Memories can be altered when they are recalled through the process of reconsolidation, requiring gene expression in brain cells that store these memories. How brain circuits reformat memories during recall by directing m...Memories can be altered when they are recalled through the process of reconsolidation, requiring gene expression in brain cells that store these memories. How brain circuits reformat memories during recall by directing molecular signaling in specific neuronal populations is not known. Here, we show that brainstem noradrenaline projections to the amygdala, a brain region that stores aversive emotional memories, control memory reconsolidation in rats. During reconsolidation, this circuit regulates the nuclear translocation of CREB-regulated transcriptional coactivator-1 (CRTC1), a molecule important for synapse-to-nucleus transcriptional regulation, through β-adrenergic receptor (β-AR) signaling. Cell-type-specific molecular manipulations revealed that reconsolidation requires both β-AR signaling and CRTC1 in an anatomically and genetically defined amygdala cell population. Finally, increasing stress prior to memory recall enhanced reconsolidation, an effect that was mimicked by amygdala cell-type-specific upregulation of noradrenaline signaling. These results reveal a circuit-to-molecular pathway for state-dependent modification of emotional memories during recall.
Recurrent neural networks can generate dynamics, but in the sensory cortex, it has been unclear if any dynamic processing is supported by the dense recurrent excitatory-excitatory network. Here, we show a role for recurr...Recurrent neural networks can generate dynamics, but in the sensory cortex, it has been unclear if any dynamic processing is supported by the dense recurrent excitatory-excitatory network. Here, we show a role for recurrent connections in the mouse visual cortex: they support powerful dynamical computations, but by filtering sequences of input instead of generating sequences. Using two-photon optogenetics, we measure neural responses to natural images and play them back, finding that responses are boosted when inputs are played back during the correct movie dynamic context-when the preceding sequence corresponds to natural vision. This sequence selectivity depends on a network mechanism: earlier input patterns produce responses in other local neurons, which interact with later input patterns. We confirm this mechanism by designing sequences of inputs that are boosted or attenuated by the network. These data suggest that recurrent cortical connections perform predictive processing, encoding the statistics of the natural world in input-output transformations.
Local dendritic computations are thought to critically influence neuronal signaling and plasticity yet remain largely unexplored in vivo due to challenges in stably imaging small structures at ultrafast timescales. We de...Local dendritic computations are thought to critically influence neuronal signaling and plasticity yet remain largely unexplored in vivo due to challenges in stably imaging small structures at ultrafast timescales. We developed a 3D real-time motion correction platform for movement-stabilized, ultrafast two-photon voltage imaging. By co-labeling CA1 pyramidal neurons with voltage and calcium indicators, we simultaneously measured somato-dendritic and electro-calcium coupling at multiple dendritic sites. We characterized isolated dendritic spikes and distance-dependent backpropagation of naturally occurring and photostimulation-evoked bursts and single spikes. We found that bursts backpropagated more reliably than single spikes, validated that somato-dendritic coupling decreases with distance from soma, and showed that electro-calcium coupling decreases with increasing branch order. These findings provide in vivo evidence for distance-dependent invasion of somatic signals into dendrites, highlight the prevalence of isolated dendritic events, and show that dendritic structure isolates voltage from calcium signaling, potentially enabling unique intracellular pathways in distal dendrites.
The development of an adult brain from a single zygote requires cells and axons to organize in precise spatial patterns over long distances. Most mechanisms for positional information rely on diffusible molecular cues th...The development of an adult brain from a single zygote requires cells and axons to organize in precise spatial patterns over long distances. Most mechanisms for positional information rely on diffusible molecular cues that move through the tissue, fundamentally limiting the pattern's ability to scale over the requisite orders of magnitude. Here, we propose a complementary mechanism in which positional information is inherited through the cell lineage, rather than transmitted through extracellular signals, thereby avoiding these scaling constraints. Analyzing brain-wide developmental expression in mouse and larval zebrafish, we find that principal eigengenes-co-expression patterns across thousands of genes-span multiple spatial scales, remain stable over development, and are conserved across species. Moreover, small subsets of genes can decode eigengenes, yielding multi-scale positional information. Together, these findings suggest a lineage-based mechanism for scalable positional information that complements diffusion-based mechanisms and offers a general framework for tissue patterning.
