bioRxiv Subject Collection: Neuroscience's Journal

Birth order specified recruitment of motor circuits during spontaneous neural activity in zebrafish embryo
Modular organization of spinal neural circuits control dynamic regulation of locomotion. However, it is unknown when or how the distinct microcircuits emerge during development. We carried out high-resolution calcium imaging of neural activity driving the first motor behavior in the zebrafish embryo. During this period, at least two waves of neurogenesis occur to generate primary and secondary motoneurons. We found that embryos containing only primary motoneurons exhibit a single highly synchronized rhythmic circuit between the interneurons and motoneurons. Later, embryos with both primary and secondary motoneurons have two distinct interneuron-motoneuron circuits, one containing primary motoneurons displaying low-frequency activity and the other containing secondary motoneurons with high-frequency activity. The results indicate a mode of birth order determined microcircuits where neurons that are born together are recruited together. Nicotine affected neuronal activity frequency, revealing a functional role for cholinergic signaling in the emergence of patterned spinal microcircuits. Indeed, we found aberrant arrhythmic synchronized activity in mutants for cholineacetyltransferase-a where acetylcholine is no longer synthesized. Overall, we reveal the sequential recruitment of birth order specified microcircuits during the emergence of the earliest motor behavior and highlight a conserved role for cholinergic signaling in regulating rhythmic neural activity in the embryonic spinal cord.

A robust evaluation of TDP-43, poly GP, cellular pathology, and behavior in a AAV-C9ORF72 (G4C2)66 mouse model
The G4C2 hexanucleotide repeat expansion in C9ORF72 is the major genetic cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) (C9-ALS/FTD). Despite considerable efforts, the development of mouse models of C9-ALS/FTD useful for therapeutic development has proven challenging due to the intricate interplay of genetic and molecular factors underlying this neurodegenerative disorder, in addition to species differences. This study presents a robust investigation of the cellular pathophysiology and behavioral outcomes in a previously described AAV mouse model of C9-ALS expressing 66 G4C2 hexanucleotide repeats. Despite displaying key molecular ALS pathological markers including RNA foci, dipeptide repeat (DPR) protein aggregation, p62 positive stress granule formation as well as mild gliosis, the AAV-(G4C2)66 mouse model in this study exhibits negligible neuronal loss, no motor deficits, and functionally unimpaired TAR DNA-binding protein-43 (TDP-43). While our findings indicate and support that this is a robust and pharmacologically tractable model for investigating the molecular mechanisms and cellular consequences of (G4C2) repeat driven DPR pathology, it is not suitable for investigating the development of disease associated neurodegeneration, TDP-43 dysfunction, gliosis, and motor performance. Our findings underscore the complexity of ALS pathogenesis involving genetic mutations and protein dysregulation and highlight the need for more comprehensive model systems that reliably replicate the multifaceted cellular and behavioral aspects of C9-ALS.

Behavioral screening defines three molecular Parkinsonism subgroups in Drosophila
Parkinsonism is defined by motor dysfunction, but the specific upstream molecular causes of these clinical symptoms can vary widely. We hypothesize that these causes converge onto a limited number of core cellular pathways. To investigate this, we created a new collection of 24 genetically very well-controlled animal models of familial forms of parkinsonism. Using unbiased behavioral screening and machine learning we identified three clusters of mutants that converge on (1) mitochondrial function; (2) retromer/vesicle trafficking; and (3) proteostasis/autophagy. Genes within each cluster have a similar genetic interaction profile and compounds that target specific molecular pathways ameliorate dopaminergic neuron dysfunction in a cluster-specific manner. This suggests that familial parkinsonism can be stratified into three broad functional groups and our findings pave the way for targeted biomarker discovery and drug development.

NeuroSCAN: Exploring Neurodevelopment via Spatiotemporal Collation of Anatomical Networks
Volume electron microscopy (vEM) datasets such as those generated for connectome studies allow nanoscale quantifications and comparisons of the cell biological features underpinning circuit architectures. Quantifications of cell biological relationships in the connectome result in rich multidimensional datasets that benefit from data science approaches, including dimensionality reduction and integrated graphical representations of neuronal relationships. We developed NeuroSCAN, an online open-source platform that bridges sophisticated graph analytics from data science approaches with the underlying cell biological features in the connectome. We apply NeuroSCAN to a complete published record of C. elegans brain neuropils and demonstrate how these integrated representations of neuronal relationships facilitate comparisons across connectomes, catalyzing new insights on the structure-function of the circuits and their changes during development. NeuroSCAN is designed for intuitive examination and comparisons across connectomes, enabling synthesis of knowledge from high-level abstractions of neuronal relationships derived from data science techniques to the detailed identification of the cell biological features underpinning these abstractions.

