PaperPlayer biorxiv neuroscience

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.12.038117v1?rss=1 Authors: Katti, H., Arun, S. Abstract: Reading distorted letters is easy for us but so challenging for machine vision that it is used on websites as CAPTCHAs (Completely Automated Public Turing test to tell Computers and Humans Apart). How does our brain solve this problem? One solution to have neurons invariant to letter distortions but selective for letter combinations. Another is for neurons to separately encode letter distortions and combinations. Here, we provide evidence for the latter using neural recordings in the monkey inferior temporal cortex. Neurons encoded letter distortions as a product of letter and distortion tuning, and letter combinations as a sum of letters. These rules were sufficient for perfect CAPTCHA decoding, and present in neural networks trained for letter recognition. Thus, a separable neural code enables efficient reading. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.11.021915v1?rss=1 Authors: Zhu, F., Wang, W., Ma, Q., Yang, Z., Ju, Y., Fan, Y., Guo, R., Wang, Q., Mu, X., Zhao, B., Gao, Y., He, X., Gao, F., Qian, L., Chen, C., Chen, Y., Gao, C., Ma, X.-c. Abstract: Objective: Gut microbiota dysbiosis and aberrant gut-brain functional modules including short-chain fatty acid (SCFA) production and long-lasting immune activation (IA) are presented in schizophrenia. Given the key roles of gut microbiota and SCFA in shaping immunity, we propose that dysbiosis-induced SCFA upregulation could contribute to IA and behavioral symptoms in schizophrenia. Design: Gut microbiota, SCFA, and IA biomarkers were compared between schizophrenic patients and healthy controls. The roles of SCFA in schizophrenia-related IA were analyzed in cultured peripheral blood mononuclear cells (PBMCs) and a mouse model of schizophrenia. The effects of SCFAs on schizophrenia-related phenotypes were analyzed in both human and mouse. Results: Both microbial-derived SCFA and SCFA-producing bacteria were elevated in the guts of schizophrenic patients, and this increased SCFA production in gut was associated with IA in schizophrenia. The microbiome signature underpinning schizophrenia-related IA includes increased diversity and increased SCFA-producing bacteria and inflammation-associated bacteria. The impact of SCFAs on immune responses of cultured PBMC depend on the diagnosis and IA status of donors. Small-molecule serum filtrates from immune-activated schizophrenic patients increased the inflammatory response of PBMCs from healthy volunteers, which can be enhanced and attenuated by SCFAs supplementation and inhibition of SCFA signaling, respectively. Chronically elevated SCFAs in adolescence induced neuroinflammation and schizophrenia-like behaviors in adult mice. Moreover, chronically elevated SCFAs in adult mice prenatally exposed to IA potentiated their expression of schizophrenia-like behaviors. Conclusion: microbiota-derived SCFAs are important mediators of dysregulated gut-brain axis and participant in pathogenesis via enhance IA in schizophrenia. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.12.038141v1?rss=1 Authors: Fouyssac, M., Puaud, M., Ducret, E., Marti-Prats, L., Vanhille, N., Ansquer, S., Zhang, X., Belin-Rauscent, A., Giuliano, C., Houeto, J.-L., Everitt, B., Belin, D. Abstract: The transition from controlled drug use to drug addiction depends on an interaction between a vulnerable individual, their environment and a drug. However, the determining factors of this interaction remain elusive. We show in rats that the environment influences the acquisition of drug intake through its effect on behavioral markers of resilience to addiction. In contrast, the development of both compulsive cocaine and alcohol intake is facilitated by the experiential factors associated with the initiation of drug taking in a negative, deprived, state occasioned by the contrast between enriched housing conditions and a relatively impoverished drug-taking setting. Similarly, the acquisition of alcohol drinking as a coping strategy promotes the development of compulsive intake. These data demonstrate that addiction vulnerability lies in environmentally determined experiential factors. