eneuro
● Society for Neuroscience
All preprints, ranked by how well they match eneuro's content profile, based on 439 papers previously published here. The average preprint has a 0.27% match score for this journal, so anything above that is already an above-average fit. Older preprints may already have been published elsewhere.
Sabatini, B.
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Fluorescent reporters of biological functions are used to monitor biochemical events and signals in cells and tissue. For neurobiology, these have been particularly useful for monitoring signals in the brains of behaving animals. In order to enhance signal-to-noise, fluorescent reporters typically have kinetics that are slower than that of the underlying biological process. This low-pass filtering by the reporter renders the fluorescence transient a leaking integrated version of the biological signal. Here I discuss the effects that low-pass filtering, or more precisely of integrating by convolving with an exponentially decaying kernel, has on the interpretation of the relationship between the reporter fluorescence transient and the events that underlie it. Unfortunately, when the biological events being monitored are impulse-like, such as the firing of an action potential or the release of neurotransmitter, filtering greatly reduces the maximum correlation coefficient that can be found between the events and the fluorescence signal. This can erroneously support the conclusion that the fluorescence transient and the biological signal that it reports are only weakly related. Furthermore, when examining the encoding of behavioral state variables by nervous system, filtering by the reporter kinetics will favor the interpretation that fluorescence transients encode integrals of measured variables as opposed to the variables themselves. For these reasons, it is necessary to take into account the filtering effects of the indicator by deconvolving with the convolution kernel and recovering the underlying biological events before making conclusions about what is encoded in the signals emitted by fluorescent reporters.
Blankenship, L.; Sterrett, S. C.; Martins, D. M.; Findley, T. M.; Abe, E. T. T.; Parker, P. R. L.; Niell, C.; Smear, M. C.
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Neuroscience needs observation. Observation lets us evaluate data quality, judge whether models are biologically realistic, and generate new hypotheses. However, high-dimensional behavioral and neural data are too complex to be easily displayed and eye-tested. Computational methods can reduce the dimensionality of data and reveal statistically robust dynamical structure but often yield results that are difficult to relate back to the underlying biology. In addition, the choice of what parameters to quantify may not capture unexpectedly relevant aspects of the data. To supplement quantification with enhanced qualitative observation, we developed Visualization and Sonification of NeuroData (ViSoND), an open-source approach for displaying multiple data streams using video and sonification. Sonification is nothing new to neuroscience. Scientists have sonified their physiological preparations since Lord Adrians earliest recordings. We extend this tradition by mapping multiple physiological datastreams to musical notes using MIDI. Synchronizing MIDI to video provides an opportunity to watch an animals movement while listening to physiological signals such as action potentials. Here we provide two demonstrations of this approach. First, we used ViSoND to interpret behavioral structure revealed by a computational model trained on the breathing rhythms of freely behaving mice. Second, ViSoND revealed patterns of neural activity in mouse visual cortex corresponding to eye blinks, events that were previously filtered out of analysis. These use cases show that ViSoND can supplement quantitative rigor with observational interpretability. Additionally, ViSoND provides an accessible way to display data which may broaden the audience for communication of neuroscientific findings.
Conlisk, D. E.; Ceau, M.; Fiancette, J.-F.; Winke, N.; Darmagnac, E.; Herry, C.; Deroche-Gamonet, V.