We demonstrate a noninvasive approach for measuring transgene expression in the brains of nonhuman primates using blood-based assays with engineered reporters termed released markers of activity (RMAs). RMAs cross the bl...We demonstrate a noninvasive approach for measuring transgene expression in the brains of nonhuman primates using blood-based assays with engineered reporters termed released markers of activity (RMAs). RMAs cross the blood-brain barrier via reverse transcytosis, allowing detection of brain-derived markers in the bloodstream. Using this approach, we demonstrate repeated monitoring of multiple transgenes expressed in cortical and subcortical regions over several weeks. RMAs are sufficiently sensitive to detect circuit-specific, Cre-dependent adeno-associated viral (AAV) expression, and RMA signals are correlated with histological quantification of gene expression in neural tissue. Together, these findings establish the RMA platform as a cost-efficient and repeatable tool for neuroscience studies in nonhuman primates, enabling sensitive and multiplexed measurement of brain gene expression with a simple blood test.
α-Synuclein conformational strains provide a potential explanation for the clinical and pathological differences among synucleinopathies such as Parkinson's disease and multiple system atrophy. However, how distinct α-sy...α-Synuclein conformational strains provide a potential explanation for the clinical and pathological differences among synucleinopathies such as Parkinson's disease and multiple system atrophy. However, how distinct α-synuclein strains arise remains unknown. Here, we observed conformational heterogeneity between individual preparations of α-synuclein pre-formed fibrils (PFFs) generated by polymerizing wild-type or A53T-mutant human α-synuclein under identical conditions. Moreover, we found that α-synuclein aggregates formed spontaneously in the brains of a transgenic synucleinopathy mouse model are conformationally diverse. Propagation of stochastically formed PFF- and brain-derived α-synuclein strains in mice initiated several distinct synucleinopathies. The conformational diversity of α-synuclein aggregates across PFF preparations and between individual mice demonstrates that α-synuclein can spontaneously form multiple self-propagating strains within an identical environment. This suggests that stochastic misfolding into distinct aggregate structures drives the emergence of α-synuclein strains and reveals that the intrinsic variability of common synucleinopathy research tools must be considered when designing and interpreting experiments.
Jeong M, Baek S, Wang Q
… +14 more, Yao L, Lee EJ, Marroquin Rivera A, Lee JJ, Jang H, Bambah-Mukku D, Mun CH, Boesen T, Nanda S, Ku CR, Dong HW, Labonté B, Paik SB, Lim BK
Drug craving persists after prolonged abstinence, posing a major challenge in treating substance use disorders. The ventral medial prefrontal cortex (vmPFC) plays a critical role in impulsivity and decision-making, makin...Drug craving persists after prolonged abstinence, posing a major challenge in treating substance use disorders. The ventral medial prefrontal cortex (vmPFC) plays a critical role in impulsivity and decision-making, making it a promising target for mitigating drug craving by orchestrating downstream brain-wide activity. However, the dynamics of vmPFC sub-circuits during the progression of drug addiction remain unclear. Here, we uncover a circuit-level mechanism by which distinct vmPFC sub-circuits, defined by cell-type-specific interneurons and projection-specific cortical outputs, differentially modulate mesolimbic pathways to drive drug-seeking behavior. Our results reveal that distinct interneuron subtypes display unique activity dynamics and exert selective modulation over projection-specific cortical outputs. Notably, parvalbumin (PV)-positive interneurons exhibit target-specific synaptic remodeling with pyramidal neurons projecting to distinct downstream targets, which is crucial for modulating mesolimbic circuits and driving persistent cocaine seeking after abstinence. These findings provide compelling insights into vmPFC microcircuit mechanisms underlying substance use disorders.
