bioRxiv Subject Collection: Neuroscience's Journal

Inflammation-enhanced synapse-specific phagocytosis by adult APP microglia in a microfluidic neuron-microglia co-culture model
Microglia play a critical role in synapse remodeling and neuroinflammation, both of which are dysregulated in Alzheimer's disease (AD). However, most in vitro models rely on neonatal or immortalized microglia, limiting their relevance to adult pathophysiological context. Here, we present a compartmentalized microfluidic co-culture platform that enables spatially controlled interactions between primary cortical neurons and adult microglia from wild-type (WT) and APP-transgenic mice. This system allows precise functional analysis of microglia-synapse interactions under defined inflammatory conditions. Upon lipopolysaccharide (LPS) stimulation, APP microglia exhibited exaggerated morphological activation, elevated IL-1{beta} secretion, and selectively increased engulfment of synaptic material. In contrast, phagocytosis of non-specific substrates such as pHrodoTM Zymosan remained unchanged, suggesting a substrate-specific enhancement of microglial phagocytic activity. Blocking the complement receptor CD11b abolished the LPS-induced increase in synaptic uptake, confirming the role of complement-dependent pathways. Transcriptomic profiling revealed robust inflammatory responses in both genotypes, with selectively heightened expression of proinflammatory genes in APP microglia, consistent with a primed immune phenotype. Importantly, increased synaptic uptake occurred without measurable loss of global synaptic connectivity, highlighting the specificity and sensitivity of the system to detect microglial functional changes. This model captures genotype-dependent microglial reactivity (revealing phenotypes not fully captured by transcriptomic profiling) and provides a physiologically relevant, tractable in vitro platform for dissecting microglial contributions to synaptic pathology in neurodegenerative disease.

Pre-conscious reactions to faces as the biological roots of emotion perception
Bodies respond to others emotions through subtle physiological changes. Whether these responses require conscious emotion recognition is debated. Here, we examined the relationship between visual awareness and physiological arousal in response to emotional faces. We recorded facial electromyography (EMG), electrodermal activity (EDA), and pupil dilation during the presentation of fearful, happy, and neutral faces, as well as their phase-scrambled versions, to the left eye. Meanwhile, rapidly changing Mondrian patterns were displayed to the right eye to suppress the left-eye stimuli. Participants pressed a button when they noticed a change from the flickering mask. This setup allowed us to compare behavioural and physiological responses during conscious versus subconscious processing of emotional content. Results showed faster breakthrough times for happy faces and moderate physiological responses to emotional information, even without conscious perception. Specifically, pupils and facial EMG were more responsive to fearful than to happy or neutral expressions. EDA was higher for faces compared to control stimuli, regardless of the emotional expression. Once visual awareness was established, emotional expressions elicited distinct responses that aligned with the perceived emotion. An exploratory analysis revealed a negative correlation between pupil dilation and autistic, alexithymic, and schizotypal traits, whereas empathy traits correlated positively. Our findings highlight the role of subcortical visual processing in detecting emotionally relevant stimuli and show that social abilities are linked to the physiological processing of emotions at a subconscious level. They underscore how subcortical mechanisms interact with the autonomic nervous system, enhancing our understanding of the biological foundations of emotion perception.

PMAT enhances sexual dimorphism of fear behaviors and facilitates female mice's generalized contextual fear extinction
Enhanced signaling of dopamine and/or serotonin during highly arousing situations can be reduced or terminated by monoamine transporters. One such transporter, plasma membrane monoamine transporter (PMAT, Slc29a4), attenuates both dopamine and serotonin signaling. An absence of selective pharmacological inhibitors means genetically modified mice constitutively deficient in PMAT remain the best tool with which to study PMAT's organism-level functional effects. Fear conditioning is a high arousal process. Generalization of fear is an evolutionarily advantageous process, whereby information learned from one experience is applied to other new but similar encounters. Pathological fear generalization, in contrast, is a core feature of most anxiety disorders. Given our previous findings indicating PMAT function reduces male mice's context fear and enhances extinction of female mice's cued fear, we hypothesized that PMAT would similarly reduce generalization (i.e., enhance discrimination) of context and cued fear in male and female mice, respectively. Our context and cued fear conditioning experiments in adult PMAT wildtype (+/+) and heterozygous (+/-) male and female mice partially supported our hypotheses. We discovered PMAT functions to facilitate extinction of contextually generalized fear, plus subsequent extinction of context-specific fear, selectively in females. Moreover, when specific fear cues or contexts were temporally presented before cues or contexts that were similar enough to make generalization possible, PMAT enhanced biological sex differences. Growing evidence reports common PMAT polymorphisms elicit measurable effects when PMAT function is reduced. Thus, we suspect future experiments may reveal positive associations between PMAT polymorphisms and risk for anxiety disorder symptoms, particularly in people assigned female at birth. Inclusion of these genetic variations in pharmacogenomic analyses may prove therapeutically beneficial.

