BACKGROUND:Glioma is a common primary malignant tumor; accurate intraoperative localization, especially of invasion depth, is critical for resection and postoperative treatment. Preoperative MRI and neuronavigation is reliable mainly before craniotomy, but brain shift begins to compromise image-to-patient registration as soon as the skull and dura are opened, before cortical resection even starts, and static MRI alone lacks functional information. Since glioma infiltration affects neural electrical activity, this study explored ECoG-based measurement of invasion depth. NEW METHOD:ECoG electrodes were categorized into three types (Glioma Invading Subcortex [GIS], Glioma Invading Cortex [GIC], Normal-appearing cortex within patients with glioma [NC]) by underlying tumor invasion. Spectral power features across frequency bands were extracted, and linear/nonlinear methods evaluated their correlation with invasion depth. RESULTS:GIS and GIC had significantly lower spectral power than NC. GIC showed a strong negative correlation between invasion depth and spectral power, strongest in the beta band (r = -0.642). Linear and nonlinear models had similar fitting errors, with the linear model more stable across patients. COMPARISON WITH EXISTING METHODS:Unlike preoperative MRI (constrained by brain shift and inadequate functional data), this method uses real-time ECoG signals for dynamic intraoperative measurement with functional insights. CONCLUSIONS:This study suggests that tumor infiltration is associated with suppression of cortical electrical activity and provides preliminary evidence of a relationship between ECoG signals and glioma invasion depth. These findings indicate a potential exploratory framework for assessing tumor infiltration intraoperatively, which may complement preoperative imaging; however, further validation in larger cohorts is required before clinical application can be established.
BACKGROUND:Recovery after peripheral nerve injury (PNI), even with surgical intervention, is often poor. The current standard in surgical repair of PNIs, microsuture of the severed epineurium is technically demanding, time-consuming, and routinely results in fascicular misalignment. NEW METHOD:Nerve Tape is a coaptation device that circumvents the need for microsuture. Nerve Tape repairs improve fascicular alignment, nerve conduction velocities, as well as muscle and axon morphologies compared to microsuture repairs. However, the efficacy of Nerve Tape for small diameter nerve repairs is understudied, and no reports exist directly comparing sexes. We compared sensory and locomotor recovery as well as the pattern of motor reinnervation after sciatic nerve transection and repair with either microsuture or Nerve Tape in rats of both sexes. Young adult male and female Lewis rats received a sciatic nerve transection repaired with either microsuture or Nerve Tape. Locomotor and sensory testing was performed weekly post-injury. At either 8- or 12-weeks post-repair, motoneurons whose axons had regenerated into the anterior tibialis muscle were retrogradely labeled, allowing for assessment of motoneuron number and spinal location. RESULTS AND COMPARISON WITH EXISTING METHODS:Nerve Tape repairs took significantly less time than microsuture. Behavioral recovery outcomes were comparable after microsuture and Nerve Tape repairs and did not differ between sexes. Retrograde labeling of motoneurons demonstrated that motor axons successfully regenerated to appropriate and inappropriate muscles regardless of repair type or sex. CONCLUSION:Our data supports the efficacy of Nerve Tape to repair small diameter nerve injuries in both males and females.
BACKGROUND:Visual neuroscience research has adopted the mouse as one of its primary animal models. Collection of perceptually driven behavior in these mice often involves head fixation to present the visual stimulus under controlled conditions and water restriction to motivate responses. However, both head fixation and water restriction can induce physiological stress. NEW METHOD:Here, we adapted a popular open-source two-alternative-forced-choice (2AFC) visual psychophysics apparatus to allow unrestrained mice to maintain consistent stimulus viewing position while performing trials for hedonic reward. The stereotyped head positioning further enabled wireless power transfer to implanted LEDs, permitting transcranial optogenetic manipulation of targeted interneuron subtypes in visual cortex during behavior. RESULTS:Unrestrained mice learned a 2AFC contrast detection task, and required an average of 22.4 days to reach criterion accuracy. Mice showed strong task engagement with hedonic reward, and produced high quality psychometric functions based on thousands of trials. COMPARISON WITH EXISTING METHODS:Task acquisition times and accuracy were comparable to published head-fixed paradigms. Cortical illumination modulated contrast detection in a manner consistent with previous findings. CONCLUSIONS:This approach provides a less stressful and experimentally accessible alternative to head-fixation, lowering technical barriers while preserving the precision required for visual psychophysics.