Microglia-mediated neuroinflammation is increasingly recognized as a key pathological component in autism spectrum disorders (ASDs), though the mechanisms driving microglial activation remain largely elusive. Our study r...Microglia-mediated neuroinflammation is increasingly recognized as a key pathological component in autism spectrum disorders (ASDs), though the mechanisms driving microglial activation remain largely elusive. Our study reveals that deficiency in the high-risk ASD gene SETDB1, as well as maternal immune activation (MIA), elevates complement protein C4b expression specifically in prefrontal cortex (PFC) neurons. This upregulation triggers excessive microglial synaptic pruning, leading to autistic-like behaviors. Furthermore, we found that microglia elimination improved synaptic density, while complete C4b knockout rescued all observed autistic-like phenotypes in mice. C4b expression is driven by RNA-DNA hybrids formed through the reactivation of endogenous retroviruses (ERVs). Notably, we identify that existing FDA-approved HIV medications, which inhibit retrotranscriptional activity, substantially reduce C4b levels and alleviate ASD symptoms. These findings underscore the crucial role of C4b in microglia-mediated synaptic pruning in ASD and highlight the therapeutic potential of targeting ERV reactivation with existing HIV medications.
Yang T, Che T, Guo H
… +22 more, Cheng X, Wang M, Lv S, Yang X, Wu X, Liu Y, Liu H, Hu H, Li W, Wan S, Peng H, Nan W, Zhang Y, Zeng B, Neher E, Liu O, Yu B, Li F, Li G, Li J, Duan J, Zhang J
Current analgesics are limited by insufficient efficacy and adverse effects. TRPM3, a non-opioid target expressed in sensory neurons, represents a promising yet challenging therapeutic avenue due to a lack of potent, sel...Current analgesics are limited by insufficient efficacy and adverse effects. TRPM3, a non-opioid target expressed in sensory neurons, represents a promising yet challenging therapeutic avenue due to a lack of potent, selective antagonists and unresolved structural pharmacology. We determined cryo-electron microscopy (cryo-EM) structures of human TRPM3, identifying a compact ligand-binding pocket that enabled large-scale virtual screening. Structure-based lead optimization yielded a picomolar antagonist with favorable drug-like properties. This compound exhibited potent, dose-dependent analgesia across multiple rodent models of neuropathic and migraine pain. Our work establishes a structure-based discovery pipeline for TRP channels, delivering a high-potency antagonist that validates TRPM3 as a therapeutic target and provides a framework for rational drug design against other ion channels.
More than passive sensory inputs, odors exert proactive influences on homeostasis and cognition. We propose that olfactory signals act as predictive priors for gastric interoception, reframing gut sensations as expectati...More than passive sensory inputs, odors exert proactive influences on homeostasis and cognition. We propose that olfactory signals act as predictive priors for gastric interoception, reframing gut sensations as expectation-driven experiences that actively shape interoceptive inference.
The colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 has been widely used to deplete microglia for functional characterization and therapeutic support. Although diverse outcomes have been described after PL...The colony-stimulating factor 1 receptor (CSF1R) inhibitor PLX5622 has been widely used to deplete microglia for functional characterization and therapeutic support. Although diverse outcomes have been described after PLX5622 treatment, whether these phenotypes solely reflect microglial functions remains to be determined. Here, we show that transgenic microglial depletion did not mimic the accelerated anesthetic arousal or the alleviated nicotine addiction withdrawal symptoms observed after PLX5622 treatment in mice. We further identify that PLX5622 potently activates the mouse constitutive androstane receptor (CAR), leading to prominent induction of hepatic enzymes. The induced enzymatic activity enhances the metabolism and clearance of anesthetics and nicotine, thereby contributing to anesthetic insensitivity and addiction relief. Inactivation of CAR abolished these effects of PLX5622, indicating that the impact of PLX5622 treatment cannot be attributed exclusively to microglial depletion. Our findings raise awareness in evaluating consequences of PLX5622 treatment and provide insights into the design of specific CSF1R inhibitors.
Understanding how behavior modulates neuronal integration is a fundamental goal in neuroscience. We combined voltage imaging with optogenetics to reveal how excitatory (E) and inhibitory (I) inputs modulate spiking outpu...Understanding how behavior modulates neuronal integration is a fundamental goal in neuroscience. We combined voltage imaging with optogenetics to reveal how excitatory (E) and inhibitory (I) inputs modulate spiking output, subthreshold dynamics, and gain in genetically defined CA1 neurons. We imaged pyramidal cells (PCs), vasoactive intestinal peptide (VIP), somatostatin (SST), and parvalbumin (PV) interneurons (INs) and found that locomotion reduced firing in PCs and VIP INs while increasing activity in SST and PV INs. Prolonged optical depolarization revealed that inhibitory inputs substantially contribute to intracellular theta oscillations in PCs and VIP cells. Firing rate-laser intensity (F-I) curves revealed distinct gain modulation across cell types, with a divisive gain reduction in PC bursting during locomotion, while simple spikes are unaffected. A two-compartment model suggested that this effect results from a balanced increase in E/I input to the soma and dendrite. These findings reveal how behavior coordinates E/I signaling to modulate hippocampal computations.