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BackgroundAdvances in in vivo fluorescent imaging have exploded with the recent developments of genetically encoded calcium indicators (GECIs) and fluorescent biosensors. Their use with a bulk imaging technique such as fiber photometry (FP) can be highly beneficial in identifying neuronal signatures in behavioral neuroscience experiments. Popularity of FP has grown rapidly. Initially applied to classical conditioning, its integration into operant behavior paradigms is progressing. However, in operant behavior, protocols can be complex including numerous scheduled events, while behavioral responses can occur in diverse and non-predictable manners. To optimize data processing and analysis, there is a need for a flexible tool to extract and relate behavioral and fiber photometry data occurring over operant sessions. New MethodApplied to cocaine intravenous self-administration (using Imetronic polymodal apparati) and FP recordings in the prelimbic cortex (using Doric Lenses photometry system) in the rat, we established Pyfiber, an outline and open source data analysis python library that facilitates the merge of fiber photometry (using Doric Lenses) with operant behavior (using Imetronic). It allows relating activity changes within a neuronal population to the various behavioral responses and events occurring during operant behavior. ResultsWe show some of the possibilities and benefits of the analytical tool Pyfiber, which helps to: 1. Extract the different types of events that occur in an operant session, 2. Extract and process the fiber photometry signals, 3. Select events of interest and align them to the corresponding fiber photometry signals, 4. Apply the most appropriate type of FP signal normalization and signal analysis according to the studied type of event or behavioral response, 5. Run data extraction and analysis on multiple individuals and sessions at the same time, 6. Collect results in an easily readable format for statistical analysis. From our data and through the use of Pyfiber, we show that we can successfully record and easily analyze calcium transients surrounding events occurring during a cocaine self-administration paradigm in the rat. Comparison with Existing Method(s)While other analytical tools can be used for streamlined fiber photometry analysis, they are either too rigid and specific or too flexible, requiring extensive coding to properly fit the data sets. Additionally, current tools do not permit easy exploration of multiple types of events in parallel- something that is possible with Pyfiber. ConclusionsThis work established an open source resource that facilitates the pairing of fiber photometry recordings (using Doric Lenses photometry system) with operant behavior (using Imetronic polymodal apparati), setting a solid foundation in analyzing the relationship between different dimensions of operant behavior with fluorescent signals from brain regions of interest.
Kolpakova, J.; Marvel-Zuccola, J. D.; Futai, K.; Martin, G.; van der Vinne, V.
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Electrophysiological datasets are typically analyzed under the assumption that repeated measurements of the same unit of analysis (i.e. neuron or animal) can be treated as statistically independent. Recently, this assumption has been questioned and our data confirms and quantifies this skepticism using ex vivo slice recordings of synaptic currents in D1R+ medium spiny neurons in the nucleus accumbens. We therefore present EPHierStats as a statistical framework to analyze electrophysiological datasets with large numbers of measurements (>100) per unit of analysis. This novel analysis framework enables encoding of the full hierarchical relationships between measurements in a mixed-effects general linear model while also analyzing the distribution of values in assessed variables. Our method can easily be adapted to analyze a wide range of repeated-measures electrophysiological experiments. Implementation of the EPHierStats tool will aid the adaption of modern statistical approaches that prevent pseudoreplication and its associated false discovery rate while enabling statistical assessments of the complex relationships inherent to the field of neuroscience.
Kelberman, M. A.; Rodberg, E.; Arabzadeh, E.; Bair-Marshall, C. J.; Berridge, C. W.; Berrocoso, E.; Breton-Provencher, V.; Chandler, D. J.; Che, A.; Davy, O.; Devilbiss, D. M.; Downs, A. M.; Drummond, G.; Dvorkin, R.; Fazlali, Z.; Froemke, R. C.; Glennon, E.; Gold, J. I.; Ito, H.; Jiang, X.; Johansen, J. P.; Kaye, A. P.; Kim, J. R.; Kuo, C.-c.; Liu, R.-j.; Liu, Y.; Llorca-Torralba, M.; McCall, J. G.; McElligott, Z. A.; McKinney, A. M.; Miguelez, C.; Min, M.-Y.; Nowlan, A. C.; Omrani, M.; Pickering, A. E.; Poe, G. R.; Ranjbar-Slamloo, Y.; Razquin, J.; Rodenkirch, C.; Sales, A. C.; Satyasambit,
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The brainstem cell group, locus coeruleus (LC), is present across vertebrates and influences cardiorespiratory, metabolic, immune, and cognitive functions by activating in two putatively distinct firing patterns. Yet, the degree to which the LC firing rates and patterns are homogenous across species has never been assessed due to inherently limited sample sizes. To remedy this, we pooled cross-species data from 20 laboratories to show that firing rates differ across species and are modulated by sex, age, and type of in vitro or in vivo preparation. Contrary to the prevailing dual-mode firing pattern schema, we observed patterns spread across a low-dimensional manifold, with subregions enriched for specific biological factors and neurodegenerative disease models. Our findings show considerable diversity in an ancestral vertebrate neuromodulatory system.