BACKGROUND:Multisensory room-based interventions have shown positive effects in various neurological disorders, although most evidence is based on subjective assessments. Further research based on quantitative and objective metrics is needed. NEW METHOD:An EEG-based spectral analysis was applied to objectively assess the effects of a general-purpose multisensory room intervention. Resting-state EEG recordings were obtained before and after the intervention in 54 participants: healthy controls (C), individuals with cerebral palsy (CP), and individuals with traumatic brain injury (TBI). Relative power in standard frequency bands and several power ratios were computed across four brain regions of interest. Non-parametric statistical analyses with false discovery rate correction were performed. RESULTS:Significant Pre-Post differences (Wilcoxon signed-rank test, p < 0.05) were found for the C and CP groups across different brain regions, particularly in the alpha band and the alpha/beta ratio. The TBI group did not exhibit significant differences, although qualitative trends suggested similar modulation. Intergroup comparisons did not reveal significant differences (Mann-Whitney U test, p < 0.05). COMPARISON WITH EXISTING METHODS:Unlike most previous studies relying on subjective measures, this work provides objective evidence based on EEG spectral biomarkers and extends prior EEG approaches by jointly analyzing multiple bands and ratios. CONCLUSIONS:A multisensory room-based intervention may have promoted relaxation and stress reduction in C and CP groups, while no significant but qualitative changes were observed in the TBI group. No significant intergroup differences were found, but similar trends with different magnitudes suggest comparable therapeutic benefits across groups, highlighting the need for tailored interventions.
BACKGROUND:The novel object recognition (NOR) test is widely used to assess object recognition memory in rodents, but manual scoring is labour-intensive and susceptible to interobserver variability. NEW METHOD:We developed an open-source tool combining DeepLabCut (DLC) with explicit numerical criteria. DLC estimated nose, head, and object coordinates in Sprague-Dawley rats. A Python algorithm classified exploration using grid-searchoptimised distance, angle, and likelihood thresholds. Low-likelihood frames, including those involving object occlusion during climbing, were excluded. RESULTS:On an independent dataset of 18,000 frames, sensitivity and positive predictive value were 97% and 83% for the novel object and 97% and 88% for the familiar object, respectively. Across 24 NOR sessions, automated measurements showed high agreement with the mean scores of two independent blinded observers for novel object exploration time (r = 0.87; ICC(2,1) = 0.86), familiar object exploration time (r = 0.96; ICC(2,1) = 0.95), and the novelty discrimination index (NDI) (r = 0.95; ICC(2,1) = 0.95). Bland-Altman analysis showed no evidence of fixed or proportional bias; the 95% limits of agreement for NDI were -0.09 to 0.09. COMPARISON WITH EXISTING METHODS:The method uses explicitly reported numerical thresholds that can be independently verified and recalibrated. Agreement and systematic bias were evaluated without requiring proprietary analysis software. CONCLUSIONS:The DLC-based method showed strong agreement with manual scoring under the conditions tested and provides a transparent, accessible approach to automated NOR analysis.
Background Understanding natural fear responses in rodents provides valuable insights into the mechanisms underlying stress and anxiety. New Method In this study, we developed a novel behavioral paradigm to assess fear responses in Long-Evans rats using a combination of natural and artificial predator cues: coyote urine and a remote-controlled (RC) artificial snake. These cues were integrated into a two-choice compartment arena to evaluate ethologically relevant defensive behaviors, including avoidance, freezing, head-out risk assessment, and escape. Results The coyote odor alone produced only a mild fear response (freezing during 5% of the first exposure session), while the RC snake elicited freezing during 33% of the session. Combining the two cues elicited a more robust fear response (39% freezing) and potentiated the behavioral significance of the coyote urine so that it robustly served as a reminder cue for fear memory during subsequent testing over 3 days (freezing 19%, 21% and 32%). The combination of odor and RC snake also produced reliable avoidance during the first exposure (92% of time in safe compartment). The avoidance remained high during subsequent days only if the odor cue was present (81%-90% avoidance). Comparison with existing methods The two-chamber design offers robust, measurable behavior compared to similar tasks that use an open field with predator cues. Avoidance and freezing have traditionally been induced by painful stimuli. Conclusions The suggested paradigm can be useful for investigating mechanisms underlying fear and anxiety and predator-prey interactions. It balances ecological validity with experimental control, advancing the study of fear-based behaviors.