Feeding behavior is tightly regulated by circadian rhythms, and disruption of this coordination promotes mistimed eating and metabolic dysfunction. Here, using mouse models, we identify a noncanonical role of neuropeptid...Feeding behavior is tightly regulated by circadian rhythms, and disruption of this coordination promotes mistimed eating and metabolic dysfunction. Here, using mouse models, we identify a noncanonical role of neuropeptide Y-expressing interneurons (NPY-INs) in the ventral hippocampus (vHPC) in circadian feeding control. vHPC NPY-INs exhibit robust diurnal activity fluctuations that are lost under chronic circadian disruption. Functionally, these neurons regulate feeding across the day-night cycle by engaging distinct transmitters: NPY signaling predominates during the light phase, whereas gamma-aminobutyric acid (GABA) signaling dominates during the dark phase. Furthermore, vHPC NPY-INs receive monosynaptic glutamatergic and GABAergic inputs from the medial preoptic area (MPOA), which confer circadian plasticity, and project to the ventral subiculum (vSub), where NPYR and NPYR signaling mediates feeding behavior. Together, these findings identify the vHPC NPY-INs as a critical hub linking circadian regulation and energy balance, offering new insight into neural mechanisms underlying mistimed feeding and metabolic disorders.
Parallel visual processing begins with retinal bipolar cells, traditionally regarded as independent chemical synaptic channels. However, the circuit-level synaptic integration of chemical and electrical synapses within t...Parallel visual processing begins with retinal bipolar cells, traditionally regarded as independent chemical synaptic channels. However, the circuit-level synaptic integration of chemical and electrical synapses within this network remains unclear. Using dual patch-clamp recordings and two-photon imaging in whole-mount retina, we systematically characterized synaptic transmission across 13 mouse and 2 human cone bipolar cell (CBC) types, revealing two distinct modes: a fast, direct chemical pathway and a slower, serial electrical-chemical circuit among both ON and OFF CBCs. In mice, the slow mode generates spatially dispersed glutamate "clouds" that facilitate integration across CBC types. We discovered specific "driver" CBCs that distribute robust, sustained signals through a hierarchical, functionally rectified network, enhancing sensitivity to small, low-contrast stimuli in downstream retinal cells and thalamic neurons in awake mice. Our findings challenge the classical view of independent CBC channels, revealing an integrative, hierarchical electrical-chemical synaptic architecture that enhances visual detection and coding efficiency.
The suprachiasmatic nucleus (SCN) is considered the master pacemaker of the circadian clock in mammals, but our current knowledge of the SCN is mostly based on rodent studies. Here, we report a comprehensive molecular an...The suprachiasmatic nucleus (SCN) is considered the master pacemaker of the circadian clock in mammals, but our current knowledge of the SCN is mostly based on rodent studies. Here, we report a comprehensive molecular and cellular atlas for the adult human SCN by spatial transcriptomics, single-nucleus RNA sequencing, and deep-learning-based histological analysis. We identified seven human SCN neuron subtypes with specific transcriptomes and spatial distributions. Comparison of humans, mice, and non-human primates revealed the conserved functional segregation within the SCN regulated by LIM homeobox 1 (LHX1) and RAR-related orphan receptor B (RORB). Furthermore, our results suggested that the human SCN has undergone marked reorganization of its neuropeptide signaling network. Finally, integrative analysis of human SCN transcriptomes and genome-wide association studies (GWASs) identified arginine vasopressin (AVP)/neuromedin S (NMS) subtype as the potential neuronal correlate for morningness chronotype. Thus, our spatial and single-cell transcriptomic atlas of the human SCN provided a basis for the understanding of neural and molecular mechanisms of the human circadian clock.
