a Transcriptomic Correlates of State Modulation in GABAergic Interneurons: A Cross-Species Analysis By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 GABAergic inhibitory interneurons comprise many subtypes that differ in their molecular, anatomical, and functional properties. In mouse visual cortex, they also differ in their modulation with an animal’s behavioral state, and this state modulation can be predicted from the first principal component (PC) of the gene expression matrix. Here, we ask whether this link between transcriptome and state-dependent processing generalizes across species. To this end, we analysed seven single-cell and single-nucleus RNA sequencing datasets from mouse, human, songbird, and turtle forebrains. Despite homology at the level of cell types, we found clear differences between transcriptomic PCs, with greater dissimilarities between evolutionarily distant species. These dissimilarities arise from two factors: divergence in gene expression within homologous cell types and divergence in cell-type abundance. We also compare the expression of cholinergic receptors, which are thought to causally link transcriptome and state modulation. Several cholinergic receptors predictive of state modulation in mouse interneurons are differentially expressed between species. Circuit modelling and mathematical analyses suggest conditions under which these expression differences could translate into functional differences. Full Article
a Our Brains on Art: An Ancient Prescription for 21st Century Solutions By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Full Article
a A miR-383-5p Signaling Hub Coordinates the Axon Regeneration Response to Inflammation By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Neuroinflammation can positively influence axon regeneration following injury in the central nervous system. Inflammation promotes the release of neurotrophic molecules and stimulates intrinsic proregenerative molecular machinery in neurons, but the detailed mechanisms driving this effect are not fully understood. We evaluated how microRNAs are regulated in retinal neurons in response to intraocular inflammation to identify their potential role in axon regeneration. We found that miR-383-5p is downregulated in retinal ganglion cells in response to zymosan-induced intraocular inflammation. MiR-383-5p downregulation in neurons is sufficient to promote axon growth in vitro, and the intravitreal injection of a miR-383-5p inhibitor into the eye promotes axon regeneration following optic nerve crush. MiR-383-5p directly targets ciliary neurotrophic factor (CNTF) receptor components, and miR-383-5p inhibition sensitizes adult retinal neurons to the outgrowth-promoting effects of CNTF. Interestingly, we also demonstrate that CNTF treatment is sufficient to reduce miR-383-5p levels in neurons, constituting a positive-feedback module, whereby initial CNTF treatment reduces miR-383-5p levels, which then disinhibits CNTF receptor components to sensitize neurons to the ligand. Additionally, miR-383-5p inhibition derepresses the mitochondrial antioxidant protein peroxiredoxin-3 (PRDX3) which was required for the proregenerative effects associated with miR-383-5p loss-of-function in vitro. We have thus identified a positive-feedback mechanism that facilitates neuronal CNTF sensitivity in neurons and a new molecular signaling module that promotes inflammation-induced axon regeneration. Full Article
a The Critical Thing about the Ear's Sensory Hair Cells By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 The capabilities of the human ear are remarkable. We can normally detect acoustic stimuli down to a threshold sound-pressure level of 0 dB (decibels) at the entrance to the external ear, which elicits eardrum vibrations in the picometer range. From this threshold up to the onset of pain, 120 dB, our ears can encompass sounds that differ in power by a trillionfold. The comprehension of speech and enjoyment of music result from our ability to distinguish between tones that differ in frequency by only 0.2%. All these capabilities vanish upon damage to the ear's receptors, the mechanoreceptive sensory hair cells. Each cochlea, the auditory organ of the inner ear, contains some 16,000 such cells that are frequency-tuned between ~20 Hz (cycles per second) and 20,000 Hz. Remarkably enough, hair cells do not simply capture sound energy: they can also exhibit an active process whereby sound signals are amplified, tuned, and scaled. This article describes the active process in detail and offers evidence that its striking features emerge from the operation of hair cells on the brink of an oscillatory instability—one example of the critical phenomena that are widespread in physics. Full Article