BACKGROUND:Temporal domain choices and motion correction strategies are critical for rs-fMRI analysis. NEW METHOD:This study compared the combined effect of temporal domain and motion correction choices of two widely-used and methodologically distinct preprocessing strategies implemented within FSL and CONN pipelines on test-retest reliability of the language and sensorimotor networks. METHODOLOGY:27 healthy volunteers underwent two rs-fMRI sessions. Data were analyzed using seed-based analysis for seven regions of interest within the language and sensorimotor networks. All preprocessing parameters were unified between FSL and CONN, except for their default temporal domain preprocessing and motion correction strategies to enable direct comparison. Test-retest reliability was primarily assessed using Intraclass Correlation Coefficient (ICC 3,1), with secondary analyses of group-level intersession FC variations. RESULTS:The FSL pipeline yielded significantly higher voxel-level reliability (p = 0.031), particularly for the sensorimotor network. At the ROI level, FC map reliability was comparable between pipelines. Group-level analyses revealed that FSL captured changes in basal ganglia connectivity patterns not detected by CONN. Furthermore, inter-network FC stability varied markedly between both pipelines. COMPARISON WITH OTHER METHODS:This method evaluates the impact of complete end to end rs-fMRI preprocessing strategies as implemented in clinical practice instead of segregating their impact in previous research work. CONCLUSION:Preprocessing strategy has a network-dependent impact on the test-retest reliability of the rs-fMRI functional connectivity of the language and sensorimotor networks. The language network benefits from CONN's aggressive artifact removal. Conversely, the sensorimotor network, specifically subcortical components, requires the preservation of higher-frequency signals, favoring FSL approach.
BACKGROUND:Primary cortical cultures from neonatal rat brain are widely used in in vitro models of neuronal network development and disease, but depend on freshly isolated tissue, which limits experimental flexibility and increases animal use. Cryopreservation may offer a solution, but primary cortical cells from P1 rat pups have proven difficult to freeze successfully with standard protocols. NEW METHOD:We evaluated CryoStor CS10 for cryopreservation of P1 rat cortical cells. Following storage in liquid nitrogen for up to two years, thawed cells were compared with freshly isolated cells for viability, cellular composition, and electrophysiological network function in multi-electrode array cultures, including inhibitory responses to picrotoxin. RESULTS:Although post-thaw recovery was lower than for freshly prepared material, cryopreserved cells generated cultures with similar astrocyte-to-neuron ratios, similar fractions of inhibitory neurons, and largely comparable electrophysiological network properties. Within our workflow and regulatory context, our method reduced the number of animals required per experiment by approximately 90%. COMPARISON WITH EXISTING METHOD(S):CryoStor CS10 has previously been validated for cryopreservation of embryonic cortical neurons of mice and sensitive stem-cell populations. We show that CryoStor CS10 also preserves the capacity of mixed postnatal rat cortical cultures to form functional neuron-astrocyte networks with maintained spontaneous and inhibitory network activity. CONCLUSION:We present a practical cryopreservation method for primary rat cortical cells that increases experimental flexibility and can substantially reduce the number of animals required for in vitro brain-on-chip research.
