Biology subjects

Tian, L.

Publications and source records attributed to Tian, L..

At least 127 records · Page 7Linked to original sources

bioRxiv2022

EDoF-Miniscope: pupil engineering for extended depth-of-field imaging in a fluorescence miniscope

Extended depth of field (EDoF) microscopy has emerged as a powerful solution to greatly increase the access into neuronal populations in table-top imaging platforms. Here, we present EDoF-Miniscope, which integrates an optimized thin and lightweight binary diffractive optical element (DOE) onto the gradient refractive index (GRIN) lens of a head-mounted fluorescence miniature microscope, i.e. "miniscope". We achieve an alignment accuracy of 70 m to allow a 2.8X depth-of-field extension between the twin foci. We optimize the phase profile across the whole back aperture through a genetic algorithm that considers the primary GRIN lens aberrations, optical property of the submersion media, and axial intensity loss from tissue scattering in a Fourier optics forward model. Compared to other computational miniscopes, our EDoF-Miniscope produces high-contrast signals that can be recovered by a simple algorithm and can successfully capture volumetrically distributed neuronal signals without significantly compromising the speed, signal-to-noise, signal-to-background, and maintain a comparable 0.9-m lateral spatial resolution and the size and weight of the miniature platform. We demonstrate the robustness of EDoF-Miniscope against scattering by characterizing its performance in 5-m and 10-m beads embedded in scattering phantoms. We demonstrate that EDoF-Miniscope facilitates deeper interrogations of neuronal populations in a 100-m thick mouse brain sample, as well as vessels in a mouse brain. Built from off-the-shelf components augmented by a customizable DOE, we expect that this low-cost EDoF-Miniscope may find utility in a wide range of neural recording applications.

bioengineering↗

bioRxiv2022

Benchmarking long-read RNA-sequencing analysis tools using in silico mixtures

The current lack of benchmark datasets with inbuilt ground-truth makes it challenging to compare the performance of existing long-read isoform detection and differential expression analysis workflows. Here, we present a benchmark experiment using two human lung adenocarcinoma cell lines that were each profiled in triplicate together with synthetic, spliced, spike-in RNAs ("sequins"). Samples were deeply sequenced on both Illumina short-read and Oxford Nanopore Technologies long-read platforms. Alongside the ground-truth available via the sequins, we created in silico mixture samples to allow performance assessment in the absence of true positives or true negatives. Our results show that, StringTie2 and bambu outperformed other tools from the 6 isoform detection tools tested, DESeq2, edgeR and limma-voom were best amongst the 5 differential transcript expression tools tested and there was no clear front-runner for performing differential transcript usage analysis between the 5 tools compared, which suggests further methods development is needed for this application.

bioinformatics↗

bioRxiv2022

The Spatial Organization of Bacterial Transcriptional Regulatory Networks

Transcriptional regulatory network (TRN) is the central pivot of a prokaryotic organism to receive, process and respond to internal and external environmental information. However, little is known about its spatial organization so far. In recent years, chromatin interaction data of bacteria such as Escherichia coli and Bacillus subtilis have been published, making it possible to study the spatial organization of bacterial transcriptional regulatory networks. By combining TRNs and chromatin interaction data of E. coli and B. subtilis, we explored the spatial organization characteristics of bacterial TRNs in many aspects such as regulation directions (positive and negative), central nodes (hubs, bottlenecks), hierarchical levels (top, middle, bottom) and network motifs (feed-forward loops and single input modules) of the TRNs and found that the bacterial TRNs have a variety of stable spatial organization features under different physiological conditions which may be closely related with basic life activities. Our findings provided new insights into the connection between transcriptional regulation and the spatial organization of chromosome in bacteria, and might serve as a foundation for spatial-distance-based gene circuit design in synthetic biology.

systems biology↗

bioRxiv2022

Micropatterned Organoids Enable Modeling of the Earliest Stages of Human Cardiac Vascularization