Synapse formation and elimination are two crucial processes that occur concurrently in the developing brain. Astrocytes and microglia control both processes, yet how these two major glial cell types of the central nervou...Synapse formation and elimination are two crucial processes that occur concurrently in the developing brain. Astrocytes and microglia control both processes, yet how these two major glial cell types of the central nervous system (CNS) communicate to balance synapse formation and elimination is unknown. Astrocytes secrete the synaptogenic protein Hevin/SPARCL1, which induces the formation and plasticity of thalamocortical synapses in the mouse visual cortex. Here, we found that, in addition to this synaptogenic function, Hevin directly signals to microglia by interacting with Toll-like receptor 4 (TLR4). This signaling occurs when Hevin is proteolytically cleaved, producing a C-terminal fragment that is no longer synaptogenic. We found that Hevin, through TLR4, induces a distinct microglial state defined by increased TLR2 expression and phago-lysosomal content in vitro and in vivo. Microglial TLR4 signaling is required for the proper elimination of thalamocortical synapses during early postnatal development.
Neuronal firing patterns have significant spatiotemporal variability with no agreed-upon theoretical framework. Using a combined experimental and modeling approach, we found that spike interval statistics of excitatory n...Neuronal firing patterns have significant spatiotemporal variability with no agreed-upon theoretical framework. Using a combined experimental and modeling approach, we found that spike interval statistics of excitatory neurons in the mammalian forebrain are dominated by a universal low-rate ("ground state"; GS) mode, with irregular spiking at neuron-specific rates. In contrast, when firing rates are increased during intrinsic network patterns or in response to stimuli, spiking across neurons is temporally coordinated with more regular spiking patterns in a region- and brain-state-specific manner. We demonstrate the generality of this distinction in six forebrain areas and show that the majority of spikes in all regions are emitted in the GS mode, emphasizing its physiological importance. We hypothesize that GS spiking maintains persistent neuronal dynamics.
To pursue a moving visual object, the brain must continuously steer the object to the center of the visual field via feedback. The gain of this control loop is flexible, yet the biological mechanisms underlying such adap...To pursue a moving visual object, the brain must continuously steer the object to the center of the visual field via feedback. The gain of this control loop is flexible, yet the biological mechanisms underlying such adaptive control are not well understood. Here, we show that adaptive control in the Drosophila pursuit system involves two parallel pathways. One detects objects in the periphery and steers them toward the center of the visual field. The other detects objects near the center of the visual field and steers them to the visual midline while also increasing forward velocity. This latter pathway is flexible: gain increases when the object is moving away from the midline and when the pursuer is running fast-situations that demand rapid steering-and this pathway is preferentially recruited during arousal. Our findings demonstrate how adaptive control can emerge from parallel sensory-motor pathways with specialized properties.
Recent advances in three-dimensional single-cell-resolution imaging have begun to link organ-wide and cellular-level research in development and disease. Although powerful, whole-organ imaging remains limited by the inab...Recent advances in three-dimensional single-cell-resolution imaging have begun to link organ-wide and cellular-level research in development and disease. Although powerful, whole-organ imaging remains limited by the inability to stain a broad range of molecular markers and by the lack of an analytical scheme to precisely quantify cell populations. Here, we present a highly multiplexed whole-mount staining technique, utilizing the repeated application of fluorescence in situ hybridization. This technique, termed mFISH3D, enables the visualization of 10 types of mRNAs in an intact mouse brain and has been demonstrated in various biological specimens, including the human brain. To achieve higher levels of accuracy in spatial cell mapping, we developed an artificial intelligence (AI)-driven workflow that reduces the need for extensive manual annotations. This integration provides a systematic framework for analyzing complex cellular ecosystems across large tissue volumes and enables the comprehensive investigation of selective cellular vulnerabilities in disease.
In this issue of Neuron, Papadopoulos et al. demonstrate that stimulus encoding accuracy in auditory cortex rises and then falls with increasing arousal. Their model of stimulus-induced transitions between discrete, arou...In this issue of Neuron, Papadopoulos et al. demonstrate that stimulus encoding accuracy in auditory cortex rises and then falls with increasing arousal. Their model of stimulus-induced transitions between discrete, arousal-dependent attractor states of spiking neurons successfully accounts for their data.