Identification of molecular nociceptors in Octopus vulgaris through functional characterisation in Caenorhabditis elegans
Nociception, a phenomenon crucial for animal survival, deploys evolutionarily conserved molecular mechanisms. Among invertebrate species, cephalopods are of particular interest as they possess a well-developed brain speculated to be able to encode pain-like states. This has led to their inclusion in the Directive 2010/63 EU for welfare protection. However, the molecular mechanisms of nociception in cephalopods are still poorly characterised and it is important to address this knowledge gap to better understand cephlapods capacity to express pain states. Here we describe a bioinformatic pipeline utilising conserved nociceptive genes, to identify the orthologous candidates in the Octopus vulgaris transcriptome. We identified 51 genes we predict to function in nociception. These add to the mechanosensory TRPN and the unique chemotactile receptors recently identified in octopus suckers, thus expanding the set of genes that merit further functional characterisation in cephalopods. We therefore selected 38 orthologues in Caenorhabditis elegans, a tractable experimental platform and tested loss of function mutant strains of distinct functional gene classes (e.g., osm-9, egl-3, frpr-3) in a low pH avoidance paradigm. This identified 18 nociceptive-related genes to be prioritised for further functional characterisation in O. vulgaris.

Probing the content of semantic representations in body-selective regions
The extrastriate body area (EBA) has been known to selectively respond to human body parts, but recent work suggests it may encode richer scene semantics. However, it remains unclear what aspects of natural scenes constitute the semantic representation in the EBA. Here we address this question by analyzing the relationship between object co-occurrence in natural scene captions and EBA responses predicted by caption-based encoding models. This revealed object category pairs associated with EBA activity, leading to the hypothesis that EBA encodes the speed of human body motion implied in scenes. A subsequent behavioral experiment and correlation analyses confirmed this, showing strong correlations between EBA responses and implied motion ratings. In addition, the representation of implied body motion extends into the fusiform body area (FBA). Variance partitioning further showed that while body-related features such as the number of people and body size also contributed, implied motion uniquely explained the largest portion of EBA and FBA responses. Overall, semantic representations in body-selective regions are jointly shaped by multiple body-related features, with implied motion as the primary contributor. Our co-occurrence-based approach, combined with brain-to-model mapping methods, offers a novel, interpretable framework for understanding high-level visual representations in natural scene perception.

MCA: A Multicellular analysis Calcium Imaging toolbox for ImageJ
Functional imaging using genetically encoded indicators, such as GCaMP, has become a foundational tool for in vivo experiments and allows for the analysis of cellular dynamics, sensory processing, and cellular communication. However, large scale or complex functional imaging experiments pose analytical challenges. Many programs have worked to create pipelines to address these challenges, however, most platforms require proprietary software, impose operational restrictions, offer limited outputs, or require significant knowledge of various programming languages, which collectively can limit utility. To address this, we designed MCA (a Multicellular Analysis toolkit) to work with ImageJ, a widely used open-source software which has been the standard image analysis platform for the last 30 years. We developed MCA to be visually intuitive, utilizing ImageJs platform to generate new images based on completed tasks so users can visually see each step in the analysis pipeline. In addition, MCA implements a user-friendly GUI providing a simple interface which resembles other native ImageJ plugins. We incorporated functionality for rigid registration to correct motion artifacts, algorithms for cell body prediction, and methods for annotating cells and exporting data. For cell prediction, we trained a custom model in Cellpose 2.0 for segmentation of nuclei expressing pan-neuronal nuclear localized GCaMP in zebrafish. We validated the accuracy of MCA output to previously published zebrafish calcium imaging data which elicited visually evoked neuronal responses. To show the versatility of MCA, we also show that our software can be utilized for multiple sensory modalities, brain regions, and multiple model organisms including Drosophila and mouse. Together these data show that MCA is viable for extracting calcium dynamics in a user-friendly environment for multiple forms of functional imaging.