Circuit firing homeostasis following synaptic perturbation ensures robust behavior
Homeostatic regulation of excitability and synaptic transmission ensures stable neural circuit output under changing conditions. We find that pre- or postsynaptic weakening of motor neuron (MN) to muscle glutamatergic transmission in Drosophila larva has little impact on locomotion, suggesting non-synaptic compensatory mechanisms. In vivo imaging of MN to muscle synaptic transmission and MN activity both show that synaptic weakening increases activity in tonic type Ib MNs, but not in the phasic type Is MN that innervate the same muscles. Additionally, an inhibitory class of pre-MNs that innervates type Ib-but not Is-MNs decreases activity. Our experiments suggest that weakening of MN evoked synaptic release onto the muscle is compensated for by an increase in MN firing due to a combined cell-autonomous increase in excitability and decreased inhibitory central drive. Selectivity for type Ib MNs may serve to restore tonic drive while absence of firing adjustment in the convergent Is MN can maintain the contraction wave dynamics needed for locomotion.

Exosomes can modulate the early hyperexcitability in cortical neurons with ASD-associated Shank3 mutation.
Shank3, a scaffolding protein, is critical for synaptic structure and function, particularly for the formation and maintenance of dendritic spines. Shank3 mutations are strongly implicated in autism spectrum disorder (ASD) and related neuropsychiatric conditions such as Phelan-McDermid Syndrome (PMS) also known as the 22q13.3 deletion syndrome. Previous work has recognized early hyperexcitability in cortical neurons derived from ASD patients with various gene mutations as a potential common endophenotype. In this study, we examined the effects of exosomes extracted from several cell types on the neurophysiological properties of cortical neurons derived from Shank3 (c.3679insG mutation) induced pluripotent stem cells (iPSCs). First, we sought to understand the implications of exosome-based intercellular communication on the neurophysiology of Shank3 mutant and control neurons by switching their respective exosomes. We found that while control neuron-derived exosomes do not change the neurophysiology of Shank3 neurons, the Shank3 neuron-derived exosomes transfer the early hyperexcitability and other ASD-related phenotypes to control neurons. Next, we also explored the therapeutic potential of mesenchymal stem cells (MSC) and iPSC-derived exosomes from healthy donors in the Shank3 cortical neurons. We demonstrate that both MSC and iPSC-derived exosomes rescue the early hyperexcitability and accelerated maturation of Shank3 neurons. Proteomic analysis of exosomes derived from Shank3 mutant and control neurons, as well as from exosomes derived from MSCs and iPSCs, revealed distinct protein cargoes that may cause changes in the neurophysiological properties of the recipient neurons. Our results hence provide novel insights into the pathophysiology of ASD emphasizing the importance of exosomes in intercellular communication and their potential to influence intrinsic and network properties of neurons. Moreover, our findings support the need for further exploration of exosome-based interventions as potential therapeutics for treating neurodevelopmental disorders.

Therapeutic suppression of Tubb4a rescues H-ABC leukodystrophy
Hypomyelination and atrophy of basal ganglia and cerebellum (H-ABC) is a rare leukodystrophy associated with causal variants in {beta}-tubulin 4A (TUBB4A). The recurring variant p.Asp249Asn (D249N) presents in infancy with dystonia, communication deficits, and loss of ambulation during the first decade of life. In this study, we characterized a genetic murine series (Tubb4aKO/KO, Tubb4aD249N/+, Tubb4aD249N/KO, and Tubb4aD249N/D249N) to demonstrate that disease severity correlates with the expression of mutant Tubb4a and relative preservation of WT tubulin. To further evaluate the translational potential of Tubb4a suppression as a therapy in H-ABC, we identified a well-tolerated Tubb4a-targeted antisense oligonucleotide (ASO) candidate that selectively reduces Tubb4a in vitro and in vivo. Notably, single intracerebroventricular (i.c.v.) administration of ASO in postnatal Tubb4aD249N/KO mice drastically extends its lifespan, improves motor phenotypes, and reduces seizures. Neuropathologically, ASO treatment in Tubb4aD249N/KO mice restores myelin and oligodendrocyte survival. Furthermore, in vivo visual evoked potential latencies recover in ASO-treated Tubb4aD249N/KO mice. This is the first preclinical proof-of-concept for Tubb4a suppression via ASO as a disease-modifying therapy for H-ABC.