Anesten, F.; Simfors, S.; Ioneskou, K.; Hezso, M.; Gundogdu, B.; Tran, A.; Stjernvall, A.; Ratiglia, V.; Almasri, A.; Loken, L. S.
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Gentle tactile stimulation is associated with positive affect and social bonding, yet the central circuits engaged by such stimuli remain incompletely understood. The lateral parabrachial nucleus (lePB) is a key hub in ascending affective sensory pathways and is robustly activated by aversive stimuli, including pain. Here, we examined neuronal activation in the lePB and the likewise associated subparafascicular nucleus, parvocellular part (SPFp), following different tactile stimulation paradigms in mice. Behavioral analyses confirmed that the soft touch stimuli used in this study were not aversive: mice displayed low aversive facial grimace scores during brushing and von Frey stimulation compared with noxious heat, and showed a preference for a soft tactile environment in a place preference assay. Neuronal activation was assessed using Fos immunohistochemistry following exposure to brushing-based soft touch, a fur-roll paradigm, innocuous punctate touch (von Frey), or noxious heat. Soft touch protocols robustly increased Fos expression in the lePB compared with home cage controls, whereas innocuous punctate touch did not. Notably, the magnitude of activation produced by brushing-based stimuli was comparable to that induced by noxious heat. Using CalcaCre mice, we further found that soft touch recruited a subset of CGRP-expressing neurons in the lePB. In contrast, tactile stimulation produced only modest activation in the SPFp and did not strongly increase overall Fos expression in this region. Together, these findings demonstrate that affective tactile stimulation can engage neuronal populations within ascending parabrachial circuits, including CGRP neurons traditionally associated with nociceptive processing, suggesting that these pathways may encode the salience or affective significance of somatosensory stimuli rather than exclusively aversive input.
Langford, Z. D.; Procyk, E.; Wilson, C. R.
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Beta band rhythms often appear as brief bursts, but how variations in burst properties impact neural function is unclear. We probed beta burst heterogeneity by developing two complementary detection algorithms. One isolates brief high amplitude events (bursts of power, BoP) and another that identifies consistent oscillations that span multiple cycles (bursts of consistency, BoC). Examining frontal LFP and ECoG recordings from mice and macaques, these two burst types occupied the same 15 to 30 Hz frequency band yet showed minimal temporal overlap, indicating independent phenomena probably with distinct neural generators. Crucially, when task demands shifted between high and low cognitive control states, BoC bursts were enriched during demanding phases, whereas BoP bursts dominated routine phases. These results demonstrate that frontal beta activity comprises at least two rhythmically distinct regimes linked to different levels of cognitive control. Our dual mode framework refines mechanistic models of transient oscillations and underscores the significance of burst waveform diversity for flexible brain function.
Nigro, M. J.; Kirikae, H.; Kjelsberg, K.; Raveendran, R. N.; Witter, M.
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The wide diversity of cortical inhibitory neuron types populating the cortex allows the assembly of diverse microcircuits and endows these circuits with different computational properties. Thus, characterizing neuronal diversity is fundamental to describe the building blocks of cortical microcircuits and probe their function. To this purpose, the mouse has emerged as a powerful tool to genetically label and manipulate specific inhibitory cell-types in the mammalian brain. Among these cell-types, the parvalbumin-expressing interneuron type (PV-INs) is perhaps the most characterized. Several mouse lines have been generated to target PV-INs. Among these mouse lines, the PV-IRES-Cre lines is the most widely used and demonstrated a high specificity and efficiency in targeting PV-INs in different cortical areas. However, a characterization of the performance across cortical regions is still missing. Here we show that the PV-IRES-Cre mouse line labels only a fraction of parvalbumin immunoreactive neurons in perirhinal cortex and other association areas. Our results point to a yet uncharacterized diversity within the PV-INs and emphasize the need to characterize these tools in specific cortical areas.