GPC5 expression highlights astrocytic heterogeneity and divergent hippocampal responses in Alzheimer's and Parkinson's Dementia
Astrocytes are central to central nervous system (CNS) homeostasis and memory consolidation. They also display remarkably heterogeneous morphological phenotypes, functions and molecular profiles between and within distinct regions of the human brain. Yet, their role in regional vulnerability in neurodegenerative diseases (NDDs) remains poorly understood. To elucidate this subregional heterogeneity of astrocytes in the hippocampus and parahippocampal cortex and its implication for neurodegeneration, we employed high-content neuropathology, integrating chromogenic immunohistochemistry (cIHC) and digital pathology, to map and quantify the expression of functional astrocytic markers (GFAP, ALDH1L1, AQP4, GPC5 and ALDH7A1) of healthy individuals, of patients with Alzheimer's disease (AD) or Parkinson's disease with dementia (PDD). We found that astrocytic markers followed distinct expression patterns in AD and PDD. In AD, GFAP was strongly reduced in specific hippocampal regions, whereas AQP4 was increased and GPC5 expression, although regionally stable, was locally associated with amyloid and tau pathology. In PDD, astrocytic responses were characterized by selective decreases in ALDH1L1 and ALDH7A1, with GFAP and GPC5 remaining largely unaffected. Notably, GFAP and GPC5 expression delineated distinct astrocytic subtypes that were differentially distributed across hippocampal subfields and showed specific responses to AD and PD pathologies. These findings provide new insights into the landscape of astrocytic heterogeneity in the human hippocampus and beyond, revealing disease- and region-specific astrocytic signatures. Importantly, they underscore the value of incorporating novel markers such as GPC5 to fully capture astrocytic diversity and to better understand astrocyte contributions to neurodegeneration.

α-Synuclein driven cell susceptibility in Parkinson's disease
Early cellular events in Parkinson's disease (PD) remain elusive. While aggregation of -synuclein (Syn) into Lewy bodies marks advanced pathology, smaller Syn oligomers have been implicated in prodromal stages. Here we map Syn oligomers at single-particle resolution in post-mortem brain tissue from Braak stage 3/4 PD cases and matched controls. Quantitative imaging of 9,882 neurons across four regions captured over 112 million Syn oligomers. Mean intracellular Syn burden was unchanged between groups, but PD samples contained a higher fraction of neurons whose oligomer load exceeded a specific aggregation threshold. We term these aggregation-susceptible cells (ASCs). ASC enrichment in vulnerable regions supports a population-level model in which early pathology arises from a stochastic shift in cellular composition rather than altered Syn aggregation kinetics. This human-tissue, large-scale dataset provides a quantitative framework for detecting ASCs and for testing population-level interventions in PD and related proteinopathies.

Investigating motion-induced signal corruption in steady-state diffusion MRI
Purpose: Diffusion-weighted steady-state free precession (DW-SSFP) is a diffusion imaging sequence achieving high SNR efficiency and strong diffusion-weighting. A key challenge for in vivo DW-SSFP is the sequence's severe motion sensitivity, currently limiting investigations to low or no motion regimes. Here we establish a framework to both (1) investigate and (2) correct for the impact of subject motion on the DW-SSFP signal. Theory and Methods: An extended phase graphs (EPG) representation of the DW-SSFP signal was established incorporating a motion operator describing rigid body and pulsatile motion. The representation was validated using Monte Carlo simulations, and subsequently integrated into a data fitting routine for motion estimation and correction. The fitting routine was evaluated using both simulations and experimental 2D low-resolution single-shot timeseries DW-SSFP data acquired in a human brain, with a tensor reconstructed from the motion-corrected experimental DW-SSFP data. Results: The proposed EPG-motion framework gives excellent agreement to complementary Monte Carlo simulations, demonstrating that diffusion coefficient estimation is robust over a range of motion and SNR regimes. Tensor estimates from the motion-corrected experimental DW-SSFP data give excellent visual agreement to complementary DW-SE data acquired in the same subject. Conclusion: Temporal information capturing the evolution of the DW-SSFP signal can be used to retrospectively (1) estimate subject motion and (2) reconstruct motion-corrected DW-SSFP data. Open-source software is provided, facilitating future investigations into the impact of subject-motion on DW-SSFP acquisitions.