Although model organisms have provided insight into the earliest stages of cardiac vascularization, we know very little about this process in humans. Here we show that spatially micropatterned human pluripotent stem cells (hPSCs) enable in vitro modeling of this process, corresponding to the first three weeks of in vivo human development. Using four hPSC fluorescent reporter lines, we create cardiac vascular organoids (cVOs) by identifying conditions that simultaneously give rise to spatially organized and branched vascular networks within endocardial, myocardial, and epicardial cells. Using single-cell transcriptomics, we show that the cellular composition of cVOs resembles that of a 6.5 post-conception week (PCW) human heart. We find that NOTCH and BMP pathways are upregulated in cVOs, and their inhibition disrupts vascularization. Finally, using the same vascular-inducing factors to create cVOs, we produce hepatic vascular organoids (hVOs). This suggests there is a conserved developmental program for creating vasculature within different organ systems. Graphic Abstract O_FIG O_LINKSMALLFIG WIDTH=159 HEIGHT=200 SRC="FIGDIR/small/499233v1_ufig1.gif" ALT="Figure 1"> View larger version (32K): org.highwire.dtl.DTLVardef@17b265org.highwire.dtl.DTLVardef@1c1113eorg.highwire.dtl.DTLVardef@531c18org.highwire.dtl.DTLVardef@596bd2_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2022

Single-shot Volumetric Chemical Imaging by Mid- Infrared Photothermal Fourier Light Field Microscopy

Three-dimensional molecular imaging of living organisms and cells plays a significant role in modern biology. Yet, current volumetric imaging modalities are largely fluorescence-based and thus lack chemical content information. Mid-infrared photothermal microscopy as a new chemical imaging technology provides infrared spectroscopic information at sub-micrometer spatial resolution. Here, by harnessing thermosensitive fluorescent dyes to sense the mid-infrared photothermal effect, we demonstrate mid-infrared photothermal Fourier light field (MIP-FLF) microscopy for single-shot volumetric infrared spectroscopic imaging at the speed of 8 volumes per second and sub-micron spatial resolution. Protein contents in bacteria and lipid droplets in living pancreatic cancer cells are visualized. Altered lipid metabolism in drug-resistant pancreatic cancer cells is observed with the MIP-FLF microscope.

biochemistry↗

bioRxiv2022

Bumetanide increases microglia-interneuron contact following traumatic brain injury

ObjectiveThe Na-K-Cl cotransporter (NKCC1) inhibitor bumetanide has prominent positive effects on the pathophysiology of many neurological disorders. Here we studied whether bumetanide could influence post-traumatic cognitive decline and inflammatory processes by regulating astrocyte and microglia activation. MethodControlled cortical impacted (CCI) animals were treated with bumetanide during the first post-CCI week. Immunochemistry, flow cytometry, immunoassay, and in vivo imaging were used to study astrocytic and microglial morphology and phenotype as well as adult neurogenesis. Telemetric electroencephalograms and cognitive behavioral test were performed at one-month post CCI. ResultsBumetanide prevented CCI-induced decrease in hippocampal neurogenesis and parvalbumin positive interneuron loss. Deletion of NKCC1 in astrocytes neither rescued interneurons nor promote neurogenesis. Interestingly, bumetanide had a strong effect on microglial activation by inducing polarization towards the M1-like phenotype 3 days post-CCI and the M2-like phenotype 7 days post-CCI. Bumetanide increased microglial Brain-derived neurotrophic factor (BDNF) expression and interaction with parvalbumin interneurons. The early treatment with bumetanide resulted in improvements in working and episodic memory, one-month post-CCI, as well as the normalization of theta band oscillations. InterpretationHere, we disclose a novel mechanism for the neuroprotective action of bumetanide mediated by an acceleration of microglial activation dynamics that leads to an increase of parvalbumin interneuron survival following CCI, possibly resulting from increased microglial BDNF expression and contact with interneurons. Salvage of interneurons may normalize ambient gamma-aminobutyric acid (GABA) resulting in the preservation of adult neurogenesis processes as well as contributing to bumetanide-mediated improvement of cognitive performance.

neuroscience↗

bioRxiv2022

A Unified Dynamic and Computational Mechanism for Persistent and Transient Neural Activity Patterns During Delayed-Response Tasks