Dissociating External and Internal Attentional Selection
Visual Working Memory (VWM) stores visual information for upcoming actions. Just as attention can shift externally towards relevant objects in the visual environment, attention can shift internally towards (i.e., prioritize) VWM content that is relevant for upcoming tasks. Internal and external attentional selection share a number of key neural and functional characteristics, which include their spatial organization: recent work has shown that spatial attention is directed towards the previous location of a prioritized memory item, similar to how a perceived stimulus is prioritized. Attending stimuli that are physically present is useful, as it enhances processing of the relevant visual input. When prioritizing items in memory, however, attending the prior stimulus location cannot serve this purpose, as there is no visual input to enhance. Here, we address this apparent contradiction which highlights the gaps in our understanding of the mechanisms underlying external and internal visual attention. In two EEG experiments, we compare location-specific sensory enhancement during the attentional selection of external (perceived) as compared to internal (memorized) stimuli. During both internal and external selection we observed a lateralization of alpha oscillations and gaze position bias toward the previous locations of prioritized items, confirming earlier findings that suggested an inherent spatial organization within VWM. Critically, using Rapid Invisible Frequency Tagging (RIFT), we show that sensory enhancement at the attended location is only observed during external attentional selection of (perceived) stimuli. No such location-specific sensory enhancement was observed during attentional selection of items in VWM. Furthermore, we found no clear relationship across trials between alpha lateralization and sensory enhancement (measured through RIFT) during external attention, suggesting that these two metrics indeed reflect distinct cognitive mechanisms. In sum, using a novel combination of EEG and RIFT, we demonstrate a fundamental distinction between the neural mechanisms underlying the selection of perceived and memorized objects. Both types of selection operate within a spatial reference frame, but only external selection modulates early sensory processing. Our findings suggest that the visual system is not vestigially recruiting existing mechanisms of external attention for prioritization in VWM, but is instead using space as an organizational principle to store and select items in VWM.

Vascular FLRT2 regulates venous-mediated angiogenic expansion and CNS barriergenesis
Veins have emerged as the origin of all other endothelial cell subtypes needed to expand vascular networks during developmental and pathological neoangiogenesis. Here, we uncover the significant role of the angioneurin Fibronectin Leucine Rich Transmembrane protein (FLRT) 2 in central nervous system (CNS) vascular development in the mouse. Early postnatal FLRT2 deletion reveals specific defects in retinal veins, impacting endothelial cell proliferation, sprouting and polarity that result in reduced tip cells at the vascular front. FLRT2 interacts with VE-cadherin and together with the endocytic adaptor protein Numb contribute to the modulation of adherens junction morphology in both retina and cerebral cortex in vivo. Utilizing expansion microscopy, we visualize the altered dynamic distribution of VE-cadherin in tissue of FLRT2 endothelial mutants. Additionally, FLRT2 in cortical vessels regulates the crosstalk between adherens and tight junctions, influencing blood-brain barrier development. Our findings position FLRT2 as a vein-specific crucial regulator of CNS vascular development.

NEBULA101: an open dataset for the study of language aptitude in behaviour, brain structure and function
This paper introduces the "NEBULA101 - Neuro-behavioural Understanding of Language Aptitude" dataset, which comprises behavioural and brain imaging data from 101 healthy adults to examine individual differences in language and cognition. Human language, a multifaceted behaviour, varies significantly among individuals, at different processing levels. Recent advances in cognitive science have embraced an integrated approach, combining behavioural and brain studies to explore these differences comprehensively. The NEBULA101 dataset offers brain structural, diffusion-weighted, task-based and resting-state MRI data, alongside extensive linguistic and non-linguistic behavioural measures to explore the complex interaction of language and cognition in a highly multilingual sample. By sharing this multimodal dataset, we hope to promote research on the neuroscience of language, cognition and multilingualism, enabling the field to deepen its understanding of the multivariate panorama of individual differences and ultimately contributing to open science.