BACKGROUND:Understanding cognition is essential for advancing treatments for human disorders. Rodent studies remain important for investigating underlying mechanisms. Traditional testing often involves handling, isolation and experimenter variability, which can reduce data quality. NEW METHOD:We present the automated Social RatPad, a home-cage access-control system enabling socially housed rats to reach touchscreen-based RatPad chambers without manual separation. The chamber presents stimuli, records responses and delivers pellets; this study validates the access-control and logging layer connecting it to a social home cage. The system combines monitored corridors, a modified One-rat turnstile, RFID identification and automated secondary gates. During passage, an Arduino receives the gate state and RFID result, samples a load cell and controls the secondary gate, while a separate program manages RFID assignments, communication, monitoring and logging. The load-cell station provides an auxiliary health-related signal. Hardware, reconstruction files, control software and validation scripts are provided as Supplementary Material. RESULTS:Of 58 human-confirmed corridor traversals, 57 had valid RFID read support (98.28%), and traversal-duration agreement was quantified across matched events. Deployment demonstrated ready corridor use and consistent generation of structured behavioral data. COMPARISON WITH EXISTING METHODS:Compared with existing rat touchscreen and home-cage approaches, the system addresses controlled access in pair-housed rats while preserving individual attribution and reducing manual intervention. CONCLUSIONS:The automated Social RatPad supports continuous, low-intervention cognitive testing and provides a foundation for scalable behavioral neuroscience applications.
BACKGROUND:Primary microglia are essential for studying neuroinflammation and microglia-mediated neuropathology. However, conventional shaking-based isolation methods often yield unstable purity, astrocytic contamination, and heterogeneous activation states. NEW METHOD:We developed a multidimensional optimization strategy for primary rat microglia isolation by systematically integrating three key parameters: neonatal developmental stage, culture vessel geometry, and Percoll density gradient purification. Microglial purity, identity, viability, and functional responsiveness were evaluated by flow cytometry, immunofluorescence, Western blotting, qPCR, and ELISA. RESULTS:Compared with postnatal day 7 (P7), postnatal day 3 (P3) tissue provided higher isolation efficiency, greater culture homogeneity, and reduced astrocytic contamination. Culture in 6-cm dishes improved cell adhesion and morphological consistency. Percoll density gradient purification further increased microglial purity by approximately 20-30% while maintaining acceptable cell recovery. The optimized protocol consistently yielded cultures with stable purity (80-90%), high IBA1 positivity (>90%), increased metabolic activity, and lower basal activation. Following lipopolysaccharide stimulation, purified microglia exhibited robust inflammatory responses, including increased cytokine secretion and inflammatory gene expression. COMPARISON WITH EXISTING METHODS:Compared with conventional shaking-based isolation, the optimized workflow improves purity, reduces contamination, enhances reproducibility, and preserves functional responsiveness without requiring specialized equipment. CONCLUSIONS:This study provides a practical and reproducible strategy for improving microglial purity and experimental consistency and offers a reliable experimental platform for neuroinflammation research and mechanistic studies.
BACKGROUND:Motor imagery (MI) brain-computer interfaces (BCI) rely on precise electroencephalogram (EEG) classification. However, issues such as the reliance on extensive manual experience for MI-EEG model design, parameter tuning, and optimization directions, along with the poor task flexibility of foundation models and state degradation during long-term multi-agent iterations, severely restrict the state-of-the-art (SOTA) efficiency of MI-EEG. NEW METHOD:To address these challenges, we propose AutoMI, a novel framework that uses multi-agent automated rapid iterations to construct SOTA MI-EEG models. AutoMI introduces a hybrid decision mechanism that tightly couples Q-learning strategies with deterministic rules. By integrating planning, execution, and output agents with predefined tools, AutoMI ensures broad general applicability across various hyperparameter optimizations and structural improvements. Furthermore, AutoMI integrates experience tracking and rollback mechanisms to prevent ambiguous optimization. RESULTS:In evaluations on the IV2a, OpenBMI, and ECUST-MI datasets, the SOTA models finally constructed through AutoMI iterations achieve accuracies of 77.62%, 78.08%, and 83.02%, with maximum improvement reaching 24.69%, 23.35%, and 23.28% respectively. Furthermore, the average time per iteration for a single subject on the OpenBMI dataset is approximately 500 s. COMPARISON WITH EXISTING METHODS:Compared with automated optimization algorithms, the accuracies increase by 18.42%, 9.27%, and 19.25% respectively, demonstrating the effectiveness of the proposed AutoMI framework and proving that its optimization capability reaches SOTA. CONCLUSION:Experimental results indicate that AutoMI provides a novel perspective and framework design reference for future BCI model optimization.