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.12.038356v1?rss=1 Authors: Mohebi, A., Oweiss, K. G. Abstract: Orienting movements are essential to sensory-guided reward-seeking behaviors. Prefrontal cortex (PFC) is believed to exert top-down control over a range of goal-directed behaviors and is hypothesized to bias sensory-guided movements. However, the nature of PFC involvement in controlling sensory-guided orienting behaviors has remained largely unknown. Here, we trained rats on a delayed two-alternative forced-choice task requiring them to hold an orienting decision in working memory before execution is cued. Medial PFC (mPFC) Inactivation using either Muscimol or optogenetics impaired choice behavior. However, optogenetic impairment depended on the specific trial epoch during which inactivation took place. In particular, we found a lateralized role for mPFC during the presentation of instruction cues but this role became bilateral when inactivation occurred later in the delay period. Electrophysiological recording of multiple single-unit activity further provided evidence that this lateralized selectivity is cell-type specific. Our results suggest a previously unknown role of mPFC in mediating sensory-guided representation of orienting behavior and a potentially distinct cell-type specific role in shaping such representation across time. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.036632v1?rss=1 Authors: Majka, P., Bednarek, S., Chan, J. M. M., Jermakow, N., Liu, C., Saworska, G., Worthy, K. H., Silva, A. C., Wojcik, D. K., Rosa, M. G. P. Abstract: The rapid adoption of marmosets in neuroscience has created a demand for three dimensional (3D) atlases of the brain of this species to facilitate data integration in a common reference space. We report on a new open access template of the marmoset cortex (the Nencki-Monash, or NM template), representing a morphological average of 20 brains of young adult individuals, obtained by 3D reconstructions generated from Nissl-stained serial sections. The method used to generate the template takes into account morphological features of the individual brains, as well as the borders of clearly defined cytoarchitectural areas. This has resulted in a resource which allows direct estimates of the most likely coordinates of each cortical area, as well as quantification of the margins of error involved in assigning voxels to areas, and preserves quantitative information about the laminar structure of the cortex. We provide spatial transformations between the NM and other available marmoset brain templates, thus enabling integration with magnetic resonance imaging (MRI) and tracer-based connectivity data. The NM template combines some of the main advantages of histology-based atlases (e.g. information about the cytoarchitectural structure) with features more commonly associated with MRI-based templates (isotropic nature of the dataset, and probabilistic analyses). The underlying workflow may be found useful in the future development of brain atlases that incorporate information about the variability of areas in species for which it may be impractical to ensure homogeneity of the sample in terms of age, sex and genetic background. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.13.038836v1?rss=1 Authors: Siuda-Krzywicka, K., Witzel, C., Bartolomeo, P., Cohen, L. Abstract: Naming a color can be understood as an act of categorization, i.e. identifying it as a member of a category of colors that are referred to by the same name. But are naming and categorization equivalent cognitive processes, and consequently rely on the same neural substrates? Here, we used task and resting-state fMRI, as well as behavioral measures to identify functional brain networks that are modulated by naming and categorization of colors. Color naming and categorization performance differentially modulated resting-state connectivity networks spanning from the color-sensitive regions in the ventro-occipital cortex. Color naming response times were correlated with the connectivity between the left posterior Color region, the left medial temporal gyrus, and the left angular gyrus; whereas color categorization involved the connectivity between the bilateral posterior Color regions, the left frontal, right temporal and bilateral parietal areas. The networks supporting naming and categorization did not overlap, suggesting that the two processes rely on different neural mechanisms. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.13.035386v1?rss=1 Authors: Thrupp, N., Sala Frigerio, C., Wolfs, L., Skene, N. G., Poovathingal, S., Fourne, Y., Matthews, P. M., Theys, T., Mancuso, R., de Strooper, B., Fiers, M. Abstract: Single nucleus RNA-Seq (snRNA-Seq) methods are used as an alternative to single cell RNA-Seq methods, as they allow transcriptomic profiling of frozen tissue. However, it is unclear whether snRNA-Seq is able to detect cellular state. Indeed, snRNA-Seq analyses of human brain samples have failed to detect a consistent microglial activation signature in Alzheimer's Disease. A comparison of microglia from single cells and single nuclei of four human subjects reveals that ~1% of genes is depleted in nuclei compared to whole cells. This small population contains 18% of genes previously implicated in microglial activation, including APOE, CST3, FTL, SPP1, and CD74. We confirm our findings across multiple previous single nucleus and single cell studies. Given the low sensitivity of snRNA-Seq to this population of activation genes, we conclude that snRNA-Seq is not suited to detecting cellular activation in microglia in human disease. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.035758v1?rss=1 Authors: Petridi, S., Middleton, C. A., Covill, L., Elliott, C., Fellgett, A., Ugbode, C. Abstract: LRRK2 mutations cause Parkinson's, but the molecular link from increased kinase activity to pathological neurodegeneration remains undetermined. Previous in vitro assays indicate that LRRK2 substrates include at least 8 Rab GTPases. We have now examined this hypothesis in vivo in a functional, electroretinogram screen, expressing each Rab with/without LRRK2-G2019S in selected Drosophila dopaminergic neurons. Our screen discriminated Rab10 from Rab3. The strongest Rab/LRRK2-G2019S interaction is with Rab10; the weakest with Rab3. Rab10is expressed in dopaminergic neurons controlling vision where Rab3 is undetectable. Thus, anatomical and physiological patterns of Rab10 are related. We conclude that Rab10 is a valid substrate of LRRK2 in dopaminergic neurons in vivo. We propose that variations in Rab expression contribute to differences in the rate of neurodegeneration recorded in different dopaminergic nuclei in Parkinson's. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.035980v1?rss=1 Authors: Deng, X., Chen, S., Sosa, M., Karlsson, M. P., Wei, X.-X., Frank, L. M. Abstract: Humans have the ability to retrieve memories with various degrees of specificity, and recent advances in reinforcement learning have identified benefits to learning when past experience is represented at different levels of temporal abstraction. How this flexibility might be implemented in the brain remains unclear. We analyzed the temporal organization of rat hippocampal population spiking to identify potential substrates for temporally flexible representations. We examined activity both during locomotion and during memory-retrieval-associated population events known as sharp wave-ripples (SWRs). We found that spiking during SWRs is rhythmically organized with higher event-to-event variability than spiking during locomotion-associated population events. Decoding analyses using clusterless methods further suggest that similar spatial experience can be replayed in multiple SWRs, each time with a different rhythmic structure whose periodicity is sampled from a lognormal distribution. This variability is preserved despite the decline in SWR rates that occurs as environments become more familiar: in more familiar environments the width of the lognormal distribution increases, further enhancing the range of temporal variability. We hypothesize that the variability in temporal organization of hippocampal spiking provides a mechanism for retrieving remembered experiences with various degrees of specificity. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.12.036392v1?rss=1 Authors: Wu, Y., Zeng, J., Pluimer, B., Dong, S., Xie, X., Guo, X., Liang, X., Feng, S., Wu, H., Yan, Y., Chen, J.-F., Maria, N. S., Ma, Q., Gomez-Pinilla, F., Zhao, Z. Abstract: Introduction: Traumatic brain injury (TBI) is considered as the most robust environmental risk factor for Alzheimer's disease (AD). Besides direct neuronal injury and neuroinflammation, vascular impairment is also a hallmark event of the pathological cascade after TBI. However, the vascular connection between TBI and subsequent AD pathogenesis remains underexplored. Methods: We established a closed-head mild TBI (mTBI) model in mice with controlled cortical impact, and examined the time courses of microvascular injury, blood-brain barrier (BBB) dysfunction, gliosis and motor function impairment in wild type C57BL/6 mice. We also determined brain clearance of {beta}-amyloid, as well as amyloid pathology and cognitive functions after mTBI in the 5xFAD mouse model of AD. Results: mTBI induced microvascular injury with BBB breakdown, pericyte loss and cerebral blood flow reduction in mice, which preceded gliosis. mTBI also impaired brain amyloid clearance via the vascular pathways. More importantly, mTBI accelerated amyloid pathology and cognitive impairment in the 5xFAD mice. Discussion: Our data demonstrated that microvascular injury plays a key role in the pathogenesis of AD after mTBI. Therefore, restoring vascular functions might be beneficial for patients with mTBI, and potentially reduce the risk of developing AD Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.036202v1?rss=1 Authors: Köbe, T., Pichet Binette, A., Vogel, J. W., Meyer, P.