Understanding how the brain preserves information despite intrinsic noise is a fundamental question in working memory. Typical working memory tasks consist of delay phase for maintaining information, and decoding phase for retrieving information. While previous works have focused on the delay neural dynamics, it is poorly understood whether and how the neural process during decoding phase reduces memory error. We studied this question by training recurrent neural networks (RNNs) on a color delayed-response task. We found that the trained RNNs reduce the memory error of high-probability-occurring colors (common colors) by decoding/attributing a broader range of neural states to them during decoding phase. This decoding strategy can be further explained by a continuing converging neural dynamics following delay phase and a non-dynamic biased readout process. Our findings highlight the role of the decoding phase in working memory, suggesting that neural systems deploy multiple strategies across different phases to reduce memory errors. SignificancePreserving information under noise is crucial in working memory. A typical working memory task consists of a delay phase for maintaining information, and a decoding phase for decoding the maintained into an output action. While the delay neural dynamics have been intensively studied, the impact of the decoding phase on memory error reduction remains unexplored. We trained recurrent neural networks (RNNs) on a color delayed-response task and found that RNNs reduce memory error of a color by decoding a larger portion of the neural state to that color. This strategy is supported both by a converging neural dynamic, and a non-dynamic readout process. Our results suggest that neural networks can utilize diverse strategies, beyond delay neural dynamics, to reduce memory errors.

neuroscience↗

bioRxiv2022

A Unified Catalog of 19,251 Non-human Reference Species Genomes Provides New Insights into the Mammalian Gut Microbiomes

The gut microbiota is essential for host health and survival. Here, using samples from animals living in the Qinghai-Tibetan Plateau, we recovered 119,568 metagenome-assembled genomes (MAGs) that were clustered into 19,251 species-level genome bins (SGBs) of which most represent novel species. We present a novel mechanism shaping mammalian gut microbiomes using ancestral founder bacteria (AFB) as a core skeleton and recurring lineage-specific gains of microbial species that are transferred frequently among multiple hosts, not strictly limited by host phylogeny. Such lineage specific gains are responsible for increasing gut microbial diversity, maintaining functional stability, and endowing specific functions for host adaptions. Our analyses did not support the existence of co-phylogeny or co-speciation events between mammal hosts and their individual gut symbionts. The results presented in this study not only reveal novel unique gut microbial species and offer insight of value for understanding the diversity, stability, functionality of the mammalian gut microbiomes, and the co-evolution with their hosts, but also emphasize that animals living in extreme environments are a promising resource for the discovery of novel biological functions.

microbiology↗

bioRxiv2022

Exercise reprograms the inflammatory landscape of multiple stem cell compartments during mammalian aging

Exercise has the ability to rejuvenate stem cells and improve tissue homeostasis and regeneration in aging animals. However, the cellular and molecular changes elicited by exercise have not been systematically studied across a broad range of cell types in stem cell compartments. To gain better insight into the mechanisms by which exercise affects niche and stem cell function, we subjected young and old mice to aerobic exercise and generated a single cell transcriptomic atlas of muscle, neural and hematopoietic stem cells with their niche cells and progeny. Complementarily, we also performed whole transcriptome analysis of single myofibers from these animals. We identified common and unique pathways that are compromised across these tissues and cell types in aged animals. We found that exercise has a rejuvenating effect on subsets of stem cells, and a profound impact in the composition and transcriptomic landscape of both circulating and tissue resident immune cells. Exercise ameliorated the upregulation of a number of inflammatory pathways as well as restored aspects of cell-cell communication within these stem cell compartments. Our study provides a comprehensive view of the coordinated responses of multiple aged stem cells and niche cells to exercise at the transcriptomic level.

cell biology↗

bioRxiv2022

Sub-second striatal dopamine dynamics assessed by simultaneous fast-scan cyclic voltammetry and fluorescence biosensor

Dopamine produces neuromodulation throughout the basal ganglia, cortex and other brain regions, and is implicated in movement control, neural mechanisms of reward and actions of misused substances. The efferent projections of dopaminergic neurons with somata in the substantia nigra pars compacta and ventral tegmental area strongly innervate different striatal subregions. While much is known about the function of these neurons, there is a relative deficiency of information about in vivo dopamine dynamics in the nigrostriatal projections, especially those to the dorsolateral striatum (DLS). In past studies, subsecond dopamine changes were measured predominantly with fast-scan cyclic voltammetry (FSCV) both in brain slices and in vivo. However, traditional FSCV has limitations in discriminating among catecholamines, and cannot be used for simultaneous measurement of both slow and fast/phasic dopamine changes. In addition, FSCV has been most useful for measuring dopamine in the ventral striatum in vivo with less utility for measurement in dorsolateral striatum. The development of genetically encoded dopamine sensors has provided a new approach to measuring slow and fast dopamine dynamics both in brain slices and in vivo, raising the hope of more facile measurement of in vivo dopamine measurements, including in areas where measurement was previously difficult with FSCV. To this end, we first evaluated dLight photometry in brain slices with simultaneous FSCV. We found that both techniques yielded comparable findings. However, differences were noted in responses to dopamine transporter inhibitors, including cocaine. We then used in vivo fiber photometry with dLight to examine responses to cocaine in DLS and compared responses during Pavlovian conditioning in DLS to two other striatal subregions. These experiments show that dopamine increases are readily detectable in DLS and provide new information about dopamine transient kinetics and slowly developing signaling during conditioning. Overall, our findings indicate that dLight photometry is well suited to measuring dopamine dynamics in a striatal region of great interest where such measurements were difficult previously.

