bioRxiv Subject Collection: Neuroscience's Journal

Acute temporal, regional, and cell-type specific NKCC1 disruption following severe TBI in the developing gyrencephalic brain.
Traumatic brain injury (TBI) in children is a leading cause of morbidity and mortality, with no effective treatment and limited clinical management. We developed a multifactorial traumatic brain injury model in piglets which mirrors the evolving pathophysiology of severe pediatric TBI, showing age-dependent hypoxic-ischemic cerebral cortical injury and matrix metalloproteinase-driven vasogenic edema, with infant piglets experiencing less tissue damage than toddler piglets. Extracellular matrix breakdown can precipitate neuronal dysfunction, disrupting chloride homeostasis and the reversal potential for GABA. We hypothesized that ongoing tissue damage might be related to markers of immature GABA, evaluated by changes to the expression and phosphorylation of sodium-potassium-2-chloride cotransporter 1 (NKCC1), potassium-chloride cotransporter 2 (KCC2), and a regulatory kinase, (STE20/SPS1-related proline-alanine-rich protein kinase) SPAK. We mapped these markers in developing swine and infant human brain, identifying a postnatal pNKCC1 decrease in human infant hippocampus, and a perinatal cortical and hippocampal GABA switch in pigs, with no change in the thalamus. In infant piglets with severe TBI, upregulation of neuronal pNKCC1 correlated with hypoxic-ischemic injury and seizure duration. We also observed dysregulation of NKCC1, KCC2, and SPAK in cortex and hippocampus in infant and toddler piglets with severe TBI, with thalamus unchanged. We noted ectopic, non-apical localization of pNKCC1 signal in choroid plexus epithelium across ages in piglets and humans with severe TBI, indicating acute dysregulation of the CSF chloride milieu. These findings position swine as a useful model for pediatric TBI research and suggest that SPAK or NKCC1 inhibition in infants may be therapeutic.

The effects of task similarity during representation learning in brains and neural networks
The complexity of our environment poses significant challenges for adaptive behavior. Recognizing shared structures across tasks can theoretically improve learning through generalization. However, how such shared representations emerge and influence performance remains poorly understood. Contrary to expectations, our findings revealed that individuals trained on tasks with similar low-dimensional structures performed worse than those trained on dissimilar tasks. Magnetoencephalography revealed correlated neural representations in the same-structure group and anticorrelated ones in the different-structure group. Crucially, practice reduced this performance gap and shifted the neural representations of the tasks in the same-structure group towards anticorrelation, like those in the different-structure group. A neural network model trained on similar tasks replicated these findings: tasks with similar structures require more iterations to orthogonalize their representations. These results highlight a complex interplay between task similarity, neural dynamics, and behavior, challenging traditional assumptions about learning and generalization.

The interplay between CB2 and NMDA receptors in Parkinsons disease
Parkinson's disease (PD) is a progressive neurological disorder that affects movement, causing symptoms such as tremors, stiffness, slowness, and balance problems due to the degeneration of dopamine-producing neurons in the brain. Nowadays there is no cure for PD. Alpha synuclein (-syn) aggregates, which are a hallmark of PD, are known to induce microglial activation, specifically the detrimental M1 microglial phenotype, which contributes to neuroinflammation and disease progression. Cannabinoid receptor 2 (CB2R) activation has been shown to counteract neuroinflammation. CB2R is able to interact with NMDA receptors (NMDAR), which has also attracted attention in PD research due to its role in excitotoxicity. Here we aimed to study the interaction between CB2R and NMDAR in a PD context. We observed that -syn fibrils alter CB2R activation and CB2R-NMDAR heteromerization in a heterologous expression system. Furthermore, activation of CB2R counteracted NMDAR signaling. In neurons -syn fibrils decreased CB2R-NMDAR heteromer expression, while increasing CB2R signaling. Importantly, CB2R activation counteracted the -syn fibrils-induced increase in M1 activated microglia, while it favored the polarization of microglia to the beneficial M2 phenotype. These results reinforce the idea of using cannabinoids for treating PD, as they provide not only the anti-inflammatory effects of cannabinoids but also counteract the detrimental increase in NMDAR signaling present in this disease.