a Dopamine and Norepinephrine Differentially Mediate the Exploration-Exploitation Tradeoff By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Dopamine (DA) and norepinephrine (NE) have been repeatedly implicated in neuropsychiatric vulnerability, in part via their roles in mediating the decision-making processes. Although two neuromodulators share a synthesis pathway and are coactivated under states of arousal, they engage in distinct circuits and modulatory roles. However, the specific role of each neuromodulator in decision-making, in particular the exploration–exploitation tradeoff, remains unclear. Revealing how each neuromodulator contributes to exploration–exploitation tradeoff is important in guiding mechanistic hypotheses emerging from computational psychiatric approaches. To understand the differences and overlaps of the roles of these two catecholamine systems in regulating exploration, a direct comparison using the same dynamic decision-making task is needed. Here, we ran male and female mice in a restless two-armed bandit task, which encourages both exploration and exploitation. We systemically administered a nonselective DA antagonist (flupenthixol), a nonselective DA agonist (apomorphine), a NE beta-receptor antagonist (propranolol), and a NE beta-receptor agonist (isoproterenol) and examined changes in exploration within subjects across sessions. We found a bidirectional modulatory effect of dopamine on exploration. Increasing dopamine activity decreased exploration and decreasing dopamine activity increased exploration. The modulatory effect of beta-noradrenergic receptor activity on exploration was mediated by sex. Reinforcement learning model parameters suggested that dopamine modulation affected exploration via decision noise and norepinephrine modulation affected exploration via sensitivity to outcome. Together, these findings suggested that the mechanisms that govern the exploration–exploitation transition are sensitive to changes in both catecholamine functions and revealed differential roles for NE and DA in mediating exploration. Full Article
a Retinal Input to Macaque Superior Colliculus Derives from Branching Axons Projecting to the Lateral Geniculate Nucleus By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 The superior colliculus receives a direct projection from retinal ganglion cells. In primates, it remains unknown if the same ganglion cells also supply the lateral geniculate nucleus. To address this issue, a double-label experiment was performed in two male macaques. The animals fixated a target while injection sites were scouted in the superior colliculus by recording and stimulating with a tetrode. Once suitable sites were identified, cholera toxin subunit B-Alexa Fluor 488 was injected via an adjacent micropipette. In a subsequent acute experiment, cholera toxin subunit B-Alexa Fluor 555 was injected into the lateral geniculate nucleus at matching retinotopic locations. After a brief survival period, ganglion cells were examined in retinal flatmounts. The percentage of double-labeled cells varied locally, depending on the relative efficiency of retrograde transport by each tracer and the precision of retinotopic overlap of injection sites in each target nucleus. In counting boxes with extensive overlap, 76–98% of ganglion cells projecting to the superior colliculus were double labeled. Cells projecting to the superior colliculus constituted 4.0–6.7% of the labeled ganglion cell population. In one particularly large zone, there were 5,746 cells labeled only by CTB-AF555, 561cells double labeled by CTB-AF555 and CTB-AF488, but no cell labeled only by CTB-AF488. These data indicate that retinal input to the macaque superior colliculus arises from a collateral axonal branch supplied by ~5% of the ganglion cells that project to the lateral geniculate nucleus. Surprisingly, there exist no ganglion cells that project exclusively to the SC. Full Article
a Neurophysiology of Effortful Listening: Decoupling Motivational Modulation from Task Demands By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 In demanding listening situations, a listener's motivational state may affect their cognitive investment. Here, we aim to delineate how domain-specific sensory processing, domain-general neural alpha power, and pupil size as a proxy for cognitive investment encode influences of motivational state under demanding listening. Participants (male and female) performed an auditory gap-detection task while the pupil size and the magnetoencephalogram were simultaneously recorded. Task demand and a listener's motivational state were orthogonally manipulated through changes in gap duration and monetary-reward prospect, respectively. Whereas task difficulty impaired performance, reward prospect enhanced it. The pupil size reliably indicated the modulatory impact of an individual's motivational state. At the neural level, the motivational state did not affect auditory sensory processing directly but impacted attentional postprocessing of an auditory event as reflected in the late evoked-response field and alpha-power change. Both pregap pupil dilation and higher parietal alpha power predicted better performance at the single-trial level. The current data support a framework wherein the motivational state acts as an attentional top–down neural means of postprocessing the auditory input in challenging listening situations. Full Article