neuroscience↗

bioRxiv2021

High-Speed Low-Light In Vivo Two-Photon Voltage Imaging of Large Neuronal Populations

Monitoring spiking activity across large neuronal populations at behaviorally relevant timescales is critical for understanding neural circuit function. Unlike calcium imaging, voltage imaging requires kilohertz sampling rates which reduces fluorescence detection to near shot noise levels. High-photon flux excitation can overcome photon-limited shot noise but photo-bleaching and photo-damage restricts the number and duration of simultaneously imaged neurons. We investigated an alternative approach aimed at low two-photon flux, voltage imaging below the shot noise limit. This framework involved developing: a positive-going voltage indicator with improved spike detection (SpikeyGi); an ultra-fast two-photon microscope for kilohertz frame-rate imaging across a 0.4x0.4mm2 field of view, and; a self-supervised denoising algorithm (DeepVID) for inferring fluorescence from shot-noise limited signals. Through these combined advances, we achieved simultaneous high-speed, deep-tissue imaging of more than one hundred densely-labeled neurons over one hour in awake behaving mice. This demonstrates a scalable approach for voltage imaging across increasing neuronal populations.

neuroscience↗

bioRxiv2021

Structure Insight into Photosystem I Octamer from Cyanobacteria

Diversity of photosystem oligomers is essential to understand how photosynthetic organisms adopted to light conditions. Given by the structural and physiological significance, the assemblies of PSI supercomplex is of great interest in both chloroplast and cyanobacteria recently. In this study, two novel photosystem I supercomplexes were isolated for the first time from the low light incubated culture of filamentous cyanobacterium Anabaena sp. PCC 7120. These complexes were defined as PSI hexamers and octamers through biochemical and biophysical characterization. Their 77K emission spectra indicated that the red forms of chlorophylls seemed not to be affected during oligomerization. By cryo-EM single particle analysis, a near-atomic (7.0 [A]) resolution structure of PSI octamer was resolved, and the molecular assemblies of stable PSI octamer was revealed.

biophysics↗

bioRxiv2021

Multimodal Detection of Dopamine by Sniffer Cells Expressing Genetically Encoded Fluorescence Sensors

Dopamine serves an important role in supporting both locomotor control and higher brain functions such as motivation and learning. Dopaminergic dysfunction is implicated in an equally multidimensional spectrum of neurological and neuropsychiatric diseases. Extracellular dopamine levels are known to be tightly controlled by presynaptic dopamine transporters (DAT), which is also a main target of psychostimulants. Still, detailed data on dopamine dynamics in space and time is needed to fully understand how dopamine signals are encoded and translated into cellular and behavioral responses, and to uncover the pathological effects of dopamine-related diseases. The recently developed genetically encoded fluorescent dopamine sensors enable unprecedented monitoring of dopamine dynamics and have changed the field of in vivo dopamine recording. However, the potential of these sensors to be used for in vitro and ex vivo assays remains unexplored. Here, we demonstrate a generalizable blueprint for making "sniffer" dopamine cells for multimodal detection of dopamine in vitro and ex vivo. We generated sniffer cell lines with inducible expression of six different dopamine sensors and performed a head-to-head comparison of sensor properties to guide users in sensor selection. In proof-of-principle experiments, we show how the sniffer cells can be applied to measure release of endogenous dopamine from cultured neurons and striatal slices, and for determining total dopamine content in striatal tissue. Furthermore, we use the sniffer cells to quantify DAT-mediated dopamine uptake, and AMPH-induced and constitutive dopamine efflux as a radiotracer free, high-throughput alternative to electrochemical- and radiotracer-based assays. Importantly, the sniffer cells framework can readily be applied to other transmitter systems for which the list of genetically encoded fluorescent sensors is rapidly growing.