Non-guided, Mobile, CBT-I-based Sleep Training in War-torn Ukraine: A Feasibility Study
ObjectivesTo study whether a mobile, unguided Cognitive Behavior Therapy-based Intervention for Sleep Disturbance, Sleep2 is feasible, acceptable, and reduces mental health/sleep disturbance symptoms among the Ukrainian population during the ongoing war.

MethodsA single-arm, open-label, uncontrolled pre-post evaluation study was conducted with 487 registered participants: 283 started, out of which 95 completed without an ambulatory heart rate (HR) sensor and 65 with. Assessments were conducted using online questionnaires and continuous objective measurements via HR sensors. Key outcome measures included sleep disturbance, insomnia, fear of sleep, anxiety, depression, PTSD, perceived stress, and somatic symptoms.

ResultsEngagement with the program was robust, achieving an 80.72% compliance rate, alongside high levels of feasibility and acceptance. Participants reported significant pre- post reductions in the severity of sleep disturbance (by 22.60%), insomnia (by 35.08%), fear of sleep (by 32.43%), anxiety (by 27.72%), depression (by 28.67%), PTSD (by 32.41%), somatic symptoms (by 24.52%), and perceived stress (by 17.90%), all with medium to high effect sizes. Objective sleep measurements showed a slight reduction in sleep onset latency.

ConclusionThe Sleep2Ukraine program demonstrated high feasibility and acceptance, with significant improvements in subjective sleep and mental health measures among participants. These findings demonstrate the potential of scalable mobile-based CBT-I interventions in war-torn regions with or without the instrument, based on the heart rate assessment.

Modeling Decision-Making Under Uncertainty with Qualitative Outcomes
Modeling decision-making under uncertainty typically relies on quantitative outcomes. Many decisions, however, are qualitative in nature, posing problems for traditional models. Here, we aimed to model uncertainty attitudes in decisions with qualitative outcomes. Participants made choices between certain outcomes and the chance for more favorable outcomes in quantitative (monetary) and qualitative (medical) modalities. Using computational modeling, we estimated the values participants assigned to qualitative outcomes and compared uncertainty attitudes across domains. Our model provided a good fit for the data, including quantitative estimates for qualitative outcomes. The model outperformed a utility function in quantitative decisions. Additionally, we found an association between ambiguity attitudes across domains. Results were replicated in an independent sample. We demonstrate the ability to extract quantitative measures from qualitative outcomes, leading to better estimation of subjective values. This allows for the characterization of individual behavior traits under a wide range of conditions.

Conditional Knockout of Striatal Gnal Produces Dystonia-like Motor Phenotypes
Loss-of-function mutations in GNAL have been linked to an adult-onset, isolated dystonia that is largely indistinguishable from idiopathic dystonia. GNAL encodes Golf, a heterotrimeric G-protein subunit with a defined molecular function to increase the production of the second messenger cAMP. Golf is abundant in the striatum, and is the only stimulatory G-protein in many cell types of the striatum. Due to the defined molecular signaling pathway and expression pattern of Golf, the clear genetic link to dystonia makes GNAL an exciting target to understand the pathological mechanisms of not only this genetic dystonia, but also the larger idiopathic disease. To better understand GNAL-linked dystonia, we generated a novel genetic mouse model that allows us to conditionally knock out Gnal in a site and time-specific manner. In the current study we used genetic or AAV based approaches to express Cre to knockout striatal Gnal in our novel Gnal fl/fl model. We then performed motor behavioral testing and ex vivo whole-cell patch clamp electrophysiology of striatal spiny projection neurons to interrogate how loss of Gnal leads to dystonia. Mice with conditional striatal knockout of Gnal show hindlimb clasping, other dystonia-like postures, less motor coordination, slowness, and torticollis as compared to age-matched controls. Furthermore, striatal spiny projection neurons show increased excitability in Gnal knockout animals. These exciting data are the first to report uninduced, overt dystonia in a mouse model of GNAL-linked dystonia, and directly correlate these with changes in spiny projection neuron electrophysiological properties. Our results show that adult loss of Gnal in the striatum leads to the development of dystonia, through homeostatic, paradoxical increases in spiny projection neuron excitability, and suggest that therapeutic strategies aimed at decreasing this hyperexcitable phenotype may provide symptomatic relief for patients with disease.