a Cortically Disparate Visual Features Evoke Content-Independent Load Signals during Storage in Working Memory By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 It is well established that holding information in working memory (WM) elicits sustained stimulus-specific patterns of neural activity. Nevertheless, here we provide evidence for a distinct class of neural activity that tracks the number of individuated items in working memory, independent of the type of visual features stored. We present two EEG studies of young adults of both sexes that provide robust evidence for a signal tracking the number of individuated representations in working memory, regardless of the specific feature values stored. In Study 1, subjects maintained either colors or orientations across separate blocks in a single session. We found near-perfect generalization of the load signal between these two conditions, despite being able to simultaneously decode which feature had been voluntarily stored. In Study 2, participants attended to two features with very distinct cortical representations: color and motion coherence. We again found evidence for a neural load signal that robustly generalized across these distinct visual features, even though cortically disparate regions process color and motion coherence. Moreover, representational similarity analysis provided converging evidence for a content-independent load signal, while simultaneously showing that unique variance in EEG activity tracked the specific features that were stored. We posit that this load signal reflects a content-independent "pointer" operation that binds objects to the current context while parallel but distinct neural signals represent the features that are stored for each item in memory. Full Article
a Differential Encoding of Two-Tone Harmonics in the Male and Female Mouse Auditory Cortex By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Harmonics are an integral part of music, speech, and vocalizations of animals. Since the rest of the auditory environment is primarily made up of nonharmonic sounds, the auditory system needs to perceptually separate the above two kinds of sounds. In mice, harmonics, generally with two-tone components (two-tone harmonic complexes, TTHCs), form an important component of vocal communication. Communication by pups during isolation from the mother and by adult males during courtship elicits typical behaviors in female mice—dams and adult courting females, respectively. Our study shows that the processing of TTHC is specialized in mice providing neural basis for perceptual differences between tones and TTHCs and also nonharmonic sounds. Investigation of responses in the primary auditory cortex (Au1) from in vivo extracellular recordings and two-photon Ca2+ imaging of excitatory and inhibitory neurons to TTHCs exhibit enhancement, suppression, or no-effect with respect to tones. Irrespective of neuron type, harmonic enhancement is maximized, and suppression is minimized when the fundamental frequencies (F0) match the neuron's best fundamental frequency (BF0). Sex-specific processing of TTHC is evident from differences in the distributions of neurons’ best frequency (BF) and best fundamental frequency (BF0) in single units, differences in harmonic suppressed cases re-BF0, independent of neuron types, and from pairwise noise correlations among excitatory and parvalbumin inhibitory interneurons. Furthermore, TTHCs elicit a higher response compared with two-tone nonharmonics in females, but not in males. Thus, our study shows specialized neural processing of TTHCs over tones and nonharmonics, highlighting local network specialization among different neuronal types. Full Article
a Anterior Olfactory Cortices Differentially Transform Bottom-Up Odor Signals to Produce Inverse Top-Down Outputs By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Odor information arrives first in the main olfactory bulb and is then broadcasted to the olfactory cortices and striatum. Downstream regions have unique cellular and connectivity architectures that may generate different coding patterns to the same odors. To reveal region-specific response features, tuning and decoding of single-unit populations, we recorded responses to the same odors under the same conditions across regions, namely, the main olfactory bulb (MOB), the anterior olfactory nucleus (AON), the anterior piriform cortex (aPC), and the olfactory tubercle of the ventral striatum (OT), of awake male mice. We focused on chemically closely related aldehydes that still create distinct percepts. The MOB had the highest decoding accuracy for aldehydes and was the only region encoding chemical similarity. The MOB had the highest fraction of inhibited responses and narrowly tuned odor-excited responses in terms of timing and odor selectivity. Downstream, the interconnected AON and aPC differed in their response patterns to the same stimuli. While odor-excited responses dominated the AON, the aPC had a comparably high fraction of odor-inhibited responses. Both cortices share a main output target that is the MOB. This prompted us to test if the two regions convey also different net outputs. Aldehydes activated AON terminals in the MOB as a bulk signal but inhibited those from the aPC. The differential cortical projection responses generalized to complex odors. In summary, olfactory regions reveal specialized features in their encoding with AON and aPC differing in their local computations, thereby generating inverse net centrifugal and intercortical outputs. Full Article