neuroscience↗

bioRxiv2021

Abnormal Differentiation and Proliferation of Coronary Arterial Endothelium in Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a severe form of single ventricle congenital heart disease characterized by the underdevelopment of the left ventricle. Early serial postmortem examinations revealed high rate of coronary artery abnormalities in HLHS fetal hearts, such as thickened wall, kinking arteries and ventriculo-coronary arterial connection. However, it is unclear if there is an intrinsic defect in the HLHS coronary vessels and what the underlying molecular mechanism is. Here, we profiled both human fetal heart with an underdeveloped left ventricle (ULV) and ECs differentiated from induced pluripotent stem cells (iPSCs) derived from HLHS patients at single cell resolution. CD144+/NPR3-vascular ECs were selected and further classified as venous, arterial and late arterial subclusters. To study the arterial EC phenotype, we specifically generated iPSC-arterial ECs (AECs, CD34+CDH5+CXCR4+NT5E-/low) derived from three HLHS patients and three age-matched healthy controls. Gene ontology analysis revealed that ULV late arterial EC subcluster showed specific defects in endothelial development, proliferation, and Notch signaling compared to control. Consistently, HLHS iPSCs exhibited impaired AEC differentiation shown as the reduced CXCR4+NT5E-/low AEC progenitor population. Mature HLHS iPSC-AECs also exhibited increased G0/G1 cell cycle arrest with decreased expression of cell cycle related genes (e.g., Ki67, CCND1/2). Additionally, NOTCH targeted genes (e.g., DLL4, HEY1, GJA5) were found suppressed in both ULV AECs and HLHS iPSC-AECs compared to control. We also found the HLHS de novo mutation gene KMT2D directly regulated the transcription of NOTCH targeted genes participating in arterial differentiation and cell proliferation, contributing to the HLHS AEC dysfunctionalities. Intriguingly, the treatment of NOTCH ligand JAG1 improved cell proliferation of HLHS AECs and upregulated G1/S transition genes downstream of NOTCH pathway. In summary, our results revealed that KMT2D directly regulated transcription activity of NOTCH signaling, contributing to the poor differentiation and low proliferation of HLHS coronary AECs.

developmental biology↗

bioRxiv2021

Kdm6a Deficiency Restricted to Mouse Hematopoietic Cells Causes an Age- and Sex-dependent Myelodysplastic Syndrome-Like Phenotype

AbstractKdm6a/Utx, a gene on the X chromosome, encodes a histone K27me3 demethylase that has an orthologue on the Y chromosome (Uty)[1]. We previously identified inactivating mutations of Kdm6a in approximately 50% of mouse acute promyelocytic leukemia samples; however, somatic mutations of KDM6A are more rare in human AML samples, ranging in frequency from 2-15% in different series of patients, where their role in pathogenesis is not yet clear. In this study, we show that female Kdm6aflox/flox mice (with allele inactivation initiated by Vav1-Cre in hematopoietic stem and progenitor cells (HSPCs) have a sex-specific phenotype that emerges with aging, with features resembling a myelodysplastic syndrome (MDS). Female Kdm6a-knockout (KO) mice have an age-dependent expansion of their HSPCs with aberrant self-renewal, but they did not differentiate normally into downstream progeny. These mice became mildly anemic and thrombocytopenic, but did not develop overt leukemia, or die from these cytopenias. ChIP-seq and ATAC-seq studies showed only minor changes in H3K27me3, H3K27ac, H3K4me, H3K4me3 and chromatin accessibility between Kdm6a-WT and Kdm6a-KO mice. Utilizing scRNA-seq, Kdm6a loss was linked to the transcriptional repression of genes that mediate hematopoietic cell fate determination. These data demonstrate that Kdm6a plays an important role in normal hematopoiesis, and that its inactivation may contribute to AML pathogenesis by altering the epigenetic state of HSPCs.

genetics↗

bioRxiv2021

A single nucleotide change in the polC DNA polymerase III in Clostridium thermocellum is sufficient to create a hypermutator phenotype