Benites, N. M.; Rodrigues, B.; da Siveira, C. H.; Leao, R. M.
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The dorsal cochlear nucleus (DCN) in the auditory brainstem integrates auditory and somatosensory information. Mature fusiform neurons express two qualitative intrinsic states in equal proportions: quiet, with no spontaneous regular action potential firing, or active, with regular spontaneous action potential firing. However, how these firing states and other electrophysiological properties of fusiform neurons develop during early postnatal days to adulthood is not known. Thus, we recorded fusiform neurons from mice from P4 to P21 and analyzed their electrophysiological properties. In the pre-hearing phase (P4-P13), we found that fusiform neurons are mostly quiet, with the active state emerging after hearing onset at P14. Subthreshold properties present more variations before hearing onset, while action potential properties vary more after P14, developing bigger, shorter, and faster action potentials. Interestingly, the activity threshold is more depolarized in pre-hearing cells suggesting that persistent sodium current (INaP) increases its expression after hearing. In fact, INaP increases its expression after hearing, accordingly with the development of active neurons. Thus, we suggest that the post-hearing expression of INaP creates the active state of the fusiform neuron. At the same time, other changes refine the passive membrane properties and increase the speed of action potential firing of fusiform neurons.
Corrigan, B. W.; Errington, S. P.; Sajad, A.; Schall, J. D.
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Conflict--the magnitude of co-activation of mutually incompatible response processes--was proposed to explain how cognitive control is invoked (Botvinick et al. 2001) and continues to engage debate (Becker et al. 2024). Original observations consistent with this construct emphasized the primary contribution of cingulate cortex (CC) based on human functional imaging (Botvinick et al., 1999; Carter et al., 2000) and electroencephalogram (Yeung, Botvinick, & Cohen, 2004). In countermanding tasks conflict arises through co-activation of competing GO and STOP processes (Boucher et al. 2007; Schall & Boucher 2007; Sajad et al. 2022). Single neuron activity representing conflict has been described in the supplementary motor cortex of human epilepsy patients (Fu et al., 2019; Sheth et al., 2012) and of macaque monkeys (Sajad, Errington, & Schall, 2022; Stuphorn, Taylor, & Schall, 2000) and in human cingulate cortex (Fu et al., 2019; Sheth et al., 2012) but not in monkey cingulate cortex (Ebitz & Platt, 2015; Ito, Stuphorn, Brown, & Schall, 2003; Nakamura, Roesch, & Olson, 2005). This lack of homology generated debate about the utility of macaques for investigation of cognitive control (Cole et al. 2009; Schall & Emeric 2010). With higher-resolution, less-biased samples, we re-examined the presence of a conflict signal in cingulate cortex of monkeys. Neurons modulating specifically when response conflict was maximal were found in cingulate cortex-- more commonly in the dorsal than the ventral bank. However, such neurons were much more common in supplementary motor cortex. These data confirm the presence of a conflict signal in medial frontal cortex and demonstrate that it can be found in a small fraction of neurons in cingulate cortex. Further research is needed to determine if the weak response conflict signal in cingulate cortex is sufficient or negligible.
Sharma, S.; Srivastav, H. K.; Bandyopadhyay, S.