Social Touch Suppresses Aggression via Thalamic Mechanisms
Understanding the neural circuitry underlying aggression is critical for both scientific insight and clinical intervention. Here, we identify the posterior intralaminar thalamic nucleus (PIL) as a key node in an anti-aggressive circuit activated by social touch. Using a rodent model, we demonstrate that deprivation of direct physical contact during social isolation leads to heightened aggression. Chemogenetic and optogenetic manipulations reveal that PIL neurons activated by social touch inhibit aggression via excitatory projections to the medial preoptic area (MPOA) of the hypothalamus. This PIL-to-MPOA pathway is suppressed by input from the ventromedial hypothalamic nucleus (VMH). Our findings establish a novel thalamic-hypothalamic circuit that mediates social touch-induced suppression of aggression, offering potential targets for therapeutic intervention in conditions marked by pathological aggression.

Tension shapes memory: Computational insights into neural plasticity
Mechanical forces have recently emerged as critical modulators of neural communication, yet their role in high-level cognitive functions remains poorly understood. Here, we present a biologically inspired spiking neural network model that integrates mechanical tension, vesicle dynamics, and spike-timing-dependent plasticity to examine how tension influences learning, memory, and cognitive operations such as pattern completion, projection, and association. We find that increased tension enhances synaptic efficiency by accelerating vesicle clustering and recovery, resulting in a 67% improvement in memory recall speed and a 17% increase in inter-regional synchrony during projection relative to relaxed states. Conversely, a 20% reduction in tension leads to a 31% decline in memory association performance, highlighting the tension-sensitive accessibility of stored information. The model further reveals that networks with 20% inhibitory neurons achieve optimal spatial precision in memory encoding and recall. Together, these in silico findings position mechanical tension as a functional neuromodulator and suggest new directions for neuromorphic design and energy-efficient, living computing platforms.

Multi-tier signaling and epigenomic reprogramming orchestrate microglial inflammatory states and functions associated with demyelination
The extensive heterogeneity of microglia inflammatory states accompanying neurodegenerative diseases underscores the complex molecular mechanisms that regulate these cells. Here, we report on transcriptional effectors that control microglial inflammatory polarization associated with brain demyelination in mice. Using flow cytometry, microscopy and RNA-seq, we identified two dominant, functionally distinct states of Clec7a+CD229+ inflammatory microglia, discriminated from one another by CD11c expression. Epigenomic analyses implicated genome-wide nucleosome remodeling to the polarization process, driven by state-associated stimulation of transcription factors that included Pu.1, AP-1, Bhlhe40 and Egr2, as well as re-calibration of homeostatic input provided by Mef2. Loss-of-function experiments validated the physiological relevance of Trem2, Mef2a and Egr2 to the microglial inflammatory polarization process in the demyelinating brain. Therefore, distinct configurations of signaling input cooperate with epigenetic mechanisms to reprogram the transcriptional output of microglia to enable their inflammatory functions.

Treefrogs exploit temporal onset synchrony and harmonicity in forming auditory objects of vocal communication signals
Animals frequently communicate in dense social aggregations characterized by the presence of overlapping signals from multiple individuals. Receivers have to perceptually organize these overlapping signals into distinct auditory objects, each corresponding to the perceptual representation of an individual signal. All the signal components produced by the same individual should be integrated into a unitary auditory object while those produced by distinct individuals should be segregated. The principles of auditory object formation and their importance in vocal communication are less understood in non-human animals relative to humans. Here, using American green treefrogs, Hyla cinerea, we tested the hypothesis that receivers exploit the relative timing and harmonic relatedness of multiple spectral components to integrate or segregate sounds during auditory object formation. Using phonotaxis as a behavioral assay, females were given a choice between an attractive conspecific call consisting of three spectral components and a composite call consisting of the same three conspecific spectral components to which we added three spectral components from the call of a heterospecific sister species (Hyla gratiosa). The addition of heterospecific components to conspecific calls renders them less attractive. Across treatments, we manipulated the relative onset timing and harmonic relatedness of the heterospecific components in relation to the conspecific components. We predicted that asynchronous temporal onsets and inharmonic relationships between the conspecific and heterospecific components would promote their perceptual segregation. Our findings are consistent with this prediction. We discuss these findings in the light of parallel perceptual processes across animal taxa and neuroethological theories of auditory processing.