a Neurons Underlying Aggression-Like Actions That Are Shared by Both Males and Females in Drosophila By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Aggression involves both sexually monomorphic and dimorphic actions. How the brain implements these two types of actions is poorly understood. We found that in Drosophila melanogaster, a set of neurons, which we call CL062, previously shown to mediate male aggression also mediate female aggression. These neurons elicit aggression acutely and without the presence of a target. Although the same set of actions is elicited in males and females, the overall behavior is sexually dimorphic. The CL062 neurons do not express fruitless, a gene required for sexual dimorphism in flies, and expressed by most other neurons important for controlling fly aggression. Connectomic analysis in a female electron microscopy dataset suggests that these neurons have limited connections with fruitless expressing neurons that have been shown to be important for aggression and signal to different descending neurons. Thus, CL062 is part of a monomorphic circuit for aggression that functions parallel to the known dimorphic circuits. Full Article
a This Week in The Journal By www.jneurosci.org Published On :: 2024-10-30T09:30:22-07:00 Full Article
a The Effect of Congruent versus Incongruent Distractor Positioning on Electrophysiological Signals during Perceptual Decision-Making By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Key event-related potentials (ERPs) of perceptual decision-making such as centroparietal positivity (CPP) elucidate how evidence is accumulated toward a given choice. Furthermore, this accumulation can be impacted by visual target selection signals such as the N2 contralateral (N2c). How these underlying neural mechanisms of perceptual decision-making are influenced by the spatial congruence of distractors relative to target stimuli remains unclear. Here, we used electroencephalography (EEG) in humans of both sexes to investigate the effect of distractor spatial congruency (same vs different hemifield relative to targets) on perceptual decision-making. We confirmed that responses for perceptual decisions were slower for spatially incongruent versus congruent distractors of high salience. Similarly, markers of target selection (N2c peak amplitude) and evidence accumulation (CPP slope) were found to be lower when distractors were spatially incongruent versus congruent. To evaluate the effects of congruency further, we applied drift diffusion modeling to participant responses, which showed that larger amplitudes of both ERPs were correlated with shorter nondecision times when considering the effect of congruency. The modeling also suggested that congruency's effect on behavior occurred prior to and during evidence accumulation when considering the effects of the N2c peak and CPP slope. These findings point to spatially incongruent distractors, relative to congruent distractors, influencing decisions as early as the initial sensory processing phase and then continuing to exert an effect as evidence is accumulated throughout the decision-making process. Overall, our findings highlight how key electrophysiological signals of perceptual decision-making are influenced by the spatial congruence of target and distractor. Full Article
a Erratum: McCosh et al., "Norepinephrine Neurons in the Nucleus of the Solitary Tract Suppress Luteinizing Hormone Secretion in Female Mice" By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Full Article
a The Hippocampus Preorders Movements for Skilled Action Sequences By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Plasticity in the subcortical motor basal ganglia–thalamo–cerebellar network plays a key role in the acquisition and control of long-term memory for new procedural skills, from the formation of population trajectories controlling trained motor skills in the striatum to the adaptation of sensorimotor maps in the cerebellum. However, recent findings demonstrate the involvement of a wider cortical and subcortical brain network in the consolidation and control of well-trained actions, including a brain region traditionally associated with declarative memory—the hippocampus. Here, we probe which role these subcortical areas play in skilled motor sequence control, from sequence feature selection during planning to their integration during sequence execution. An fMRI dataset (N = 24; 14 females) collected after participants learnt to produce four finger press sequences entirely from memory with high movement and timing accuracy over several days was examined for both changes in BOLD activity and their informational content in subcortical regions of interest. Although there was a widespread activity increase in effector-related striatal, thalamic, and cerebellar regions, in particular during sequence execution, the associated activity did not contain information on the motor sequence identity. In contrast, hippocampal activity increased during planning and predicted the order of the upcoming sequence of movements. Our findings suggest that the hippocampus preorders movements for skilled action sequences, thus contributing to the higher-order control of skilled movements that require flexible retrieval. These findings challenge the traditional taxonomy of episodic and procedural memory and carry implications for the rehabilitation of individuals with neurodegenerative disorders. Full Article