-F., Breitner, J. C., Poirier, J., Villeneuve, S. Abstract: Introduction: Cross-sectional studies suggest that cardiovascular risk factors and Alzheimer's disease (AD) biomarkers are associated with abnormal brain resting-state functional connectivity in aging and AD; however, evidence is missing regarding longitudinal changes in functional connectivity. In this study, we investigate whether cholesterol levels and blood pressure are associated with changes in functional connectivity over time in asymptomatic individuals at risk for AD. The analyses were repeated with cerebral {beta}-amyloid (A{beta}) and tau deposition in a subset of the participants. Methods: The study sample included 247 cognitively unimpaired individuals (185 women/ 62 men; mean [SD] age of 63 [5.3] years) of the PREVENT-AD cohort with a parental or multiple-sibling history of sporadic AD. Plasma total-, HDL-, and LDL-cholesterol and systolic and diastolic blood pressure were measured at baseline. Global brain functional connectivity, and connectivity from canonical functional networks, were computed from resting-state functional MRI obtained at baseline and up to four years of annual follow-ups, using a predefined functional parcellation. A subset of participants underwent tau-PET ([18F]Flortaucipir) and A{beta}-PET ([18F]NAV4694). Vascular and AD measures were examined as predictors of brain functional connectivity changes in linear mixed-effects models. Results: Higher total-cholesterol and LDL-cholesterol levels were associated with greater reduction of functional connectivity in the default-mode network over time. In addition, while overall whole-brain functional connectivity showed an increase over time across the entire sample higher diastolic blood pressure was associated with reduction in whole-brain functional connectivity. The associations were similar when the analyses were repeated using two other functional brain parcellations. The findings with total-cholesterol and diastolic blood pressure were also similar but attenuated when performed in a subsample of participants with PET (n=91), whereas AD biomarkers were not associated with changes in functional connectivity over time in this subsample. Conclusion: These findings provide evidence that vascular burden is associated with a decrease in brain functional connectivity over time in older adults with elevated risk for AD. The impact of vascular risk factors on functional brain changes might precede AD pathology-related changes. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.996116v1?rss=1 Authors: Bollimunta, A., Santacruz, S. R., Eaton, R. W., Xu, P. S., Morrison, J. H., Moxon, K. A., Carmena, J. M., Nassi, J. J. Abstract: A major effort is now underway across the brain sciences to identify, characterize and manipulate mesoscale neural circuits in order to elucidate the mechanisms underlying sensory perception, cognition and behavior. Optical imaging technologies, in conjunction with genetically encoded sensors and actuators, serve as important tools toward these goals, allowing access to large-scale genetically defined neuronal populations. In particular, one-photon miniature microscopes, coupled with genetically encoded calcium indicators and microendoscopic gradient-refractive index (GRIN) lenses, enable unprecedented readout of neural circuit dynamics in cortical and deep subcortical brain regions during active behavior in rodents. This has already led to breakthrough discoveries across a wide array of rodent brain regions and behaviors. However, in order to study the neural circuit mechanisms underlying more complex and clinically relevant human behaviors and cognitive functions, it is crucial to translate this technology to non-human primates. Here, we describe the first successful application of this technology in the rhesus macaque. We identified a viral strategy for robust expression of GCaMP, optimized a surgical protocol for microendoscope GRIN lens insertion, and created a chronic cranial chamber and lens mounting system for imaging in gyral cortex. Using these methods, we demonstrate the ability to perform plug-and-play, head-mounted recordings of cellular-resolution calcium dynamics from over 100 genetically-targeted neurons simultaneously in dorsal premotor cortex while the macaque performs a naturalistic motor reach task with the head unrestrained and freely moving. The recorded population of neurons exhibited calcium dynamics selective to the direction of reach, which we show can be used to decode the animal's trial-by-trial motor behavior. Recordings were stable over several months, allowing us to longitudinally track large populations of individual neurons and monitor their relationship to motor behavior over time. Finally, we demonstrate the ability to conduct simultaneous, multi-site imaging in bilateral dorsal premotor cortices, offering an opportunity to study distributed networks underlying complex behavior and cognition. Together, this work establishes head-mounted microendoscopic calcium imaging in macaque as a powerful new approach for studying the neural circuit mechanisms underlying complex and clinically relevant behaviors, and promises to greatly advance our understanding of human brain function, as well as its dysfunction in neurological disease. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.036400v1?rss=1 Authors: Swartz, E. W., Shintani, G., Wan, J., Maffei, J. S., Wang, S. H., Miller, B. L., Havton, L. A., Coppola, G. Abstract: The failure of the neuromuscular junction (NMJ) is a key component of degenerative neuromuscular disease, yet how NMJs degenerate in disease is unclear. Human induced pluripotent stem cells (hiPSCs) offer the ability to model disease via differentiation toward affected cell types, however, the re-creation of an in vitro neuromuscular system has proven challenging. Here we present a scalable, all-hiPSC-derived co-culture system composed of independently derived spinal motor neurons (MNs) and skeletal myotubes (sKM). In a model of C9orf72-associated disease, co-cultures form functional NMJs that can be manipulated through optical stimulation, eliciting muscle contraction and measurable calcium flux in innervated sKM. Furthermore, co-cultures grown on multi-electrode arrays (MEAs) permit the pharmacological interrogation of neuromuscular physiology. Utilization of this co-culture model as a tunable, patient-derived system may offer significant insights into NMJ formation, maturation, repair, or pathogenic mechanisms that underlie NMJ dysfunction in disease. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.036244v1?rss=1 Authors: Sachdeva, P. S., Livezey, J. A., Dougherty, M. E., Gu, B.-M., Berke, J. D., Bouchard, K. E. Abstract: A central goal of systems neuroscience is to understand the relationships amongst constituent units in neural populations and their modulation by external factors using high-dimensional and stochastic neural recordings. Statistical models, particularly parametric models, play an instrumental role in accomplishing this goal, because their fitted parameters can provide insight into the underlying biological processes that generated the data. However, extracting conclusions from a parametric model requires that it is fit using an inference procedure capable of selecting the correct parameters and properly estimating their values. Traditional approaches to parameter inference have been shown to suffer from failures in both selection and estimation. Recent development of algorithms that ameliorate these deficiencies raises the question of whether past work relying on such inference procedures have produced inaccurate systems neuroscience models, thereby impairing their interpretation. Here, we used the Union of Intersections, a statistical inference framework capable of state-of-the-art selection and estimation performance, to fit functional coupling, encoding, and decoding models across a battery of neural datasets. We found that, compared to baseline procedures, UoI inferred models with increased sparsity, improved stability, and qualitatively different parameter distributions, while maintaining predictive performance across recording modality, brain region, and task. Specifically, we obtained highly sparse functional coupling networks with substantially different community structure, more parsimonious encoding models, and decoding models that rely on fewer single-units. Together, these results demonstrate that accurate parameter inference reshapes interpretation in diverse neuroscience contexts. The ubiquity of model-based data-driven discovery in biology suggests that analogous results would be seen in other fields. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.11.037200v1?rss=1 Authors: Lustberg, D., Tillage, R. P., Bai, Y., Pruitt, M., Liles, L. C., Weinshenker, D. Abstract: Rationale: In rodents, exposure to novel environments elicits initial anxiety-like behavior (neophobia) followed by intense exploration (neophilia) that gradually subsides as the environment becomes familiar. Thus, innate novelty-induced behaviors are useful indices of anxiety and motivation in animal models of psychiatric disease. Noradrenergic neurons are activated by novelty and implicated in exploratory and anxiety-like responses, but the role of norepinephrine (NE) in neophobia has not been clearly delineated. Objective: We sought to define the role of central NE transmission in neophilic and neophobic behaviors. Methods: We assessed