An AlphaFold guided model for the evolution of the CaMKII interactome
The neuronal functions of mammalian calcium calmodulin (Ca2+.CAM) dependent protein kinase II (CaMKII) are orchestrated by an interactome of multiple CaMKII-protein interactions when Ca2+.CAM opens the kinase domain to bind Ca2+ response regulators and substrates to its regulatory helix and C-lobe, respectively. We analysed over forty 3D-atomic structures and models of CaMKII-target complexes to track the evolution of the neuronal CaMKII interactome over three model organisms and the early metazoan Trichoplax adhaerans. We report the conservation of the molecular interactome based on binding surface overlap, energy frustration and fold evolution. Transcriptome databases informed on Ca2+ CaMKII response regulation and colocalization with substrates. The activation machinery was invariant, but the co-expression of CaMKII and its substrates relative to the mammalian isoform was progressively reduced in simpler organisms. We propose CaMKII architecture for autoinhibition, Ca2+ response and substrate association was formed for neurosecretion, then specialised for synaptic signalling with the alpha-isoform.

HCN channels reveal conserved and divergent physiology in supragranular pyramidal neurons in primate species
The physiological properties of human and rodent neurons differ, yet the extent to which these differences reflect human specializations is often unclear. Compared with their rodent counterparts, human supragranular pyramidal neurons possess enriched HCN-channel-dependent intrinsic membrane properties and a related sensitivity to synaptic inputs containing delta/theta band frequencies. We tested whether other primate species possess enriched HCN-channel dependent membrane properties. We found ubiquitous HCN1 subunit gene expression in supragranular glutamatergic neurons across New World Monkeys, Old-World Monkeys, and great apes in single nucleus RNA-sequencing datasets. Using Patch-seq recordings from acute and cultured brain slices, we found robust HCN-dependent physiological properties in supragranular pyramidal neurons in a species of New-World monkey (Saimiri sciureus) and two species of Old-World Monkey (Macaca mulatta, Macaca nemestrina). In both human and macaque neocortex, HCN-related intrinsic properties increased in magnitude with increasing laminar depth, especially in one transcriptomic cell type. Within this type, HCN dependent properties were more pronounced in macaque than human neurons. These findings indicate that HCN-governed membrane properties and sensitivity to delta/theta band frequencies are roughly conserved in supragranular pyramidal neurons across at least 36 million years of primate evolution.

Dopamine supports reward prediction to constrain reward seeking
Reward-predictive cues trigger dopamine release in the nucleus accumbens core (NAc). This signal has long been thought to mediate motivation. However, understanding of dopamine function is complicated by the fact that reward cues not only motivate reward pursuit, but also enable the reward predictions that shape how reward is pursued. Thus, here we used dopamine sensor fiber photometry, cell-type and pathway-specific optogenetic inhibition, Pavlovian cue-reward conditioning, and test of cue-induced reward-pursuit strategy in male and female rats, to ask how cue-evoked phasic dopamine release supports reward pursuit. Cues that predicted imminent reward with high probability triggered a large NAc dopamine response and checking for the expected reward in the delivery location, rather than exploratory reward seeking. Cues that predicted reward with low probability elicited less dopamine and biased towards motivation to seek, rather than check for reward. Cue-evoked dopamine inversely related to and predicted reward seeking. Correspondingly, yet surprisingly, inhibition of cue-evoked NAc dopamine increased reward-seeking motivation and decreased reward checking. Thus, cue-evoked NAc dopamine is positively modulated by high imminent reward prediction to constrain exploratory reward-seeking motivation in favor of a more focal reward-checking strategy. These data advance understanding of dopamine function by indicating dopamine does not simply promote reward-seeking motivation, but rather supports reward predictions to shape adaptive reward pursuit strategy.

