cognitive control.

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The subgenual anterior cingulate cortex (sgACC) is a critical site for understanding the neural correlates of affect and emotion. While the activity of the sgACC is functionally homogenous, it is comprised of multiple Brodmann Areas (BAs) that possess different cytoarchitectures. In some sgACC BAs, Layer 5 is sublaminated into L5a and L5b which has implications for its projection targets.

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  • The study talks about how people with schizophrenia have problems with visuospatial working memory, which is the ability to remember visual information and how things relate to each other in space.
  • Researchers found that certain brain cells called PV and SST neurons don't work as well in people with schizophrenia, and this affects other brain cells called pyramidal neurons.
  • The scientists measured specific transcripts (kind of like instructions for how cells work) in different brain areas and found that people with schizophrenia had lower levels, which could cause the memory problems they experience.
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  • Transmission spectroscopy has been an essential method for studying exoplanet atmospheres, but recent studies question the assumption that the atmosphere is uniform, particularly for heated gas giants like WASP-39 b.
  • Using the James Webb Space Telescope, researchers detected differences in the morning and evening transmission spectra of WASP-39 b, finding that the evening spectra had significantly larger transit depths compared to the morning ones.
  • The findings suggest that the evening terminator is hotter and possibly clearer than the morning terminator, leading to implications about atmospheric circulation and cloud formation on the exoplanet.
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Unlabelled: In schizophrenia, layer 3 pyramidal neurons (L3PNs) in the dorsolateral prefrontal cortex (DLPFC) are thought to receive fewer excitatory synaptic inputs and to have lower expression levels of activity-dependent genes and of genes involved in mitochondrial energy production. In concert, these findings from previous studies suggest that DLPFC L3PNs are hypoactive in schizophrenia, disrupting the patterns of activity that are crucial for working memory, which is impaired in the illness. However, whether lower PN activity produces alterations in inhibitory and/or excitatory synaptic strength has not been tested in the primate DLPFC.

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Cognitive deficits from dorsolateral prefrontal cortex (dlPFC) dysfunction are common in neuroinflammatory disorders, including long-COVID, schizophrenia and Alzheimer's disease, and have been correlated with kynurenine inflammatory signaling. Kynurenine is further metabolized to kynurenic acid (KYNA) in brain, where it blocks NMDA and α7-nicotinic receptors (nic-α7Rs). These receptors are essential for neurotransmission in dlPFC, suggesting that KYNA may cause higher cognitive deficits in these disorders.

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Age-related dopamine (DA) neuron loss is a primary feature of Parkinson's disease. However, it remains unclear whether similar biological processes occur during healthy aging, albeit to a lesser degree. We therefore determined whether midbrain DA neurons degenerate during aging in mice and humans.

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Female ticks deposit large egg clusters that range in size from hundreds to thousands. These clusters are restricted to a deposition site, usually under leaf litter and other debris. These sites can be exposed to periodic flooding, where the cluster of tick eggs can float to the surface or remain underneath organic debris entirely underwater.

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  • The study investigates how genetic variants in specific brain cell regulatory elements contribute to disease risk by analyzing chromatin accessibility in neurons and non-neurons from human brain samples.
  • Researchers found 34,539 open chromatin areas, with only 10.4% being common between neuron and non-neuron cells, indicating that genetic regulation varies by cell type.
  • By identifying 476 regulatory variants with functional impacts, the research enhances understanding of brain gene regulation and its link to diseases, offering valuable insights into potential therapeutic targets.
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Importance: The risk of mental disorders is consistently associated with variants in CACNA1C (L-type calcium channel Cav1.2) but it is not known why these channels are critical to cognition, and whether they affect the layer III pyramidal cells in the dorsolateral prefrontal cortex that are especially vulnerable in cognitive disorders.

Objective: To examine the molecular mechanisms expressed in layer III pyramidal cells in primate dorsolateral prefrontal cortices.