Endothelial Sphingosine-1-Phosphate Receptor (S1PR) 1, a Functional S1PR in the Human Cerebrovascular Endothelium, Limits Blood Brain Barrier Permeability and Neuronal Injury following Subarachnoid Hemorrhage in Mice.
Hypoxia-induced blood-brain barrier (BBB) permeability has been identified as a key contributor to the progression of ischemic-hypoxic brain injury and neuronal dysfunction in stroke and other cerebrovascular diseases. Emerging clinical evidence highlights that the vasoprotective signaling properties of high-density lipoprotein (HDL), mediated through its bioactive lipid component sphingosine-1-phosphate (S1P), may be impaired in cardiovascular and inflammatory conditions. Nonetheless, the precise contributions and mechanistic roles of S1P signaling within the cerebral microvasculature remain insufficiently characterized. In this study, we aimed to elucidate the role of S1P signaling via its endothelial receptor S1PR1 in the pathophysiology of early brain injury following subarachnoid hemorrhage (SAH), a particularly severe form of stroke. Additionally, we sought to evaluate the relevance of the endothelial S1PR1 pathway in the human cerebrovascular endothelium, its functional role in hypoxia-induced cerebral endothelial barrier dysfunction, and its underlying molecular mechanisms. To address these objectives, we utilized endothelial-specific S1PR1 knockout mice subjected to the endovascular rupture model of aneurysmal SAH, performed mechanistic studies in primary human cerebral microvascular endothelial cells, and characterized S1PR1 expression in human brain tissue using validated protocols. Our findings reveal robust expression of S1PR1 in the cerebrovascular endothelium of both mice and humans. Functional analyses demonstrated that S1PR1 is critical for maintaining BBB integrity and mitigating neuronal injury in the context of SAH. Mechanistic in vitro studies indicated that S1PR1 exerts a vasoprotective effect by limiting hypoxia-induced BBB dysfunction in human primary brain microvascular endothelial cells through inhibition of Rho-associated kinase (ROCK)-mediated phosphorylation of myosin light chain (MLC), suppression of stress fiber formation and caveolin-1-dependent endosomal trafficking. These results highlight the pivotal role of endothelial S1PR1 signaling in preserving cerebral vascular integrity and provide a strong scientific foundation for developing novel therapeutic approaches targeting the S1P pathway in the endothelium to enhance neurovascular protection.

Neuropeptidergic circuit modulation of developmental sleep in Drosophila
Sleep-wakefulness regulation dynamically evolves along development in flies, fish, and humans. While the mechanisms regulating sleep in adults are relatively well understood, little is known about their counterparts in early developmental stages. Here, we report a neuropeptidergic circuitry that modulates sleep in developing Drosophila larvae. Through an unbiased screen, we identified the neuropeptide Hugin and its receptor PK2-R1 as critical regulators of larval sleep. Our data suggest that HugPC neurons secrete Hugin peptides to activate insulin-producing cells (IPCs), which express a Hugin receptor PK2-R1. IPCs, in turn, release Drosophila insulin-like peptides (Dilps) to regulate sleep. We further show that the Hugin/PK2-R1 axis is dispensable for adult sleep control. Our findings thus reveal the neuromodulatory circuitry regulating larval sleep, highlighting differential impacts of the same modulatory axis on developmental sleep and adult sleep.

Diversity in the impact of heterogeneities on recurrent networks performing a cognitive task
Background and motivation: Artificial recurrent networks are widely used as models to study the complex dynamics underlying biological neural networks during execution of cognitive tasks. However, most studies assume individual units in the recurrent network to be homogeneous repeating units, whereas real neurons exhibit several forms of heterogeneities. In this study, we designed and employed a systematic framework for quantitative assessment of the impact of neural heterogeneities on recurrent networks that were trained to perform a cognitive task. Methodology: Our framework involved training of a population of recurrent networks, differing in terms of their hyperparameters, to perform a cognitive task in the presence of six graded levels of intrinsic heterogeneities. We tested the impact of heterogeneities on several performance metrics that encompassed training performance, task-execution dynamics, and resilience to different forms of post-training heterogeneities (also introduced at different levels. Results: Our population-of-networks approach demonstrate that intrinsic heterogeneities impacted network performance and dynamics in diverse ways even if they were trained with the same training algorithm, convergence criteria, and task specifications. First, our analyses unveiled pronounced network-to-network variability in the dependence of training performance on the level of heterogeneity, in terms of the number of training trials required for learning and the error values associated with task performance. Second, the impact of training heterogeneities on network dynamics during task execution also manifested substantial variability across networks. Finally, our analyses revealed a prominent impact of different forms of post-training heterogeneities on performance errors and network dynamics. We observed progressive increases in errors as well as in trajectory deviations with graded increases in post-training heterogeneities. Importantly, we observed pronounced variability in how robustness to post-training heterogeneities depended on the level of training heterogeneities. Specifically, certain networks showed enhanced robustness to post-training heterogeneities when training heterogeneities were low, whereas others showed better robustness when training heterogeneities were high. Implications: The striking nature of network-to-network variability observed in our analyses strongly advocates a complex systems viewpoint to study the impact of neural heterogeneities on circuit function. Within such a complex system framework, where several functionally specialized subsystems interact with each other in non-random ways to yield collective performance of the task, we argue that the emphasis should not be on heterogeneities in individual components of neural circuits. Instead, we emphasize the need to focus on the global structure of different forms and degrees of heterogeneities across different components and a systematic assessment of how they interact with each other towards adapting and achieving collective function.