Activity-driven proprioceptive synaptic refinement in the developing spinal cord by complement signaling mechanisms
Proprioceptive group Ia afferents detect muscle stretch to guide effortless and purposeful movement and make monosynaptic connections with spinal -motor neurons to mediate reflexes, such as the stretch reflex. It is thought that proprioceptive Ia afferents target motor neurons of the same spinal segment; yet, how this specificity, if any, is established during early development is unknown. Using ex vivo spinal cord electrophysiology preparations from neonatal mice of both sexes, we identified a developmental period during which proprioceptive la afferents evoke both segmental and intersegmental responses at monosynaptic latencies. We provide anatomical evidence that motor neurons in the lumbar segment 4 (L4) receive direct input from proprioceptive Ia afferents in L5 during early postnatal development. Intersegmental responses (L4/L5) were prominent at postnatal days (P) 4-7 but were virtually absent by P11-13. To test the role of proprioceptor activity on segmental specification, we analyzed Nav1.6 conditional knockout mice (Nav1.6cko), in which proprioceptor signaling is impaired, and found that intersegmental responses persist up to P11-13 but were absent in age-matched floxed controls. We predict this is due to impaired activation of complement signaling pathways, as Nav1.6cko mice showed reduced C1qA expression in the ventral spinal cord at P9. Consistent with this, C1qA knockout mice also retain intersegmental responses at P11-13. Collectively, these findings identify an important postnatal window during which segmental specificity of proprioceptive circuits emerges and suggest that proprioceptor activity induces C1qA-mediated elimination of excessive intersegmental connectivity.

Development of an RNA Aptamer as a Therapeutic Agent for Synucleinopathies
The aggregation of -synuclein (Syn), a 140-mer protein, has been implicated in the pathogenesis of Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. KTKEGV repeats (KR) of Syn are key mediators of prion-like propagation and neurodegeneration. Despite the availability of symptomatic treatments, no current therapy effectively delays disease progression. Here we report a 77-nucleotide (nt) RNA aptamer (1R6) with potent affinity and selectivity for Syn1-95 (KD = 18 nM) through in vitro selection. 1R6 significantly inhibited Syn oligomerization and {beta}-sheet-rich fibril assembly and promoted disaggregation of preformed fibrils. Additionally, 1R6 suppressed Syn seeding, as determined by FRET-based cellular biosensor cell assay. Cellular studies revealed that 1R6 cotransfection completely prevented Syn-induced cytotoxicity. To assess the protective effects of 1R6 in vivo, we used a Drosophila melanogaster model expressing human Syn in neurons. Flies fed with 1R6 showed improved locomotor defects, reduced photoreceptor degeneration, and decreased Syn levels in the head. Structural characterization through 1H-15N heteronuclear multiple quantum correlation nuclear magnetic resonance experiments demonstrated that 1R6 targets KR motifs, a finding further supported by in silico simulations. Our findings indicate that RNA aptamers, such as 1R6, may represent promising therapeutic candidates for synucleinopathies, thus opening new avenues in the treatment of these diseases.

Mechanistic basis of dynamic and heterogeneous divisive normalization in visual cortex
Neocortical computation emerges from the dynamic interplay of excitation and inhibition, operating in a loose balance regime where recurrent and external inputs contribute comparably to neuronal activity. Neurons display broad heterogeneity in synaptic inputs and firing rates, making it essential to explain the full distribution of responses, not just the mean, when elucidating mechanisms of dynamics and computation. We examined divisive normalization in mouse visual cortex using population calcium imaging of excitatory and parvalbumin (PV) inhibitory neurons, combined with computational models of varying complexity. We found that suppression in PV neurons was transiently reduced, driven by the dynamics of subcortical input, and that heterogeneity in suppression strength was linked to population correlations, variability in excitatory-inhibitory balance, and suppression of both subcortical and local cortical inputs. Our results link local recurrent connectivity to the diversity of normalizing responses in cortex, providing a mechanistic basis for functional heterogeneity in this computation.