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Introduction: Gonorrhoea, the sexually transmissible infection caused by , has a substantial impact on sexual and reproductive health globally with an estimated 82 million new infections each year worldwide. antimicrobial resistance continues to escalate, and disease control is largely reliant on effective therapy as there is no proven effective gonococcal vaccine available. However, there is increasing evidence from observational cohort studies that the serogroup B meningococcal vaccine four-component meningitis B vaccine (4CMenB) (Bexsero), licensed to prevent invasive disease caused by , may provide cross-protection against the closely related bacterium .

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Dysfunction of the cortical dorsal visual stream and visuospatial working memory (vsWM) network in individuals with schizophrenia (SZ) likely reflects alterations in both excitatory and inhibitory neurotransmission within nodes responsible for information transfer across the network, including primary visual (V1), visual association (V2), posterior parietal (PPC), and dorsolateral prefrontal (DLPFC) cortices. However, the expression patterns of ionotropic glutamatergic and GABAergic receptor subunits across these regions, and alterations of these patterns in SZ, have not been investigated. We quantified transcript levels of key subunits for excitatory N-methyl-D-aspartate receptors (NMDARs), excitatory alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs), and inhibitory GABA receptors (GABAARs) in postmortem total gray matter from V1, V2, PPC, and DLPFC of unaffected comparison (UC) and matched SZ subjects.

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Understanding the mechanism of interfacial enzyme kinetics is critical to the development of synthetic biological systems for the production of value-added chemicals. Here, the interfacial kinetics of the catalysis of β-nicotinamide adenine dinucleotide (NAD)-dependent enzymes acting on NAD tethered to the surface of silica nanoparticles (SiNPs) has been investigated using two complementary and supporting kinetic approaches: enzyme excess and reactant (NAD) excess. Kinetic models developed for these two approaches characterize several critical reaction steps including reversible enzyme adsorption, complexation, decomplexation, and catalysis of the surface-bound enzyme/NAD complex.

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Synaptic function is directly reflected in quantifiable ultrastructural features using electron microscopy (EM) approaches. This coupling of synaptic function and ultrastructure suggests that synaptic function can be inferred from EM analysis of human brain tissue. To investigate this, we employed focused ion beam-scanning electron microscopy (FIB-SEM), a volume EM (VEM) approach, to generate ultrafine-resolution, three-dimensional (3D) micrographic datasets of postmortem human dorsolateral prefrontal cortex (DLPFC), a region with cytoarchitectonic characteristics distinct to human brain.

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  • Despite the notable advancements in immunotherapy for cancer, only a small percentage (less than 20%) show lasting responses to immune checkpoint blockade, leading researchers to consider combination therapies that target multiple immune evasion strategies.
  • Researchers analyzed data from over 1,000 tumors across ten cancers to identify seven distinct immune subtypes, examining their unique genomic, epigenetic, transcriptomic, and proteomic characteristics.
  • By investigating kinase activities linked to these immune subtypes, the study uncovered potential therapeutic targets that could improve future immunotherapy approaches and precision medicine.
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In brain, the striatum is a heterogenous region involved in reward and goal-directed behaviors. Striatal dysfunction is linked to psychiatric disorders, including opioid use disorder (OUD). Striatal subregions are divided based on neuroanatomy, each with unique roles in OUD.

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Deficient gamma oscillations in prefrontal cortex (PFC) of individuals with schizophrenia appear to involve impaired inhibitory drive from parvalbumin-expressing interneurons (PVIs). Inhibitory drive from PVIs is regulated, in part, by RNA binding fox-1 homolog 1 (Rbfox1). Rbfox1 is spliced into nuclear or cytoplasmic isoforms, which regulate alternative splicing or stability of their target transcripts, respectively.

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  • Dorsolateral prefrontal cortex (DLPFC) dysfunction in schizophrenia is linked to smaller layer 3 pyramidal neurons (L3PNs) and reduced mitochondrial energy production markers, but previous methods to study these changes were biased.
  • The study used a novel approach combining fluorescent in situ hybridization and immunohistochemistry to accurately identify and quantify L3PNs in schizophrenia and compared them to unaffected subjects.
  • Results showed that L3PNs in schizophrenia were 8.7% smaller with 16.7% lower levels of energy production mRNA, indicating that the morphological changes in neurons may lead to decreased energy production markers in the illness.
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