High intensity exercise before sleep boosts memory encoding the next morning
The importance of sleep for memory consolidation has been extensively studied, but its role for memory encoding remains less well characterized. At the molecular and cellular level, the renormalization of synaptic weights during sleep has received substantial support, which is thought to free capacity to encode new information at the behavioral level. However, at the systems level and behaviorally, support for this process playing a major role for memory function remains scarce. In the current study, we investigated the utility of moderate- and high-intensity evening exercise as a low-cost low-tech intervention to modulate sleep and its influence on subsequent encoding in the morning. Our findings indicate that high-intensity interval training (HIIT) improved post-sleep memory performance with effects lasting up to 24 hours after initial encoding. In addition, we show that especially the early parts of the encoding task were affected by the HIIT intervention, which is in line with increases in synaptic homeostasis being targeted by the exercise. Intriguingly, low-performing participants seemed to benefit more from the HIIT intervention suggesting it not only as a tool for basic research but also as a candidate for applications to boost memory performance in mental disorders or in the elderly. These results provide first evidence that acute exercise can affect learning processes even hours after it occurs.

A formal model of anxiety disorders based on the neural circuit dynamics of the fear and extinction circuits
The pathophysiology of anxiety disorders is the outcome of an imbalance of the fear-anxiety circuit and the extinction circuit. We present a formal model using nonlinear dynamics and network theory, which captures the dynamic interactions of the key nodes of the anxiety and extinction networks. This rudimentary model can be modified by newer data. These core nodes consist of the cells of the paraventricular nucleus of the thalamus coding negative valence, the neurons of the basal-lateral amygdala coding negative valence (Rspo2+), the anterior cingulate cortex, the ventral hippocampus neurons coding fear memories, the somatostatin expressing cells of the lateral segment of the central amygdala, the medial segment of the central nucleus of the amygdala-bed nucleus of the stria terminalis and their target nodes. The extinction network consists primarily of the paraventricular thalamic cells coding positive valence, (Ppp1r1b+) cells of the basolateral amygdala coding positive valence, the ventromedial prefrontal cortex, the PKC{delta} cells of the lateral segment of the central amygdala, and the intercalated cells. Human and non-human animal genetic and epigenetic studies point to deficiencies in brain-derived neurotrophic factor and neurotrophic receptor kinase tyrosine 2 production in key nodes causing reduced plasticity extinction network plasticity and leading to a weakened extinction response. We rely primarily on the neurophysiological studies of non-human animal models since nodes generating fear/anxiety and extinction responses are highly conserved across species and equivalent nodes are present within analogous circuits of the human brain. The results are confirmed, where possible by human functional magnetic resonance imaging studies. We believe this simplified model is of heurist value and can lead to a more consistent focus on physiologically based pathophysiology. This would lead to treatments to reverse the pathologic physiology produced by genetic and epigenetic abnormalities, and greater efforts to directly correct pathologic circuit activity through direct interventions such as transcranial magnetic stimulation.

A cholinergic spinal pathway for the adaptive control of breathing
The ability to amplify motor neuron (MN) output is essential for generating high intensity motor actions. This is critical for breathing that must be rapidly adjusted to accommodate changing metabolic demands. While brainstem circuits generate the breathing rhythm, the pathways that directly augment respiratory MN output are not well understood. Here, we mapped first-order inputs to phrenic motor neurons (PMNs), a key respiratory MN population that initiates diaphragm contraction to drive breathing. We identified a predominant spinal input from a distinct subset of genetically-defined V0C cholinergic interneurons. We found that these interneurons receive phasic excitation from brainstem respiratory centers, augment phrenic output through M2 muscarinic receptors, and are highly activated under a hypercapnia challenge. Specifically silencing cholinergic interneuron neurotransmission impairs the breathing response to hypercapnia. Collectively, our findings identify a novel spinal pathway that amplifies breathing, presenting a potential target for promoting recovery of breathing following spinal cord injury.