Developmental trajectory of thalamus topography during the late preterm and perinatal period in normal development, after premature birth and in congenital heart defects
The thalamus plays a critical role in neural circuit maturation and brain connectivity. It is well known to show a characteristic topographical organization of local and long-range connectivity, yet developmental changes in this topography remains incompletely understood. Our study aims to first validate the use of diffusion MRI for the topographic delineation of thalamic subdivisions (nuclei), to characterize thalamic topography during development and assess the impact of congenital heart defects (CHD) on thalamus development. We used local fiber orientation distribution functions, derived from diffusion MRI (dMRI) data, to subdivide the thalamus into seven clusters. We first evaluated the within-subject reproducibility of a dMRI based clustering method across 30 adults scan-rescan datasets using K-means clustering, achieving reproducible segmentation of the thalamus into seven parts. This was applied to a large developmental cohort comprising normally developing infants, preterm-born newborns ranging from 29.2 to 48.7 corrected gestational weeks, as well as one case of postmortem fetal specimen. Cluster volumes were analyzed as a function of age using multivariate linear regression, while differences in the cluster volumes between control subjects and newborns with CHD were analyzed with a variance analysis, controlling for sex, age at MRI scan. The clustering on average had a within-subject overlap of 0.811 (Dice overlap metric). While absolute thalamus volumes in-creased with age, their relative volumes remained stable in the studied developmental period. CHD infants shown reduced absolute volumes in six of the seven thalamic nuclei, with significant increasing in the relative volume of the cluster overlapping with the mediodorsal nucleus. While the perinatal period comprises rapid developmental events including the maturation of white matter, the topography of thalamic circuitry remains stable. Our study highlights alterations in thalamic topology and potential impacts on brain connectivity in CHD infants. By leveraging local diffusion properties from diffusion MRI, our validated segmentation technique offers a robust, data-centric approach to thalamic delineation.

Reconfiguration of Functional Brain Hierarchy in Schizophrenia
The multidimensional nature of schizophrenia requires a comprehensive exploration of the functional and structural brain networks. While prior research has provided valuable insights into these aspects, our study goes a step further to investigate the reconfiguration of the hierarchy of brain dynamics, which can help understand how brain regions interact and coordinate in schizophrenia. We applied an innovative thermodynamic framework, which allows for a quantification of the degree of functional hierarchical organization by analysing resting state fMRI-data. Our findings reveal increased hierarchical organization at the whole-brain level and within specific resting-state networks in individuals with schizophrenia, which correlated with negative symptoms, positive formal thought disorder and apathy. Moreover, using a machine learning approach, we showed that hierarchy measures allow a robust diagnostic separation between healthy controls and schizophrenia patients. Thus, our findings provide new insights into the nature of functional connectivity anomalies in schizophrenia, suggesting that they could be caused by the breakdown of the functional orchestration of brain dynamics.

Non-spatial hippocampal behavioral timescale synaptic plasticity during working memory is gated by entorhinal inputs
Behavioral timescale synaptic plasticity (BTSP) is a form of synaptic potentiation where the occurrence of a single large plateau potential in CA1 hippocampal neurons leads to the formation of reliable place fields during spatial learning tasks. We asked whether BTSP could also be a plasticity mechanism for generation of non-spatial responses in the hippocampus and what roles the medial and lateral entorhinal cortex (MEC and LEC) play in driving non-spatial BTSP. By performing simultaneous calcium imaging of dorsal CA1 neurons and chemogenetic inhibition of LEC or MEC while mice performed an olfactory working memory task, we discovered BTSP-like events which formed stable odor-specific fields. Critically, the success rate of calcium events generating a significant odor-field increased with event amplitude, and large events exhibited asymmetrical formation with the newly formed odor-fields preceding the timepoint of their induction event. We found that MEC and LEC play distinct roles in modulating BTSP: MEC inhibition reduced the frequency of large calcium events, while LEC inhibition reduced the success rate of odor-field generation. Using two-photon calcium imaging of LEC and MEC temporammonic axons projecting to CA1, we found that LEC projections to CA1 were strongly odor selective even early in task learning, while MEC projection odor-selectivity increased with task learning but remained weaker than LEC. Finally, we found that LEC and MEC inhibition both slowed representational drift of odor representations in CA1 across 48 hours. Altogether, odor-specific information from LEC and strong odor-timed activity from MEC are crucial for driving BTSP in CA1, which is a synaptic plasticity mechanism for generation of both spatial and non-spatial responses in the hippocampus that may play a role in explaining representational drift and one-shot learning of non-spatial information.