dopamine {beta}-hydroxylase knockout (Dbh -/-) mice lacking NE and their NE-competent (Dbh +/-) littermate controls in neophilic (novelty-induced locomotion; NIL) and neophobic (novelty-suppressed feeding; NSF) behavioral tests with subsequent quantification of brain-wide c-fos induction. We complimented the gene knockout approach with pharmacological interventions. Results: Dbh -/- mice exhibited blunted locomotor responses in the NIL task and completely lacked neophobia in the NSF test. Neophobia was rescued in Dbh -/- mice by acute pharmacological restoration of central NE with the synthetic precursor L-3,4-dihydroxyphenylserine (DOPS), and attenuated in control mice by the inhibitory 2-adrenergic autoreceptor agonist guanfacine. Following either NSF or NIL, Dbh -/- mice demonstrated reduced c-fos in the anterior cingulate cortex, medial septum, ventral hippocampus, bed nucleus of the stria terminalis, and basolateral amygdala. Conclusion: These findings indicate that central NE signaling is required for the expression of both neophilic and neophobic behaviors. Further, we describe a putative noradrenergic novelty network as a potential therapeutic target for treating anxiety and substance abuse disorders. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.11.036954v1?rss=1 Authors: Singh, S., Tench, C., Tanasescu, R., Constantinescu, C. Abstract: The purpose of this coordinate based meta-analysis (CBMA) was to summarise the available evidence related to regional grey matter (GM) changes in patients with multiple sclerosis (MS) and clinically isolated syndrome (CIS). CBMA is a way to find the consistent results across multiple independent studies that are otherwise not easily comparable due to methodological differences. The coordinate based random effect size (CBRES) meta-analysis method utilizes the reported coordinates (foci of the clusters of GM loss) and Z score standardised by number of subjects, controlling type I error rate by false cluster discovery rate (FCDR). Thirty-four published articles reporting forty-five independent studies using voxel-based morphometry (VBM) for the assessment of GM atrophy between MS or CIS patients and healthy controls were identified from electronic databases. The primary meta-analysis identified clusters of spatially consistent cross-study reporting of GM atrophy; subgroup analyses and meta-regression were also performed. This meta-analysis demonstrates consistent areas of GM loss in MS or CIS, in the form of significant clusters. Some clusters also demonstrate correlation with disease duration. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.11.037333v1?rss=1 Authors: Timaeus, L., Geid, L., Sancer, G., Wernet, M. F., Hummel, T. Abstract: One hallmark of the visual system is the strict retinotopic organization from the periphery towards the central brain, spanning multiple layers of synaptic integration. Recent Drosophila studies on the computation of distinct visual features have shown that retinotopic representation is often lost beyond the optic lobes, due to convergence of columnar neuron types onto optic glomeruli. Nevertheless, functional imaging revealed a spatially accurate representation of visual cues in the central complex (CX), raising the question how this is implemented on a circuit level. By characterizing the afferents to a specific visual glomerulus, the anterior optic tubercle (AOTU), we discovered a spatial segregation of topographic versus non-topographic projections from molecularly distinct classes of medulla projection neurons (medullo-tubercular, or MeTu neurons). Distinct classes of topographic versus non-topographic MeTus form parallel channels, terminating in separate AOTU domains. Both types then synapse onto separate matching topographic fields of tubercular-bulbar (TuBu) neurons which relay visual information towards the dendritic fields of central complex ring neurons in the bulb neuropil, where distinct bulb sectors correspond to a distinct ring domain in the ellipsoid body. Hence, peripheral topography is maintained due to stereotypic circuitry within each TuBu class, providing the structural basis for spatial representation of visual information in the central complex. Together with previous data showing rough topography of lobula projections to a different AOTU subunit, our results further highlight the AOTUs role as a prominent relay station for spatial information from the retina to the central brain. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.11.037127v1?rss=1 Authors: Greene, M. R., Hansen, B. C. Abstract: Human scene categorization is characterized by its remarkable speed. While many visual and conceptual features have been linked to this ability, significant correlations exist between feature spaces, impeding our ability to determine their relative contributions to scene categorization. Here, we employed a whitening transformation to decorrelate a variety of visual and conceptual features and assess the time course of their unique contributions to scene categorization. Participants (both sexes) viewed 2,250 full-color scene images drawn from 30 different scene categories while having their brain activity measured through 256-channel EEG. We examined the variance explained at each electrode and time point of visual event-related potential (vERP) data from nine different whitened encoding models. These ranged from low-level features obtained from filter outputs to high-level conceptual features requiring human annotation. The amount of category information in the vERPs was assessed through multivariate decoding methods. Behavioral similarity measures were obtained in separate crowdsourced experiments. We found that all nine models together contributed 78% of the variance of human scene similarity assessments and was within the noise ceiling of the vERP data. Low-level models explained earlier vERP variability (88 ms post-image onset), while high-level models explained later variance (169 ms). Critically, only high-level models shared vERP variability with behavior. Taken together, these results suggest that scene categorization is primarily a high-level process, but reliant on previously extracted low-level features. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.035436v1?rss=1 Authors: BRUNNER, C., GRILLET, M., SANS-DUBLANC, A., FARROW, K., LAMBERT, T., MACE, E., MONTALDO, G., URBAN, A. Abstract: Imaging of large-scale circuit dynamics is crucial to gain a better understanding of brain function, but most techniques have a limited depth of field. Here we describe vfUSI, a platform for brain-wide volumetric functional ultrasound imaging of hemodynamic activity in awake head-fixed mice. We combined high-frequency 1024-channel 2D-array transducer with advanced multiplexing and high-performance computing for real-time 3D Power Doppler imaging at high spatiotemporal resolution (220x280x175-m3 voxel size, up to 6 Hz). In addition, we developed a standardized software pipeline for registration and segmentation based on the Allen Mouse Common Coordinate Framework, allowing for temporal analysis in 268 individual brain regions. We demonstrate the high sensitivity of vfUSI in multiple experimental situations where stimulus-evoked activity can be recorded using a minimal number of trials. We also mapped neural circuits in vivo across the whole brain during optogenetic activation of specific cell-types. Moreover, we revealed the sequential activation of sensory-motor regions during a grasping water droplet task. vfUSI will become a key neuroimaging technology because it combines ease of use, reliability, and affordability. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.035766v1?rss=1 Authors: Virag, D., Homolak, J., Kodvanj, I., Babic Perhoc, A., Knezovic, A., Osmanovic Barilar, J., Salkovic-Petrisic, M. Abstract: Widely available low-cost electronics encourage the development of open-source tools for neuroscientific research. In recent years, many neuroscientists recognized the open science movement for its potential to stimulate and encourage science that is less focused on money, and more on robustness, validity, questioning and understanding. Here, we wanted to contribute to this global community by creating a research platform based on a common digital kitchen scale. This everyday ordinary kitchen tool is sometimes used in neuroscience research in various ways; however, its use is limited by sampling rate and inability to store and analyze data. To tackle this problem we developed a Platform for Auditory STArtle or PASTA. This robust and simple platform enables users to obtain data from kitchen scale load cells at a high sampling rate, store it and analyze it. Here, we used it to analyze acoustic startle and prepulse inhibition sensorimotor gating in rats treated intracerebroventricularly with streptozotocin, but the system can be easily modified and upgraded for other purposes. In accordance with open science principles, we shared complete hardware design with instructions. Furthermore, we also disclose our software codes written for PASTA data acquisition (C++, Arduino) and acoustic startle experimental protocol (Python) and analysis (R-based Awesome Toolbox for PASTA, ratPASTA R package). To further encourage the development of our PASTA platform we demonstrate its sensitivity by using PASTA-gathered data to extract breathing patterns during rat freezing behavior in our experimental protocol. Copy rights belong to original authors. Visit the link for more info