Lysosomal Glucocerebrosidase is needed for ciliary Hedgehog signaling: A convergent pathway to Parkinsons disease
Mutations in LRRK2 and GBA1 are the most common genetic causes of familial Parkinsons disease. Previously, we showed that pathogenic LRRK2 mutations inhibit primary cilia formation in rare interneurons and astrocytes of the mouse and human dorsal striatum. This blocks Hedgehog signaling and reduces synthesis of neuroprotective GDNF and NRTN, which support neurons vulnerable in PD. Here we show that GBA1 mutations also impair Hedgehog signaling through a distinct mechanism. Loss of GBA1 activity decreases accessible cholesterol in primary cilia of cultured cells, thereby disrupting Hedgehog signaling. In the mouse striatum, Gba1 mutations result in reduced Hedgehog-induced Gdnf RNA expression in cholinergic interneurons, despite having no detectable impact on cilia formation. Also, both Lrrk2 and Gba1 mutations suppress Hedgehog-induced Bdnf expression in striatal astrocytes. These findings underscore the role of Hedgehog signaling in the nigrostriatal circuit and reveal a convergent mechanism by which distinct mutations may contribute to PD pathogenesis.

Estimating the motor exploration in reinforcement learning
What motor exploration strategies do animals use to learn a skill from rewards? Reinforcement learning theory provides no guidance for estimating motor exploration - the behavioral component aimed at discovering better strategies. Inspired by the brain's modular organization, we postulate a latent learner that explores via an additive source of ideal randomness it injects into behavior. Assuming the learner is ignorant of other motor components, which is sub-optimal by design, evolutionary fitness argues that these should display mainly non-ideal variability. We test this recipe for behavior decomposition in songbirds subjected to a vocal pitch conditioning task. The explorative component we estimate from vocalizations accounts for the motor contribution of a basal ganglia pathway and the other behavioral component accounts for birds' suboptimal learning trajectories. This congruence between normative exploration and brain organization suggests that the evolutionary pressure for behavioral optimality is lesser than to learn from purely random trials.

Sound-Enhanced Sleep Depth Reduces Traumatic Brain Injury Damage and Sequelae and Supports Microglial Response
Traumatic brain injury significantly reduces the quality of life for millions of survivors worldwide, with no established treatments currently available. High slow-wave activity (SWA) sleep immediately after rodent TBI improves posttraumatic outcomes. However, pharmacological SWA-enhancing strategies are hindered by severe specificity and scalability issues that prevent it from effectively reaching clinical implementation. Alternatively, closed-loop auditory stimulation (CLAS) of sleep slow waves offers specific SWA enhancement with high translational potential. Our present results demonstrate that up-phase-targeted CLAS (upCLAS)-mediated SWA enhancement reduced diffuse axonal injury, decreased demyelination, and preserved cognitive ability in TBI rats. The alleviated posttraumatic phenotype was associated with increased microglia response, likely mediating CLAS' neuroprotective effect in the acute injury phase. Auditory-enhanced SWA may thus constitute a novel noninvasive neuroprotective therapy preventing TBI sequelae via boosted cellular response to tissue damage.

Daily intermittent fasting is an effective multiscale treatment in preclinical models of absence epilepsy
Absence epilepsy (AE) is characterized by brief but frequent seizures with loss of consciousness. Existing treatments have heavy side effects, are only partially effective and do not address the comorbidities, including cognitive and social deficits. A tripartite link between seizures, cognitive deficits and diet has been established. We focused on intermittent fasting (IF), a regime where daily periods of fasting alternate with periods of food intake, with no restrictions in the type or quantity of food consumed. To date, the effects of IF on infantile epilepsy have not been addressed. We evaluated the therapeutic potential of a daily, one-month protocol of IF on three established mouse models of AE: the Grm7AAA KI mouse, the Scn2a haploinsufficiency mouse and the pharmacologically-induced AY-9944 mouse model. We show a reduction of the seizure frequency in all models, as well as an improvement of the sociability deficits observed in two of the models, with no adverse effects. Focusing on the Grm7AAA KI model, we performed RNA sequencing in a one of the key brain areas of the absence seizure circuit, the thalamus. We detected a deregulation of genes involved in vascularization associated with the development of malformed blood vessels in epileptic mice. Along with its anti-seizure effects, IF was able to counteract both abnormal gene expression and vessel morphology. This study demonstrates for the first time the positive effects of IF on AE and could facilitate the implementation of the diet in clinical trials.