Differential encoding of mammalian proprioception by voltage-gated sodium channels
Animals that require purposeful movement for survival are endowed with mechanosensory neurons called proprioceptors that provide essential sensory feedback from muscles and joints to spinal cord circuits, which modulates motor output. Despite the essential nature of proprioceptive signaling in daily life, the mechanisms governing proprioceptor activity are poorly understood. Here, we have identified distinct and nonredundant roles for two voltage-gated sodium channels (Navs), Nav1.1 and Nav1.6, in mammalian proprioception. Deletion of Nav1.6 in somatosensory neurons (Nav1.6cKO mice) causes severe motor deficits accompanied by complete loss of proprioceptive transmission, which contrasts with our previous findings using similar mouse models to target NaV1.1 (Nav1.1cKO). In Nav1.6cKO animals, loss of proprioceptive feedback caused non-cell-autonomous impairments in proprioceptor end-organs and skeletal muscle that were absent in Nav1.1cKO mice. We attribute the differential contribution of Nav1.1 and Nav1.6 in proprioceptor function to distinct cellular localization patterns. Collectively, these data provide the first evidence that Nav subtypes uniquely shape neurotransmission within a somatosensory modality.

Cell type-specific impact of aging and Alzheimer disease on hippocampal CA1 perforant path input
The perforant path (PP) carries direct inputs from entorhinal cortex to CA1 pyramidal neurons (PNs), with an impact dependent on PN position across transverse (CA1a/CA1c) and radial (superficial/deep) axes. It remains unclear how aging and Alzheimer disease (AD) affect PP input, despite its critical role in memory and early AD. Applying ex vivo recordings and two-photon microscopy in slices from mice up to 30 months old, we interrogated PP responses across PN subpopulations and compared them to Schaffer collateral and intrinsic excitability changes. We found that aging uniquely impacts PP excitatory responses, abolishing transverse and radial differences via a mechanism independent of presynaptic and membrane excitability change. This is amplified in aged 3xTg-AD mice, with further weakening of PP inputs to CA1a superficial PNs associated with distal dendritic spine loss. This demonstrates a unique feature of aging related circuit dysfunction, with mechanistic implications related to memory impairment and synaptic vulnerability.

Neuronal heterogeneity in the medial septum and diagonal band of Broca: classes and continua
The medial septum and diagonal band of Broca is known for its diverse populations of cholinergic, GABAergic, and glutamatergic neurons and their behaviorally relevant functions. Behavioral studies and cell-specific manipulations within this region have underscored its involvement in a diverse array of mouse behaviors, implying the presence of a more intricate and complex cellular landscape than previously acknowledged. In this study, we employed single-cell RNA sequencing to thoroughly characterize the heterogeneity of septal neurons. Our findings confirmed previously known neuronal classes and uncovered previously undescribed subclasses, as well as expression gradients. We identified transcriptomic identities of molecularly defined cell populations and validated the expression of cell type-specific marker genes using spatial transcriptomic datasets, mapping distinct patterns of cell distribution. Taken together, our analyses provide a comprehensive description of MSDB cell type diversity and novel marker genes to investigate the intricate neuronal composition of the medial septal region.

A novel baseline-effect shift tracking model for more sensitive detection of differences in the effects of closely related dopamine transporter inhibitor/ sigma receptor antagonist drug combinations on psychostimulant use.
Background: For the purpose of improving the ability to distinguish the activity of closely related drugs on psychostimulant use to enable more specific drug effect characterization, we have developed a new model termed the baseline-effect shift tracking (BEST) model. BEST compares/contrasts the baseline-drug activity relationship(s). Aim: To compare the current model to our BEST model to determine which was more effective in distinguishing the effects of combinations of a dopamine transporter inhibitor (methylphenidate, MPD) and selective sigma1 (BD1063) and non-selective (BD1008) sigma receptor antagonists on cocaine consumption. Methods: Male Sprague Dawley rats were trained to self-administer cocaine (n = 9, 0.32 mg/kg/infusion) or sucrose pellets (n = 6, 20 mg pellets/delivery). We determined the effects for cocaine/sucrose of combinations of MPD (1 mg/kg i.p) and 1) BD1063 (0, 3.2, 10 mg/kg i.p), and 2) BD1008 (0, 3.2, 10 mg/kg i.p) on a) consumption at zero price (Q0), and b) essential value (eValue, demand elasticity) estimated using behavioral economic analysis of within-session demand curves, and c) the total intake under the price response curve (TIPR). We compared the models using ANOVA/ regression analysis. Results: The current model did not detect any differences in the effects of these drug combinations on cocaine/ sucrose taking behavior. For cocaine, but not for sucrose, the BEST model detected differences in the effects of these drug combinations on TIPR in subjects with higher baseline activity. Conclusion: BEST model (with TIPR analysis) is more sensitive than the current models in differentiating the drug effects on cocaine consumption.