a Spatiotemporal Neural Network for Sublexical Information Processing: An Intracranial SEEG Study By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Words offer a unique opportunity to separate the processing mechanisms of object subcomponents from those of the whole object, because the phonological or semantic information provided by the word subcomponents (i.e., sublexical information) can conflict with that provided by the whole word (i.e., lexical information). Previous studies have revealed some of the specific brain regions and temporal information involved in sublexical information processing. However, a comprehensive spatiotemporal neural network for sublexical processing remains to be fully elucidated due to the low temporal or spatial resolutions of previous neuroimaging studies. In this study, we recorded stereoelectroencephalography signals with high spatial and temporal resolutions from a large sample of 39 epilepsy patients (both sexes) during a Chinese character oral reading task. We explored the activated brain regions and their connectivity related to three sublexical effects: phonological regularity (whether the whole character's pronunciation aligns with its phonetic radical), phonological consistency (whether characters with the same phonetic radical share the same pronunciation), and semantic transparency (whether the whole character's meaning aligns with its semantic radical). The results revealed that sublexical effects existed in the inferior frontal gyrus, precentral and postcentral gyri, temporal lobe, and middle occipital gyrus. Additionally, connectivity from the middle occipital gyrus to the postcentral gyrus and from postcentral gyrus to the fusiform gyrus was associated with the sublexical effects. These findings provide valuable insights into the spatiotemporal dynamics of sublexical processing and object recognition in the brain. Full Article
a G-Protein Signaling in Alzheimer's Disease: Spatial Expression Validation of Semi-supervised Deep Learning-Based Computational Framework By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Systemic study of pathogenic pathways and interrelationships underlying genes associated with Alzheimer's disease (AD) facilitates the identification of new targets for effective treatments. Recently available large-scale multiomics datasets provide opportunities to use computational approaches for such studies. Here, we devised a novel disease gene identification (digID) computational framework that consists of a semi-supervised deep learning classifier to predict AD-associated genes and a protein–protein interaction (PPI) network-based analysis to prioritize the importance of these predicted genes in AD. digID predicted 1,529 AD-associated genes and revealed potentially new AD molecular mechanisms and therapeutic targets including GNAI1 and GNB1, two G-protein subunits that regulate cell signaling, and KNG1, an upstream modulator of CDC42 small G-protein signaling and mediator of inflammation and candidate coregulator of amyloid precursor protein (APP). Analysis of mRNA expression validated their dysregulation in AD brains but further revealed the significant spatial patterns in different brain regions as well as among different subregions of the frontal cortex and hippocampi. Super-resolution STochastic Optical Reconstruction Microscopy (STORM) further demonstrated their subcellular colocalization and molecular interactions with APP in a transgenic mouse model of both sexes with AD-like mutations. These studies support the predictions made by digID while highlighting the importance of concurrent biological validation of computationally identified gene clusters as potential new AD therapeutic targets. Full Article
a Selective Vulnerability of GABAergic Inhibitory Interneurons to Bilirubin Neurotoxicity in the Neonatal Brain By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Hyperbilirubinemia (HB) is a key risk factor for hearing loss in neonates, particularly premature infants. Here, we report that bilirubin (BIL)-dependent cell death in the auditory brainstem of neonatal mice of both sexes is significantly attenuated by ZD7288, a blocker for hyperpolarization-activated cyclic nucleotide-gated (HCN) channel-mediated current (Ih), or by genetic deletion of HCN1. GABAergic inhibitory interneurons predominantly express HCN1, on which BIL selectively acts to increase their intrinsic excitability and mortality by enhancing HCN1 activity and Ca2+-dependent membrane targeting. Chronic BIL elevation in neonatal mice in vivo increases the fraction of spontaneously active interneurons and their firing frequency, Ih, and death, compromising audition at the young adult stage in HCN1+/+, but not in HCN1–/– genotype. We conclude that HB preferentially targets HCN1 to injure inhibitory interneurons, fueling a feedforward loop in which lessening inhibition cascades hyperexcitability, Ca2+ overload, neuronal death, and auditory impairments. These findings rationalize HCN1 as a potential target for managing HB encephalopathy. Full Article