BACKGROUND:Cerebral microembolism contributes to silent brain infarction and procedure-related ischemic brain injury during catheter-based endovascular interventions. However, reproducible experimental platforms simulating particulate embolization under endovascular conditions remain limited. NEW METHOD:We developed a rat model of microembolic brain injury using percutaneous coaxial microcatheter delivery of zirconia beads under fluoroscopic guidance. Zirconia beads (15 µm) were loaded as a sedimented column in iodinated contrast medium within an inner microcatheter, advanced coaxially through an outer microcatheter, and delivered selectively to the left internal carotid artery (ICA) territory via the caudal ventral artery. Animals with an ICA curvature angle > 40° were excluded to reduce procedure-related variability. RESULTS:Among 25 male Sprague-Dawley rats, three were excluded before embolization because of unfavorable anatomy, leaving 18 embolized rats and four sham-operated controls for analysis. The median operative time was 8.5 min (IQR, 6.3-11.0). No procedure-related mortality or significant vasospasm occurred. TTC staining at 24 h demonstrated ipsilateral infarcts in all embolized animals, with a median infarct volume of 18.7 mm³ (IQR, 15.8-24.7). No infarct lesions were observed in sham-operated animals. Infarct volume was not significantly correlated with neurological deficit score. COMPARISON WITH EXISTING METHODS:Unlike conventional microsphere- or thrombus-based embolic models that typically require cervical vessel exposure and direct arterial injection, this method enables minimally invasive, fluoroscopy-guided, selective embolic delivery with angiographic monitoring and dose standardization based on catheter geometry and sediment length. CONCLUSIONS:This model provides a reproducible translational platform for studying microembolic brain injury and evaluating preventive or therapeutic strategies.
BACKGROUND:Digital light processor (DLP)-based patterned illumination enables targeted optogenetic stimulation with high speed and flexibility. While these systems are routinely characterized by optical contrast and spatial resolution, the functional impact of residual light leakage on biological samples remains frequently overlooked. Establishing thresholds and mitigation strategies for this unintended illumination is essential for ensuring the reliability and precision of targeted photostimulation assays. NEW METHOD:We quantitatively characterized parasitic illumination in a standard DLP-based microscopy setup and evaluated its functional impact on ChR2-expressing neuronal cultures, ranging from subthreshold depolarization to downstream effects on network-level plasticity. Leakage intensities were measured across multiple system configurations and correlated with neuronal responses using calcium imaging and immunostaining of activity-dependent synaptic markers. RESULTS:The intrinsic DLP black-level emission and back-reflections at the sample plane were identified as the dominant leakage sources, and mitigation strategies were suggested. Functional assays showed that leakages below 50 μW/mm2 induce detectable calcium responses without triggering synaptic strengthening, whereas higher intensities can drive spiking, alter network dynamics, and promote synaptic potentiation. COMPARISON WITH EXISTING METHODS:Previous studies characterizing DLP-based optogenetic systems did not focus on the physiological effects induced by parasitic light with illumination intensities below the conventional ChR2 activation threshold. CONCLUSION:These findings establish thresholds for unintended optogenetic stimulation and provide a simple framework for mitigating parasitic illumination in DLP-based patterned-light optogenetic systems, thereby improving the precision and reliability of targeted photostimulation.
BACKGROUND:Behavioral pharmacological studies in rats and mice often measure behavioral responses to ethanol or other drugs administered by injection, such that the timing of the injection provides a convenient point of reference to index the effects of the drug. Although a variety of drug administration protocols have been developed for use with the fruit fly Drosophila melanogaster, currently available techniques do not allow for a comparable bolus administration of drugs to awake, behaving flies. NEW METHOD:We developed a novel apparatus that temporarily restrains and orients unanesthetized fruit flies for an intra abdominal injection. Using this apparatus, we injected male and female flies with a constant 200 nL volume of ethanol at varying concentrations (0-50% v/v), then measured acute and protracted behavioral changes as well as survivability following the injections. RESULTS:Ethanol produced an acute biphasic effect on locomotor activity and dose-dependent increase in immobility as measured by a loss-of-righting response assay, with no significant differences by sex. A protracted, sex-dependent effect of ethanol injection was also found on the rate of locomotion measured before exposure to ethanol vapor, with male flies showing increased locomotion when measured 28 h after injection. COMPARISON WITH EXISTING METHODS:Ethanol-related behaviors following injections resemble those produced by vapor exposure. However, poor survivability after the injection will likely limit the procedure to studies of acute drug responses. CONCLUSION:Our results suggest that this injection procedure might prove useful for characterizing ethanol and drug responses in fruit flies.