Auditory perception and neural representation of temporal fine structure are impaired by age but not by cochlear synaptopathy
Age-related hearing loss is a complex phenomenon. The earliest-onset degenerative event is the gradual loss of neural connections between cochlea and auditory brainstem. To probe for perceptual deficits that might arise from this loss, cochlear synaptopathy was induced pharmacologically in young-adult gerbils which were then tested in a challenging listening task for the perception of temporal fine structure. Treated gerbils behaved no differently than normal-hearing, young-adult animals. In contrast, old gerbils, which typically express many cochlear and central-neural pathologies, showed impaired perception. To probe for the underlying mechanisms, single-unit responses were obtained from the auditory nerve to the same test stimuli. Responses from old gerbils showed no impairment in temporal locking to the stimulus fine structure. However, responses were significantly more driven by slower temporal fluctuations of the stimulus envelope, suggesting that the central auditory system may be unable to extract the relevant information for discrimination from such altered inputs.

The ERGtools2 package: A Toolset for Processing and Analysing Visual Electrophysiology Data
Purpose: To introduce and demonstrate the functionality of ERGtools2, an open-source R package for processing and analysing of visual electrophysiology data, with a focus on data integrity, shareability and long-term preservation. Methods: A dataset comprising Electroretinogram(ERG) recordings from both eyes of C57Bl/6J mice, subjected to standard ISCEV stimuli, was used to present the functionality of ERGtools2. ERGtools2 stores and organizes all recordings, metadata, and measurement information from individual examination in a single object, maintaining raw data throughout the analysis process. Results: A standard workflow is presented exemplifying how ERGtools2 can be used to efficiently import, preprocess and analyse ERG data. Following this workflow basic ERG measurements like a and B-wave amplitudes and visualisation of a single exam as well as group statistics are obtained. Moreover, special use cases are described, including for the handling of noisy data and the storage of data in the HDF5 format to ensure long-term preservation and accessibility. ERGtools2 also provides a graphical interface. Conclusions: ERGtools2 provides a comprehensive, flexible, and device-independent solution for visual electrophysiology data analysis. Its emphasis on maintaining raw data integrity, combined with advanced processing and analysis capabilities, makes it a useful tool research and potentially also clinical applications. The open-source nature and the use of open data formats promote reproducibility and data sharing in visual neurosciences. Translational Relevance: ERGtools2 allows for sophisticated preclinical and clinical visual electrophysiology analyses. This will be helpful, for instance, in the context optogenetic vision-restoring, where signal shapes and amplitudes may be substantially different from normal vision.

EEG During Dynamic Facial Emotion Processing Reveals Neural Activity Patterns Associated with Autistic Traits in Children
Altered brain connectivity and atypical neural oscillations have been observed in autism, yet their relationship with autistic traits in non-clinical populations remains underexplored. Here, we employ electroencephalography (EEG) to examine functional connectivity, oscillatory power, and broadband aperiodic activity during a dynamic facial emotion processing (FEP) task in 101 typically developing children aged 4-12 years. We investigate associations between these electrophysiological measures of brain dynamics and autistic traits as assessed by the Social Responsiveness Scale, 2nd Edition (SRS-2). Our results revealed that increased FEP-related connectivity across theta (4-7 Hz) and beta (13-30 Hz) frequencies correlated positively with higher SRS-2 scores, predominantly in right-lateralized (theta) and bilateral (beta) cortical networks. Additionally, a steeper 1/f-like aperiodic slope (spectral exponent) across fronto-central electrodes was associated with higher SRS-2 scores. Greater aperiodic-adjusted theta and alpha oscillatory power further correlated with both higher SRS-2 scores and steeper aperiodic slopes. These findings underscore important links between FEP-related brain dynamics and autistic traits in typically developing children. Future work could extend these findings to assess these EEG-derived markers as potential mechanisms underlying behavioural difficulties in autism.