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So far, our understanding on the role of the auditory cortex (ACX) in processing visual information has been limited to infragranular layers of the ACX, which have been shown to respond to visual stimulation. Here, we investigate the neurons in supragranular layers of the mouse ACX using 2-photon calcium imaging. Contrary to previous reports, here we show that more than 20% of responding neurons in layer2/3 of the ACX respond to full-field visual stimulation. These responses occur by both excitation and hyperpolarization. The primary ACX (A1) has a greater proportion of visual responses by hyperpolarization compared to excitation likely driven by inhibitory neurons of the infragranular layers of the ACX rather than local layer 2/3 inhibitory neurons. Further, we found that more than 60% of neurons in the layer 2/3 of A1 are multisensory in nature. We also show the presence of multisensory neurons in close proximity to exclusive auditory neurons and that there is a reduction in the noise correlations of the recorded neurons during multisensory presentation. This is evidence in favour of deep and intricate visual influence over auditory processing. The results have strong implications for decoding visual influences over the early auditory cortical regions. Significance statementTo understand, what features of our visual world are processed in the auditory cortex (ACX), understanding response properties of auditory cortical neurons to visual stimuli is important. Here, we show the presence of visual and multisensory responses in the supragranular layers of the ACX. Hyperpolarization to visual stimulation is more commonly observed in the primary ACX. Multisensory stimulation results in suppression of responses compared to unisensory stimulation and an overall decrease in noise correlation in the primary ACX. The close-knit architecture of these neurons with auditory specific neurons suggests the influence of non-auditory stimuli on the auditory processing.
Seo, S.; Bharmauria, V.; Schuetz, A.; Yan, X.; Wang, H.; Crawford, J. D.
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Single-unit (SU) activity - action potentials isolated from one neuron -- has traditionally been employed to relate neuronal activity to behavior. However, recent investigations have shown that multi-unit (MU) activity - ensemble neural activity recorded within the vicinity of one microelectrode - may also contain accurate estimations of task-related neural population dynamics. Here, using a well-established model-fitting approach, we compared the spatial codes of SU response fields with corresponding MU response fields recorded from the frontal eye fields (FEF) in head-unrestrained monkeys (Macaca mulatta) during a memory-guided saccade task. We focused on characterizing the visuomotor transformation from Target-in-Eye coordinates to future Gaze-in-Eye coordinates (Sajad et al., 2015). Most SU visual response fields coded targets (with some predicting Gaze), whereas the MU population only coded targets. Most SU motor responses coded Gaze, but many still retained a target code. In contrast, MU motor activity predominantly coded Gaze with very little target coding. Finally, both SU and MU populations showed a progressive transition through intermediate Target-to-Gaze codes during the delay period, but the MU activity showed a smoother transition. These results confirm the theoretical and practical potential of MU activity recordings as a biomarker for fundamental sensorimotor transformations (e.g., Target-to-Gaze coding in the oculomotor system), while also highlighting the importance of SU activity for coding more cognitive (e.g., predictive / memory) aspects of sensorimotor behavior. SIGNIFICANCE STATEMENTMulti-unit recordings (undifferentiated signals from several neurons) are relatively easy to record and provide a simplified estimate of neural dynamics, but it is not clear which single-unit signals are retained, amplified, or lost. Here, we compared single-/multi-unit activity from a well-defined structure (the frontal eye fields) and behavior (memory-delay saccade task), tracking their spatial codes through time. The progressive transformation from target to gaze coding observed in single-unit activity was retained in multi-unit activity, but gaze prediction (in the visual response) and target memory (in the motor response) were lost. This suggests that multi-unit activity provides an excellent biomarker for healthy sensorimotor transformations, at the cost of missing more subtle cognitive signals.
Albarran, E.; Fushiki, A.; Nelson, A.; Ng, D.; Chaimowitz, C.; Nikoobakht, L.; Sippy, T.; Peterka, D. S.; Costa, R. M.