BACKGROUND:Early diagnosis of neurological dysfunctions, particularly epilepsy, is vital for early intervention and improvement of patients' quality of life. However, traditional seizure detection techniques suffer from low detection accuracy, high false positive rate, and high computational complexity, making it difficult to effectively capture the complex spatiotemporal characteristics of electroencephalography (EEG) signals. Despite the significant improvements in seizure detection accuracy brought by deep learning techniques, the current models suffer from inaccuracies, limited adaptability, and inability to operate in real time. NEW METHOD:To address these challenges, a new hybrid deep learning model based on one-dimensional Convolutional Neural Network (1D-CNN), Bidirectional Long Short-Term Memory (BiLSTM) network and Dueling Q-Learning is proposed to accurately classify epileptic seizures from EEG signals in an adaptive manner. In addition, a novel approach is proposed called Metaheuristic Based Adaptive Optimization (MBAO) to adaptively select an optimal temporal window size for the effective extraction of features, while minimizing the required information loss and computation burden. RESULTS:and Comparison with existing methods: The proposed model has tested in various experiments conducted in a large number of benchmark datasets like CHB-MIT, Kaggle EEG Epileptic datasets etc. which justifies the effectiveness of the proposed model. DuelQ-SeizureNet has an accuracy of 99%, a precision of 96%, a recall (sensitivity) of 98%, a specificity of 99%, and an F1 score of 99% with a low execution time of 50 ms in seizure prediction. CONCLUSIONS:This proposed framework introduces a novel reinforcement learning assisted optimization approach in deep seizure detection architecture. It can operate with lower false detection rates (1.8%), higher area under the ROC curve (AUC) (0.995), and lower computational speed than the existing scheme, ensuring reliable real-time implementation.
BACKGROUND:In the ongoing search for prognostic tools in neonates suffering perinatal asphyxia, we assessed the feasibility of resting-state functional magnetic resonance imaging (RS-fMRI). The aim of our study was to determine both the intra-session and inter-subject reproducibility of resting-state networks (RSNs), as well as factors affecting these. NEW METHOD:We conducted a prospective multicenter study in 21 asphyxiated term newborns (mean gestational age = 39.2 weeks, mean 5-minute Apgar score = 3) after treatment with controlled hypothermia at a level III neonatal intensive care unit. RSNs were assessed twice with RS-fMRI at 1.5 T using both group MELODIC ICA and single-subject ICA. Intraclass correlation coefficients were calculated on all networks identified from the group MELODIC. Feasibility of the RS-fMRI technique was determined by assessing the ability to discriminate common RSNs, the presence of motion artifacts and the temporal signal to noise ratio. RESULTS:Seven RSNs could be identified, anterior default mode network aDMN), default mode network (DMN), left frontoparietal network (lFPN), right frontoparietal network (rFPN), auditory network (AN), sensorimotor network (SMN), parietal network (ParietalN). Two networks (DMN and rFPN) demonstrated moderate reproducibility (ICC 0.62 and 0.69, respectively). The other networks demonstrated poor reproducibility (ICC <0.5). CONCLUSION:Following perinatal asphyxia, reproducibility was moderate for DMN and rFPN and poor for the other RSNs.