a A Novel Directed Seed-Based Connectivity Analysis Toolbox Applied to Human and Marmoset Resting-State FMRI By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Estimating the direction of functional connectivity (FC) can help further elucidate complex brain function. However, the estimation of directed FC at the voxel level in fMRI data, and evaluating its performance, has yet to be done. We therefore developed a novel directed seed-based connectivity analysis (SCA) method based on normalized pairwise Granger causality that provides greater detail and accuracy over ROI-based methods. We evaluated its performance against 145 cortical retrograde tracer injections in male and female marmosets that were used as ground truth cellular connectivity on a voxel-by-voxel basis. The receiver operating characteristic (ROC) curve was calculated for each injection, and we achieved area under the ROC curve of 0.95 for undirected and 0.942 for directed SCA in the case of high cell count threshold. This indicates that SCA can reliably estimate the strong cellular connections between voxels in fMRI data. We then used our directed SCA method to analyze the human default mode network (DMN) and found that dlPFC (dorsolateral prefrontal cortex) and temporal lobe were separated from other DMN regions, forming part of the language-network that works together with the core DMN regions. We also found that the cerebellum (Crus I-II) was strongly targeted by the posterior parietal cortices and dlPFC, but reciprocal connections were not observed. Thus, the cerebellum may not be a part of, but instead a target of, the DMN and language-network. Summarily, our novel directed SCA method, visualized with a new functional flat mapping technique, opens a new paradigm for whole-brain functional analysis. Full Article
a Neural Representations of Concreteness and Concrete Concepts Are Specific to the Individual By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Different people listening to the same story may converge upon a largely shared interpretation while still developing idiosyncratic experiences atop that shared foundation. What linguistic properties support this individualized experience of natural language? Here, we investigate how the "concrete–abstract" axis—the extent to which a word is grounded in sensory experience—relates to within- and across-subject variability in the neural representations of language. Leveraging a dataset of human participants of both sexes who each listened to four auditory stories while undergoing functional magnetic resonance imaging, we demonstrate that neural representations of "concreteness" are both reliable across stories and relatively unique to individuals, while neural representations of "abstractness" are variable both within individuals and across the population. Using natural language processing tools, we show that concrete words exhibit similar neural representations despite spanning larger distances within a high-dimensional semantic space, which potentially reflects an underlying representational signature of sensory experience—namely, imageability—shared by concrete words but absent from abstract words. Our findings situate the concrete–abstract axis as a core dimension that supports both shared and individualized representations of natural language. Full Article
a Glucocorticoids Rapidly Modulate CaV1.2-Mediated Calcium Signals through Kv2.1 Channel Clusters in Hippocampal Neurons By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 The precise regulation of Ca2+ signals plays a crucial role in the physiological functions of neurons. Here, we investigated the rapid effect of glucocorticoids on Ca2+ signals in cultured hippocampal neurons from both female and male rats. In cultured hippocampal neurons, glucocorticoids inhibited the spontaneous somatic Ca2+ spikes generated by Kv2.1-organized Ca2+ microdomains. Furthermore, glucocorticoids rapidly reduced the cell surface expressions of Kv2.1 and CaV1.2 channels in hippocampal neurons. In HEK293 cells transfected with Kv2.1 alone, glucocorticoids significantly reduced the surface expression of Kv2.1 with little effect on K+ currents. In HEK293 cells transfected with CaV1.2 alone, glucocorticoids inhibited CaV1.2 currents but had no effect on the cell surface expression of CaV1.2. Notably, in the presence of wild-type Kv2.1, glucocorticoids caused a decrease in the surface expression of CaV1.2 channels in HEK293 cells. However, this effect was not observed in the presence of nonclustering Kv2.1S586A mutant channels. Live-cell imaging showed that glucocorticoids rapidly decreased Kv2.1 clusters on the plasma membrane. Correspondingly, Western blot results indicated a significant increase in the cytoplasmic level of Kv2.1, suggesting the endocytosis of Kv2.1 clusters. Glucocorticoids rapidly decreased the intracellular cAMP concentration and the phosphorylation level of PKA in hippocampal neurons. The PKA inhibitor H89 mimicked the effect of glucocorticoids on Kv2.1, while the PKA agonist forskolin abrogated the effect. In conclusion, glucocorticoids rapidly suppress CaV1.2-mediated Ca2+ signals in hippocampal neurons by promoting the endocytosis of Kv2.1 channel clusters through reducing PKA activity. Full Article