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The basal ganglia and midbrain dopaminergic systems are critical for motor control, reward processing, and reinforcement learning, with dysfunction in these systems implicated in numerous neurodegenerative and neuropsychiatric disorders. To enable precise genetic targeting of key neuronal populations, we generated and characterized five knock-in mouse lines: Drd1-Cre, Adora2a-Cre, Drd1-FlpO, Adora2a-FlpO, and DAT-FlpO. These lines allow for Cre-or FlpO-mediated recombination in dopamine D1 receptor-expressing spiny projection neurons (SPNs), adenosine A2a receptor-expressing SPNs, and dopamine transporter (DAT)-expressing neurons in the midbrain. Histological analyses confirmed recombinase activity in expected brain regions, and whole-cell electrophysiological recordings validated the intrinsic excitability profiles of each neuronal subpopulation. These tools provide high specificity and reliability for studying basal ganglia circuitry and dopaminergic neurons. By enabling targeted manipulations, these openly available knock-in lines will advance research into the neural mechanisms underlying motor control, reward, and neuropsychiatric diseases.
Dutkiewicz, A. P.; Morielli, A. D.
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The endogenous opioid system of the cerebral cortex is an important feature of antinociception and reward valuation through its modulation of inhibitory neocortical interneurons. Dysregulation of this system, through disease or drugs, disrupts the reward system and contributes to eating and mood disorders, impulsive actions, and addiction. Impulsive behaviors can be induced experimentally through infusion of the opioid receptor specific agonist [D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin (DAMGO) into the frontal cortex in animal models. The mechanism involves increased potassium channel function, which suppresses neocortical interneuron activity. However, much of the data on the effect of this receptor on ion channels have been derived from noncortical ORs, and the identity and effects of the ion channels that the OR targets in neocortical neurons have not been thoroughly investigated. Based on previous experiments by other labs, we hypothesized that the OR could activate -dendrotoxin (DTX) sensitive channels (Kv1.1, Kv1.2, and Kv1.6 subunits) to exert its inhibitory effects in cortical interneurons. This, in turn, is expected to confer a variety of effects on passive and active electrical properties of the cell. We performed patch-clamp electrophysiology to examine the electrophysiological effects of ORs in cultured neocortical interneurons. We found that a range of features among the 54 membrane and action potential properties we analyzed were modulated by ORs, including action potential kinetics and frequency. The Kv1.1, Kv1.2, and Kv1.6 inhibitor DTX reversed some effects on action potential frequency, but not effects on their kinetics. Therefore, ORs in neocortical interneurons influence DTX-sensitive channels, as well as other channels, to modulate action potential kinetics and firing properties.
Mathews, M. A.; Tung, V. W. K.; Reader-Harris, E.; Murray, A. J.
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The vestibular system is a critical sensory modality required for coordinated movement, balance and our ability to interact with the surrounding environment. Vestibular sensory neurons provide the nervous system with information about head rotation and acceleration. However, the nervous system can also modify the activity of sensory neurons and hair cells via the actions of the efferent vestibular system (EVS). The function of the EVS has remained unknown partly because of an inability to target efferent vestibular neurons in a selective manner to understand their synaptic inputs and function during behaviour. Here, we present a novel method for the selective targeting and expression of flp-recombinase in EVS neurons. We take advantage of the dual expression of choline acetyl transferase (ChAT) and calcitonin gene related peptide (CGRP) in these neurons to develop an adeno-associate virus (AAV) that expresses a gene only in neurons with this intersectional expression. We use this system to map the monosynaptic inputs to EVS neurons and show inputs from distinct populations of brainstem and midbrain regions indicating a functional role as a multimodal processing center and integrator for the vestibular periphery. To demonstrate the applicability of our technology in behavioural assays, we performed a preliminary behaviour analysis in mice with disrupted EVS function. While more bespoke assays are required to ascertain EVS function/s, our viral method presents a novel tool for investigators examining the role of the vestibular system and its central circuits.
King, C. D.; Groh, J. M.