BACKGROUND:Intracarotid drug delivery in rodents is important for investigating neurological disorders and evaluating intra-arterial therapies. However, existing carotid catheterization tools are limited by large catheter size, complicated preparation, catheter instability, vascular injury, and catheter-related mortality, particularly in mice. NEW METHOD:We developed a simple, cost-effective carotid artery catheterization device for rats and mice. The device consists of ultra-fine polypropylene tubing, a 34 G needle, tissue-biocompatible adhesive, and a 1-mL syringe, and is compatible with external infusion pumps for continuous controlled administration. A streamlined protocol was established to reduce technical variability and improve delivery efficiency. RESULTS:The device was evaluated in 35 mice and 24 rats receiving intracarotid PBS administration. One mouse died before catheterization, likely due to anesthesia-related complications; no catheterization-related mortality or major complications occurred. Postoperative recovery was uneventful, with no neurological dysfunction during one-week monitoring. The mean procedural time was 18.9 min in mice and 17.3 min in rats. Evans Blue experiments showed higher brain signal after carotid administration than after tail vein injection. The device was also compatible with the filament-based transient middle cerebral artery occlusion model. COMPARISON WITH EXISTING METHODS:Compared with reported devices, this device has the smallest carotid cannula outer diameter of 0.2 mm, requires less than 5 min for preparation, and offers simple construction, low cost, and improved maneuverability. CONCLUSIONS:This device provides a practical tool for intracarotid drug delivery in rodents and may facilitate central nervous system-targeted research and preclinical evaluation of carotid artery-based therapies.
BACKGROUND:Options for fluorescent myelin stains are limited to immunofluorescent localization of myelin basic protein (MBP) and a proprietary lipid soluble dye, FluoroMyelin, for use with frozen sections and aqueous antifade mounting media. The present Chromate/Fluoro-Jade (Cr/F-J) stain was developed to enable the stable, high contrast and resolution fluorescent labeling of myelin in paraffin processed tissue sections. NEW METHOD:Tissue sections were delipidized, rehydrated and transferred to a warm solution of potassium chromate. They were then stained in a Fluoro-Jade C solution in 45% ethanol, rinsed, solvent dehydrated and cover-slipped with DPX. RESULTS:This stain exhibits the high contrast fluorescent labeling of both large myelinated tracts as well as fine individual myelinated axons. This staining pattern correlated closely with that seen with immunofluorescent labeling using antibodies against MBP. Furthermore, the stain binds to purified MBP in a concentration dependent manner. Omission of the chromium pretreatment abolished all staining as did the substitution of carboxyfluorescein for FJ-C. COMPARISON WITH EXISTING METHODS:Unlike immunofluorescent staining or the use of lipid soluble fluorochromes, advantages of the present method include speed, sensitivity, a lack of fading or diffusion, a disclosed chemical identity, compatibility with paraffin embedded tissue, aqueous or solvent based mounting media and various fluorescent counterstains. CONCLUSION:The Cr/F-J staining procedure can be used for the high contrast and resolution fluorescent labeling of myelinated fibers in paraffin embedded brain tissue sections. It is suitable for multiple labeling studies and can be used to demonstrate both normal and pathological myelin.
BACKGROUND:Monoaminergic systems, as some other neuromodulators, exert modulatory influences across the entire central nervous system (CNS), participating in basic neurobiological processes, behavioural traits, neuropsychiatric diseases, and responses to psychotropic drugs. Their activity is supposedly balanced across the CNS i.e. a change of input in one region could alter their activities at distal regions. Unfortunately, there are a few attempts to determine the neurochemical relationships between local or distal regions. NEW METHOD:In this review article, we present the technical requirements for performing complex analysis of neurochemical, postmortem, quantitative data on neurotransmitter systems. We explore new types of neurochemical analysis beyond quantitative differences to approximate neurochemical connectivity. RESULTS:Although the lack of temporality and unclear meaning of neurotransmitter tissue content are limitations of this approach, postmortem measurement offers the possibility of quantitatively and qualitatively assessing the content of monoamines and/or metabolites in multiple parts of the CNS. This form of neurochemical connectivity is distinct from anatomical connection and brain functional connectivity. COMPARISON WITH EXISTING METHODS:This expands the study of neurotransmitter systems beyond a specific/limited set of brain regions and allows for the description of possible inter-regional influences within a neurotransmitter system and between neurotransmitter systems across the CNS. CONCLUSION:Through this unprecedented discussion, this article advances the use of neurochemical data towards multiple dimensions of analysis, primarily based on monoaminergic systems and their neurochemical connectivity.