a EphB2 Signaling Is Implicated in Astrocyte-Mediated Parvalbumin Inhibitory Synapse Development By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Impaired inhibitory synapse development is suggested to drive neuronal hyperactivity in autism spectrum disorders (ASD) and epilepsy. We propose a novel mechanism by which astrocytes control the development of parvalbumin (PV)-specific inhibitory synapses in the hippocampus, implicating ephrin-B/EphB signaling. Here, we utilize genetic approaches to assess functional and structural connectivity between PV and pyramidal cells (PCs) through whole-cell patch–clamp electrophysiology, optogenetics, immunohistochemical analysis, and behaviors in male and female mice. While inhibitory synapse development is adversely affected by PV-specific expression of EphB2, a strong candidate ASD risk gene, astrocytic ephrin-B1 facilitates PV->PC connectivity through a mechanism involving EphB signaling in PV boutons. In contrast, the loss of astrocytic ephrin-B1 reduces PV->PC connectivity and inhibition, resulting in increased seizure susceptibility and an ASD-like phenotype. Our findings underscore the crucial role of astrocytes in regulating inhibitory circuit development and discover a new role of EphB2 receptors in PV-specific inhibitory synapse development. Full Article
a Pre- and Postsynaptic MEF2C Promotes Experience-Dependent, Input-Specific Development of Cortical Layer 4 to Layer 2/3 Excitatory Synapses and Regulates Activity-Dependent Expression of Synaptic Cell Adhesion Molecules By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Experience- and activity-dependent transcription is a candidate mechanism to mediate development and refinement of specific cortical circuits. Here, we demonstrate that the activity-dependent transcription factor myocyte enhancer factor 2C (MEF2C) is required in both presynaptic layer (L) 4 and postsynaptic L2/3 mouse (male and female) somatosensory (S1) cortical neurons for development of this specific synaptic connection. While postsynaptic deletion of Mef2c weakens L4 synaptic inputs, it has no effect on inputs from local L2/3, contralateral S1, or the ipsilateral frontal/motor cortex. Similarly, homozygous or heterozygous deletion of Mef2c in presynaptic L4 neurons weakens L4 to L2/3 excitatory synaptic inputs by decreasing presynaptic release probability. Postsynaptic MEF2C is specifically required during an early postnatal, experience-dependent, period for L4 to L2/3 synapse function, and expression of transcriptionally active MEF2C (MEF2C-VP16) rescues weak L4 to L2/3 synaptic strength in sensory-deprived mice. Together, these results suggest that experience- and/or activity-dependent transcriptional activation of MEF2C promotes development of L4 to L2/3 synapses. Additionally, MEF2C regulates the expression of many pre- and postsynaptic genes in postnatal cortical neurons. Interestingly, MEF2C was necessary for activity-dependent expression of many presynaptic genes, including those that function in transsynaptic adhesion and neurotransmitter release. This work provides mechanistic insight into the experience-dependent development of specific cortical circuits. Full Article
a This Week in The Journal By www.jneurosci.org Published On :: 2024-11-06T09:30:07-08:00 Full Article
a See the Wonders of Bird Engineering in These Photos of Intricate Nests By www.smithsonianmag.com Published On :: Mon, 16 Sep 2024 17:00:00 +0000 In a new book, a curator at England's Natural History Museum describes rare and interesting nests and eggs—from the house sparrow to the village weaver—and the lessons they hold for avian conservation Full Article
a How Century-Old Paintings Reveal the Indigenous Roots and Natural History of New England Landscapes By www.smithsonianmag.com Published On :: Thu, 19 Sep 2024 12:00:00 +0000 Seven guest collaborators bring new eyes to a Smithsonian museum founder’s collection of American art Full Article
a The Colorful World of These Brazilian Identical Twins Bridges Dreams and Reality By www.smithsonianmag.com Published On :: Fri, 27 Sep 2024 16:30:03 +0000 The artists known as OSGEMEOS showcase the largest exhibition of their work in the United States at the Hirshhorn Museum and Sculpture Garden Full Article
a Ants Farmed Fungi in the Wake of Dinosaurs’ Demise 66 Million Years Ago By www.smithsonianmag.com Published On :: Thu, 03 Oct 2024 18:04:00 +0000 A new study from Smithsonian scientists analyzes ant and fungus species, and uncovers the origins of their close partnership Full Article
a What the Long History of Mail-In Voting in the U.S. Reveals About the Election Process By www.smithsonianmag.com Published On :: Fri, 04 Oct 2024 15:30:00 +0000 A recent exhibition shows how soldiers sent in votes during the Civil War and World War II, as many Americans would in 2020 following the spread of the Covid-19 pandemic Full Article
a See the Tools and Gadgets From Julia Child’s Kitchen That Reveal How the Beloved Chef Cooked By www.smithsonianmag.com Published On :: Mon, 07 Oct 2024 18:13:43 +0000 From the microwave to the food processor, the book author and television personality tried many appliances and devices to figure out the best ways to use them for her audience Full Article
a See 11 of the Best Wildlife Photographs From Years Past By www.smithsonianmag.com Published On :: Wed, 09 Oct 2024 18:30:40 +0000 A new book reveals striking images from six decades of the beloved Wildlife Photographer of the Year competition Full Article
a These 17 Pictures Tell the Stories of Black Athletes in America By www.smithsonianmag.com Published On :: Fri, 11 Oct 2024 19:20:13 +0000 A new book from the Smithsonian’s National Museum of African American History and Culture shows the images and impacts of athletes on and off the playing field Full Article