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Eye movement-related eardrum oscillations (EMREOs) appear to consist of a pulse of oscillation occurring in conjunction with saccades. However, this apparent pulse could occur either because there is an increase in energy at that frequency at the time of saccades (a true pulse), or because there is saccade-related phase resetting of ongoing energy at that frequency band, thus appearing like a pulse when averaged in the time domain across many trials. Here we conducted a spectral analysis at the individual trial level in humans performing a visually guided saccade task to determine whether the power at the EMREO frequency (30-45 Hz) is higher during saccades than during steady fixation. We found both an increase in sound power in the EMREO frequency band associated with saccades, i.e. sound pulses at the individual trial level, as well as, phase resetting at saccade onset/offset. While both factors contribute to the apparently pulse-like EMREO signal, phase resetting appears to be more prevalent across participants. The prevalence of phase resetting has implications for the underlying mechanism(s) producing EMREOs as well as functional consequences for how the ear might respond to incoming sound in an eye-position dependent fashion.
O'Connell, S.; Michaels, J. A.; Wang, R.; Mamidipaka, S.; Venkatesh, M.; Aresh, N.; Pachitariu, M.; Pruszynski, J. A.; Sober, S. J.; Pandarinath, C.
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Understanding how neural signals control muscle activity during behavior is a key challenge in motor neuroscience. To this end, recent advances in intramuscular multielectrode arrays have enabled high-quality multichannel recordings of many motor unit action potentials (MUAPs) in freely moving subjects. However, identifying individual MUAP events within multichannel recordings is a significant challenge for existing spike sorting methods, which are typically optimized for identifying action potentials from neurons in the brain. To overcome this challenge, we developed the Enhanced Motor Unit sorter (EMUsort), an extension of Kilosort4 (KS4) that achieves high-performance MUAP spike sorting. We applied EMUsort to high-resolution intramuscular recordings from rat forelimb during locomotion and monkey forelimb during a reaching task. EMUsort improves upon prior methods by addressing key challenges encountered with MUAP datasets, including: 1) long time delays across electrodes due to propagation along muscle fibers, 2) more complex waveform shapes compared to neuronal action potentials, and 3) a high degree of MUAP overlap due to cumulative motor unit recruitment. We compared EMUsort to existing spike sorting methods quantitatively using simulated datasets that closely emulated the rat and monkey datasets we recorded. EMUsort provided median error rate reductions of 67.5% and 49.9% during periods of high motor unit activation for the rat and monkey datasets, respectively. In sum, EMUsort provides a substantial improvement to MUAP spike sorter accuracy, especially during regions of high MUAP overlap, in an easy-to-use software package.
Travers, S.; Kalyanasundar, B.; Klimovich, C.
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The rostral nucleus of the solitary tract (rNST) is the initial central site for taste processing. This nucleus has a complex circuitry and multiple cell types with different response properties, connectivity, and morphology (Travers and Travers 2018). However, unlike its visceral counterpart, the caudal NST, neurochemical phenotypes in rNST are poorly defined. Recent studies have begun to probe this gap. Based on fiber photometry, optogenetics, and cell-type specific deletion. For example, one group proposed that somatostatin (SST) rNST neurons, neither calbindin or dynorphin cells, responded specifically to bitter stimuli and that these neurons were necessary for suppression of quinine-induced licking (Jin, Fishman et al. 2021) (Zhang, Jin et al. 2019). The present study employed in situ hybridization, optotagging, and chemogenetic suppression in male and female mice to demonstrate that SST neuron function is more complex. Although most SST neurons responded optimally to bitter stimuli, many others were activated by different qualities and some non-SST neurons responded to bitter tastants. Moreover, roughly equal proportions of SST neurons expressed excitatory (VGLUT2) or inhibitory (VGAT) markers. Suppressing SST neural activity with DREADDS enhanced licking to both quinine and sucrose suggesting that neural activity elicited by the aversive bitter stimulus was suppressed whereas licking elicited by the sweet, preferred stimulus was increased. We hypothesize that these effects arise from suppressing excitatory quinine-responsive SST neurons but that a separate population of inhibitory SST neurons synapse on sucrose-responsive cells. Significance StatementRecent studies have revealed molecular heterogeneity of gustatory system neurons. However, it is unclear whether molecularly-distinct cells are associated with specific roles. The current study investigated somatostatin (SST) neurons in rNST, the first central hub for taste processing. Well over half were inhibitory, expressing VGAT, but a substantial proportion were excitatory, expressing VGLUT2. A narrow majority responded optimally to the bitter quality and none to NaCl, but other SST cells responded most vigorously to sweet, umami, or sour stimuli. Subsets of neurons not expressing SST responded best to each quality, including bitter. Suppressing activity in SST neurons dampened behavioral avoidance to quinine but enhanced consummatory responses to sucrose. Thus, SST rNST neurons exhibited varied functional characteristics but also clear distinctiveness.