Screening channelrhodopsins using robotic intracellularelectrophysiology and single cell sequencing
Background: Our ability to engineer opsins is limited by an incomplete understanding of how sequence variations influence function. The vastness of opsin sequence space makes systematic exploration difficult. New method: In recognition of the need for datasets linking opsin genetic sequence to function, we pursued a novel method for screening channelrhodopsins to obtain these datasets. In this method, we integrate advances in robotic intracellular electrophysiology (Patch) to measure optogenetic properties (Excite), harvest individual cells of interest (Pick) and subsequently sequence them (Sequence), thus tying sequence to function. Results: We used this method to sequence more than 50 cells with associated functional characterization. We further demonstrate the utility of this method with experiments on heterogeneous populations of known opsins and single point mutations of a known opsin. Of these point mutations, we found C160W ablates the response of ChrimsonR to light. Conclusion and comparison to existing methods: Compared to traditional manual patch clamp screening, which is labor-intensive and low throughput, this approach enables more efficient, standardized, and scalable characterization of large opsin libraries. This method can enable opsin engineering with large datasets to increase our understanding of opsin sequence function relationships.

Uncovering executive function profiles within interindividual variability: A data driven clustering exploration of design fluency in school-aged children
This study applied unsupervised machine learning to performances on a design fluency task, to identify distinct executive function (EF) profiles among 113 neurotypical Canadian children (62% female, 74% White, aged 7-13). By tracking design, repetition, and strategy production every minute for five minutes, the results revealed two profiles: Profile A generated fewer designs but exhibited a more stable production pattern across time. Profile B, initially more productive, showed a steeper increase in repetition errors and a decline in design production. These findings demonstrate how EF interindividual variability in neurotypical children can be captured through naturally emerging performance patterns, highlighting the value of temporal analysis in differentiating executive functioning profiles.

Pharmacological potentiation of Nav1.1 channels in interneurons mitigates tau depositions and neuronal death in a mouse model of neurodegenerative dementias
Epileptiform discharges and neuronal hyperexcitability are key pathophysiological features of Alzheimer's disease and related tauopathies. We previously identified selective dynfuntion of parvalbumin-positive GABAergic interneurons (PV neurons), which regulate neural network excitability, in a tauopathy mouse model. However, the mechanistic link between PV neuron deficits, tau pathology, and neurodegeneration remains unclear. Here, we demonstrate that pharmacological enhancement of phasic PV neuron activity markedly attenuates tau accumulation and neuronal loss in a tauopathy mouse model. We developed DSR-143630, a novel activator of voltage-gated sodium channel Nav1.1, selectively expressed in PV neurons. Administration of DSR-143630 alleviated febrile seizures in Nav1.1 haploinsufficient mice and suppressed high-frequency oscillations (HFOs), an electrophysiological signature of hyperexcitability associated with cognitive impairments, in rTg4510 tau transgenic mice. Longitudinal tau PET and volumetric MRI demonstrated that DSR-143630 treatment from 4 to 11 months of age profoundly reduced age-dependent tau deposition and atrophy in the neocortex and hippocampus. Postmortem analyses further revealed decreased levels of phosphorylated tau, preservation of neuronal populations, and attenuated neuroinflammatory responses, including reactive gliosis. These findings establish PV neuron dysfunctions and consequent network hyperexcitability as key drivers of tau pathogenesis and highlight pharmacological Nav1.1 activation as a promising disease-modifying strategy for neurodegenerative tauopathies.

Integrative Transcriptomic Analysis Identifies Novel Mitochondrial Gene Targets in Parkinson's Disease.
Parkinson's disease (PD) involves the progressive loss of dopaminergic (DA) neurons within the substantia nigra (SN) region of the midbrain, although the precise molecular processes driving this degeneration are still not fully understood. This research investigates the expression patterns of genes associated with mitochondrial function in the SN and DA neurons of individuals with PD, aiming to uncover new potential therapeutic targets. Two independent RNA sequencing datasets, GSE7621 and GSE8397 (GPL-96), retrieved from the GEO database, were analyzed to identify mitochondria-related genes that are differentially expressed in the SN of PD patients. Gene Ontology and pathway enrichment analyses were also performed to gain insight into the molecular mechanisms involved. To validate our findings, we utilized an additional dataset, GSE49036. We also examined the altered expression of these mitochondrial-related genes in DA neurons using RNA-seq data from GSE169755, which includes DA neurons isolated from the SN of both PD patients and healthy controls. Finally, the proposed hypothesis was tested experimentally using an in vitro model of PD. This integrative analysis across multiple datasets reveals previously unrecognized mitochondrial gene candidates implicated in PD pathogenesis and highlights their potential as targets for therapeutic intervention.