Nose-to-Brain Healing: Hypoxia-Preconditioned Mesenchymal Stem Cells Prompt Recovery in Hypoxic-Ischemic Encephalopathy Rats
Neonatal HIE poses a significant risk factor for neurodevelopment impairment. Therapeutic hypothermia, the current standard of care for this condition, has several constraints and reduced effectivity, especially in more severe cases. Thus, it is necessary to explore novel therapeutics, like MSCs. Although previous studies report that administration of MSCs (from different sources) prompted the recovery of HIE-lesioned animals, high doses are currently used. First, this study compared the efficacy of IN versus IV administration of 50,000 UC-MSCs in a rat model of neonatal HI brain injury. For this cell dose, only IN-UC-MSC therapy reduced infarct volume, an effect accompanied by improvements of motor skills and recognition memory. Also, IN-UC-MSC administration restored myelination in the corpus callosum and mitigated glial reactivity more effectively than IV administration. In a second part of the study, to potentiate the effect of UC-MSCs administration, postnatal rats that underwent HI injury received 25,000 hypoxia-preconditioned UC-MSCs or its secretome two days later, via IN route. The administration of a low-dose of hypoxia-preconditioned UC-MSCs was sufficient to induce neurological recovery and modulation of glial response. Moreover, the administration of the secretome of these cells was enough to induce the same extent of recovery. These findings support the higher potential of IN-UC-MSC administration, compared to IV administration, while enhancing our understanding of hypoxia-preconditioning and the role of the secretome derived from UC-MSCs in driving a positive therapeutic response, contributing to the development of more effective and feasible treatments for neonatal HIE.

GAL-101 prevents amyloid beta-induced membrane depolarization in two different types of retinal cells
Glaucoma and age-related macular degeneration (AMD) are two of the major causes of progressive vision loss and ultimately blindness worldwide. Both retinopathies share several pathological features with Alzheimer's disease (AD) such as: impairment of neuronal function, astrocytosis, and activation of immune-competent microglia and Mueller cells. It also has been shown that these conditions are characterized by the presence of an elevated concentration of amyloid beta (Abeta). Under pathological conditions, Abeta1-42 tends to aggregate, forming toxic soluble oligomers, considered to be the most harmful amyloid species. One strategy adopted to prevent cell damage caused by these oligomers is to impair their aggregation. Here we studied GAL-101, a small molecule designed to modify the aggregation of Abeta1-42. To assess the role of GAL-101 in the aggregation of Abeta1-42, in vitro electrophysiological measurements on retinal ganglion cells (RGCs) and retinal pigment epithelial (RPE) cells were performed to determine the polarization of the resting membrane potential. Cells treated only with Abeta1-42 oligomers showed a strong depolarization of the resting membrane potential, which is believed to be the main reason for retinal cells malfunctioning in neurodegenerative diseases of the eye. Pre-incubation with GAL-101 stabilized the cell resting potential to around -50mV during exposure to Abeta1-42, in both RGCs and RPE cells. GAL-101 was able to prevent changes in resting membrane potential and thus would be expected to prevent impairment of retinal cell function. These results are supportive of evaluating GAL-101 as a potential treatment of Abeta-associated retinopathies like glaucoma and dry AMD.