Millett, M.; Heuberger, A.; Martin Castosa, E.; Comite, A.; Wagner, P.; Hall, D.; Gallardo, I.; Chambers, N. E.; Wagner, L.; Moehle, M. S.
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The heterotrimeric G-protein subunit, Golf, acts to transduce extracellular signals through G-protein coupled receptors (GPCRs) and stimulates adenylyl cyclase mediated production of the second messenger cyclic adenosine monophosphate. Numerous mutations in the GNAL gene, which encodes Golf, have been identified as causative for an adult-onset dystonia. These mutations disrupt GPCR signaling cascades in in vitro assays through several mechanisms, and this disrupted signaling is hypothesized to lead to dystonic motor symptoms in patients. However, the cells and circuits that mutations in GNAL corrupt are not well understood. Published patterns of Golf expression outside the context of the striatum are sparse, conflicting, often lack cell type specificity, and may be confounded by expression of the close GNAL homolog of GNAS. Here, we use RNAScope in-situ hybridization to quantitatively characterize Gnal mRNA expression in brain tissue from wildtype C57BL/6J adult mice. We observed widespread expression of Gnal puncta throughout the brain, suggesting Golf is expressed in more brain structures and neuron types than previously accounted for. We quantify transcripts at a single cell level, and use neuron type specific markers to further classify and understand patterns of GNAL expression. Our data suggests that brain regions classically associated with motor control, initiation, and regulation show the highest expression of GNAL, with Purkinje Cells of the cerebellum showing the highest expression of any neuron type examined. Subsequent conditional Gnal knockout in Purkinje cells led to markedly decreased intracellular cAMP levels and downstream cAMP-dependent enzyme activation. Our work provides a detailed characterization of Gnal expression throughout the brain and the biochemical consequences of loss of Golf signaling in vivo in neurons that highly express Gnal.
Birman, D.; Chapuis, G.; Faulkner, M.; Rossant, C.; the International Brain Laboratory, ; Benson, J.; Catarino, J. A.; Churchland, A. K.; Hu, F.; Huntenburg, J. M.; Khanal, A.; Krasniak, C.; Lau, P. Y. P.; Meijer, G. T.; Miska, N. J.; Noel, J.-P.; Pan-Vazquez, A.; Roth, N.; Schartner, M.; Socha, K. Z.; Steinmetz, N. A.; Urai, A. E.; Wells, M. J.; West, S. J.; Winter, O.
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Methodological advances in neuroscience have enabled the collection of massive datasets which demand innovative approaches for scientific communication. Existing platforms for data storage lack intuitive tools for data exploration, limiting our ability to interact effectively with these brain-wide datasets. We introduce two public websites: (Data and Atlas) developed for the International Brain Laboratory which provide access to millions of behavioral trials and hundreds of thousands of individual neurons. These interfaces allow users to discover both the raw and processed brain-wide data released by the IBL at the scale of the whole brain, individual sessions, trials, and neurons. By hosting these data interfaces as websites they are available cross-platform with no installation. By releasing each sites code as a modular open-source framework, other researchers can easily develop their own web interfaces and explore their own data. As neuroscience datasets continue to expand, customizable web interfaces offer a glimpse into a future of streamlined data exploration and act as blueprints for future tools.