Clostridium thermocellum is a thermophilic, anaerobic, bacterium that natively ferments cellulose to ethanol, and is a candidate for cellulosic biofuel production. Recently, we identified a hypermutator strain of C. thermocellum with a C669Y mutation in the polC gene, which encodes a DNA polymerase III enzyme. Here we reintroduce this mutation using recently-developed CRISPR tools to demonstrate that this mutation is sufficient to recreate the hypermutator phenotype. The resulting strain shows an approximately 30-fold increase in the mutation rate. This mutation appears to function by interfering with metal ion coordination in the PHP domain responsible for proofreading. The ability to selectively increase the mutation rate in C. thermocellum is a useful tool for future directed evolution experiments. ImportanceCellulosic biofuels are a promising approach to decarbonize the heavy duty transportation sector. A longstanding barrier to cost-effective cellulosic biofuel production is the recalcitrance of the material to solubilization. Native cellulose-consuming organisms, such as Clostridium thermocellum, are promising candidates for cellulosic biofuel production, however they often need to be genetically modified to improve product formation. One approach is adaptive laboratory evolution. Our findings demonstrate a way to increase the mutation rate in this industrially-relevant organism, which can reduce the time needed for adaptive evolution experiments.

bioengineering↗

bioRxiv2021

Frequency-specific coactivation patterns in resting-state and their alterations in schizophrenia: an fMRI study

The resting-state human brain is a dynamic system that shows frequency-specific characteristics. Coactivation pattern (CAP) analysis has been recently used to identify recurring brain states sharing similar coactivation configurations. However, whether and how CAPs differ across different sub-frequency bands are unknown. In the current study, in addition to the typical low-frequency range (0.01 - 0.08 Hz), the spatial and temporal characteristics of CAPs in four sub-frequency bands, slow-5 (0.01 - 0.027 Hz), slow-4 (0.027 - 0.073 Hz), slow-3 (0.073 - 0.198 Hz), and slow-2 (0.198 - 0.25 Hz), were studied. Six CAP states were obtained for each band., The CAPs from the typical frequency range were spatially largely overlapped with those in slow-5, slow-4 and slow-3 but not with those in slow-2. With the increase of frequency, the CAP state became more unstable and resulted in an overall shorter persistence. The spatial and temporal characteristics of slow-4 and slow-5 were further compared, because they constitute most power of the resting-state fMRI signals. In general, slow-4 showed stronger coactivations or co-deactivations in subcortical regions, while slow-5 showed stronger coactivations or co-deactivations in large-scale cortical networks such as the dorsal attention network. Lastly, frequency-dependent dynamic alterations were also observed in schizophrenia patients. Combining the information obtained from both slow-5 and slow-4 increased the classification accuracy of schizophrenia patients than only using the typical range. In conclusion, our results revealed that the spatial and temporal characteristics of CAP state varied at different frequency bands, which could be helpful for identifying brain alterations in schizophrenia.

neuroscience↗

bioRxiv2021

Release of endogenous dynorphin opioids in the prefrontal cortex disrupts cognition

Following repeated opioid use, some dependent individuals experience persistent cognitive deficits that contribute to relapse of drug-taking behaviors, and one component of this response may be mediated by the endogenous dynorphin/kappa opioid system in neocortex. In mice, we find that acute morphine withdrawal evokes dynorphin release in the medial prefrontal cortex (PFC) and disrupts cognitive function by activation of local kappa opioid receptors (KORs). Immunohistochemical analyses using a phospho-KOR antibody confirmed that both withdrawal-induced and optically evoked dynorphin release activated KOR in PFC. Using a genetically encoded sensor based on inert KOR (kLight1.2a), we revealed the in vivo dynamics of endogenous dynorphin release in the PFC. Local activation of KOR in PFC produced multi-phasic disruptions of memory processing in an operant delayed alternation behavioral task, which manifest as reductions in response number and accuracy during early and late phases of an operant session. Local pretreatment in PFC with the selective KOR antagonist norbinaltorphimine (norBNI) blocked the disruptive effect of systemic KOR activation during both early and late phases of the session. The early, but not late phase disruption was blocked by viral excision of PFC KORs, suggesting an anatomically dissociable contribution of pre- and postsynaptic KORs. Naloxone-precipitated withdrawal in morphine-dependent mice or optical stimulation of pdynCre neurons using Channelrhodopsin-2 (ChR2) disrupted delayed alternation performance, and the dynorphin-induced effect was blocked by local norBNI. Our findings describe a mechanism for control of cortical function during opioid dependence and suggest that KOR antagonism could promote abstinence.

neuroscience↗