Controlling malaria mosquito reproduction via the octopamine beta2 receptor
Mosquito reproduction in a broad sense involves multiple steps from acoustic recognition of mating partners to egg hatching. We show that the octopamine receptor AgOct{beta}2R controls different aspects of this process in a sexually dimorphic manner. AgOct{beta}2R knockout males present auditory defects that impair their ability to inseminate females, whilst knockout females are sterile. These phenotypes suggest AgOct{beta}2R as a target to impair mosquito reproduction at multiple levels. We test the reproductive effects of the insecticide amitraz, an AgOct{beta}2R agonist, showing that amitraz exposure reduces insemination in the lab but not in the field and has no effects on female sterility, excluding its applicability as a mating disruptor. Pharmacological assays reveal that AgOct{beta}2R sensitivity to amitraz is reduced compared to other arthropods, but its responses can be altered by modifying residues in the binding pocket. Together, our results establish AgOct{beta}2R as a promising target to disrupt mosquito reproduction but emphasize the necessity of developing new tools to exploit this approach.

A Deep Neural Network Trained on Congruent Audiovisual Speech Reports the McGurk Effect
In the McGurk effect, incongruent auditory and visual syllables are perceived as a third, illusory syllable. The prevailing explanation for the effect is that the illusory syllable is a consensus percept intermediate between otherwise incompatible auditory and visual representations. To test this idea, we turned to a deep neural network known as AVHuBERT that transcribes audiovisual speech with high accuracy. Critically, AVHuBERT was trained only with congruent audiovisual speech, without exposure to McGurk stimuli or other incongruent speech. In the current study, when tested with congruent audiovisual "ba", "ga" and "da" syllables recorded from 8 different talkers, AVHuBERT transcribed them with near-perfect accuracy, and showed a human-like pattern of highest accuracy for audiovisual speech, slightly lower accuracy for auditory-only speech, and low accuracy for visual-only speech. When presented with incongruent McGurk syllables (auditory "ba" paired with visual "ga"), AVHuBERT reported the McGurk fusion percept of "da" at a rate of 25%, many-fold greater than the rate for either auditory or visual components of the McGurk stimulus presented on their own. To examine the individual variability that is hallmark of human perception of the McGurk effect, 100 variants of AVHuBERT were constructed. Like human observers, AVHuBERT variants was consistently accurate for congruent syllables but highly variable for McGurk syllables. Similarities between the responses of AVHuBERT and humans to congruent and incongruent audiovisual speech, including the McGurk effect, suggests that DNNs may be a useful tool for interrogating the perceptual and neural mechanisms of human audiovisual speech perception.

Effect of acute elevated magnesium on bursting activity and information-processing dynamics in cortical cultures
Magnesium (Mg2+) plays a significant role in hippocampal memory and learning and is implicated in a variety of neurological disorders, such as migraine. Despite this crucial role Mg2+ has on brain health, its effect on the dynamics of networks of neurons is still not fully understood. This study investigates the impact of several doses of elevated extracellular Mg2+ on organotypic cultures. Cultures were recorded on a 512-microelectrode array and analyzed using the burstiness index (BI), the rate of network wide bursts relative to other neuronal activity. We also use a suite of information theoretic measures to further establish the role Mg2+ plays in the brain. Elevated Mg2+ is found to have a dose-dependent increase on BI caused by a loss of network activity not contained within a burst or high firing rate activity. Information dynamics further show that the network experiences a loss of entropy and an increase in time-reversibility, connectivity, and transfer of redundant information. These factors indicate that Mg2+ causes a loss of complex activity and an increase in highly integrated, constant dynamics. This lays the groundwork for a deeper examination of the role Mg2+ plays in learning, memory and treating neurological disorders.