a How an Indigenous Weaver’s Mastery of Color Infuses Her Tapestries With a Life Force By www.smithsonianmag.com Published On :: Wed, 16 Oct 2024 18:17:46 +0000 The work of Diné artist DY Begay, now on view at the National Museum of the American Indian, blends tradition and modernity Full Article
a Could Anyone Bring an Extinct Animal Back to Life? And More Questions From Our Readers By www.smithsonianmag.com Published On :: Fri, 18 Oct 2024 15:00:00 +0000 You’ve got questions. We’ve got experts Full Article
a From Candy to Lightbulbs, Felix Gonzalez-Torres Showed Life and Loss Through Everyday Objects By www.smithsonianmag.com Published On :: Mon, 21 Oct 2024 17:50:52 +0000 A new exhibition co-presented by the National Portrait Gallery and the Archives of American Art explores the seminal artist’s work Full Article
a Why the Creator of One of the First ‘Lie Detectors’ Lived to Regret His Invention By www.smithsonianmag.com Published On :: Tue, 22 Oct 2024 11:00:00 +0000 The early polygraph machine was considered the most scientific way to detect deception—but that was a myth Full Article
a This Captivating Guide Uncovers the History and Mystery of Dinosaurs in 50 Fossils By www.smithsonianmag.com Published On :: Tue, 29 Oct 2024 17:16:07 +0000 A paleontologist at the Natural History Museum in London chronicles the age of the famous and fascinating massive reptiles Full Article
a See What Happened When One Museum Asked Artists to Define ‘Home’ By www.smithsonianmag.com Published On :: Mon, 04 Nov 2024 15:30:00 +0000 The Smithsonian Design Triennial presents 25 commissions that explore the physical and conceptual ideas of shelter and refuge Full Article
a Quincy Jones Was a ‘Musician’s Musician’ Who Was Uniquely Beloved in the Cutthroat Music Industry By www.smithsonianmag.com Published On :: Mon, 04 Nov 2024 20:30:37 +0000 A Smithsonian curator reflects back on the artistic legend, a "Renaissance man" with 28 Grammys to his name, who died Sunday at 91 years old Full Article
a This Stunning New Atlas Explores Humanity’s Ancient Relationship With Space and the Universe By www.smithsonianmag.com Published On :: Wed, 06 Nov 2024 19:00:31 +0000 Written by the former chief historian of NASA, the book examines the evolution of our cosmic understanding—from early civilizations to the present day Full Article
a See a Film That Reimagines History on the Malaysian Island That Served as a Refugee Site After the Vietnam War By www.smithsonianmag.com Published On :: Thu, 07 Nov 2024 16:11:03 +0000 The work, now on view at the Smithsonian American Art Museum, tells the story of two characters on the island—the last people alive in the world Full Article
a France to collaborate on FAO strategic objectives By www.fao.org Published On :: Mon, 03 Feb 2014 00:00:00 GMT FAO and French research institutions will step up cooperation in key research areas and coordinate their actions within the global framework of FAO’s renewed strategy. Two agreements signed today cover a [...] Full Article
a Nutrition and food safety remain top priorities for FAO and WHO By www.fao.org Published On :: Fri, 14 Feb 2014 00:00:00 GMT FAO and the World Health Organization (WHO) will continue to work closely on nutrition, food safety and antimicrobial resistance issues, FAO Director-General José Graziano da Silva and WHO Director Margaret [...] Full Article
a FAO Director-General applauds UN Secretary-General's stance on hunger By www.fao.org Published On :: Wed, 07 May 2014 00:00:00 GMT FAO Director-General José Graziano da Silva today praised UN Secretary-General Ban Ki Moon for his support in the fight against hunger at a meeting with FAO member countries, the Committee [...] Full Article
a Six months after disaster, Philippine farmers bring in the harvest By www.fao.org Published On :: Wed, 07 May 2014 00:00:00 GMT Tens of thousands of farmers are bringing in their first rice harvest just six months after one of the worst typhoons to ever hit the Philippines left their fields in [...] Full Article
a Latin America and the Caribbean redouble efforts to eradicate hunger By www.fao.org Published On :: Wed, 07 May 2014 00:00:00 GMT Representatives of all countries in Latin America and the Caribbean have gathered here this week to agree on the actions needed to definitively eradicate hunger in the region before 2025. [...] Full Article
a Crisis-hit farmers receive seeds and tools in Central African Republic By www.fao.org Published On :: Fri, 16 May 2014 00:00:00 GMT A major operation to distribute seeds and tools has been launched in the Central African Republic to support [...] Full Article
a Pope Francis to attend the Second International Conference on Nutrition (ICN2) By www.fao.org Published On :: Tue, 20 May 2014 00:00:00 GMT Pope Francis will add his voice to the fight against hunger and malnutrition by addressing the Second International [...] Full Article
a FAO urges global commitment to tackle world's nutrition challenges By www.fao.org Published On :: Wed, 21 May 2014 00:00:00 GMT FAO Director-General José Graziano da Silva today called on countries to put nutrition high on their national and international agendas, and to take a lead role in the upcoming Second [...] Full Article
a Countries recognize vital role of small-scale fishers By www.fao.org Published On :: Tue, 10 Jun 2014 00:00:00 GMT Countries today endorsed a set of wide-reaching guidelines that will boost the already vital [...] Full Article