DNA methylation as a contributor to dysregulation of STX6 and other frontotemporal lobar degeneration genetic risk-associated loci
Frontotemporal Lobar Degeneration (FTLD) represents a spectrum of clinically, genetically, and pathologically heterogeneous neurodegenerative disorders characterised by progressive atrophy of the frontal and temporal lobes of the brain. The two major FTLD pathological subgroups are FTLD-TDP and FTLD-tau. While majority of FTLD cases are sporadic, there also exists heterogeneity within the familial cases, typically involving mutations in MAPT, GRN or C9orf72, which is not fully explained by known genetic mechanisms. We sought to address this gap by investigating the effect of epigenetic modifications, specifically DNA methylation variation, on genes associated with FTLD genetic risk in different FTLD subtypes. We compiled a list of genes associated with genetic risk of FTLD using text-mining databases and literature searches. Frontal cortex DNA methylation profiles were derived from three FTLD datasets containing different subgroups of FTLD-TDP and FTLD-tau: FTLD1m (N = 23) containing FTLD-TDP type A C9orf72 mutation carriers and TDP Type C sporadic cases, FTLD2m (N = 48) containing FTLD-Tau MAPT mutation carriers, FTLD-TDP Type A GRN mutation carriers, and FTLD-TDP Type B C9orf72 mutation carriers and FTLD3m (N = 163) progressive supranuclear palsy (PSP) cases, and corresponding controls. To investigate the downstream effects of DNA methylation further, we then leveraged transcriptomic and proteomic datasets for FTLD cases and controls to examine gene and protein expression levels. Our analysis revealed shared promoter region hypomethylation in STX6 across FTLD-TDP and FTLD-tau subtypes, though the largest effect size was observed in the PSP cases compared to controls (delta-beta = -32%, adjusted-p value=0.002). We also observed dysregulation of the STX6 gene and protein expression across FTLD subtypes. Additionally, we performed a detailed examination of MAPT, GRN and C9orf72 in subtypes with and without the presence of the genetic mutations and observed nominally significant differentially methylated CpGs in variable positions across the genes, often with unique patterns and downstream consequences in gene/protein expression in mutation carriers. We highlight the contribution of DNA methylation at different gene regions in regulating the expression of genes previously associated with genetic risk of FTLD, including STX6. We analysed the relationship of subtypes and presence of mutations with this epigenetic mechanism to increase our understanding of how these mechanisms interact in FTLD.

Quieting the Storm: Hypoxia as a Strategy to Boost UC-MSC Therapies for Neonatal Hypoxic-Ischemic Encephalopathy
Integrating stem cell therapies into clinical settings faces several challenges, particularly in achieving the high cell yields necessary for attaining therapeutic doses. Preconditioning with hypoxic conditions has shown promise in enhancing the UC-MSCs reparative capabilities of the central nervous system. Recent evidence suggests that oxygen concentration and exposure duration can shape MSCs' phenotypes, supporting the need for further optimization of this strategy in a way to achieve maximal repair. In this study, we assessed the effects of both prolonged mild hypoxia (MH; 5% oxygen for 48 hours) and short severe hypoxia (SSH; 0.1% oxygen for 24 hours) on UC-MSCs' ability to alleviate motor and cognitive deficits in a rodent model of neonatal HIE. Our results show that short, severe hypoxia led to more improvements in functional recovery than prolonged mild hypoxia, supporting that specific preconditioning parameters are crucial in maximizing UC-MSC therapeutic potential. To investigate the molecular effects of hypoxia-preconditioned MSCs in the neonatal brain post-HIE, we employed untargeted proteomics on ipsilesional brain samples from control, HIE, HIE treated with naive UC-MSCs, and HIE treated with SSH-preconditioned UC-MSCs groups, 30 days after lesion induction. This approach identified protein signatures related to injury and therapeutic intervention. Pathway enrichment analysis further revealed that administration of UC-MSCs preconditioned with short severe hypoxia significantly impacted neural signaling, protein synthesis, and energy metabolism pathways, pointing to long-term mechanisms that may support neuronal repair. These findings enhance our understanding of hypoxia-preconditioning in MSCs therapy in driving a positive therapeutic response, supporting the development of more effective and feasible treatments for neonatal HIE.

Type-I nNOS neurons orchestrate cortical neural activity and vasomotion
It is unknown how the brain orchestrates coordination of global neural and vascular dynamics. We sought to uncover the role of a sparse but unusual population of genetically-distinct interneurons known as type-I nNOS neurons, using a novel pharmacological strategic to unilaterally ablate these neurons from the somatosensory cortex of mice. Region-specific ablation produced changes in both neural activity and vascular dynamics, decreased power in the delta-band of the local field potential, reduced sustained vascular responses to prolonged sensory stimulation, and abolished the post-stimulus undershoot in cerebral blood volume. Coherence between the left and right somatosensory cortex gamma-band power envelope and blood volume at ultra-low frequencies was decreased, suggesting type-1 nNOS neurons integrate long-range coordination of brain signals. Lastly, we observed decreases in the amplitude of resting-state blood volume oscillations and decreased vasomotion following the ablation of type-I nNOS neurons. This demonstrates that a small population of nNOS-positive neurons are indispensable for regulating both neural and vascular dynamics in the whole brain and implicates disruption of these neurons in diseases ranging from neurodegeneration to sleep disturbances.