Individual Spines Research Articles

Redescription of Chrysosphaerella baikalensis (Chrysophyceae, Chromulinales) with new data on the ultrastructure of its stomatocysts

An amended description of the ultrastructure of plate and spine scales is provided, along with the first description of the stomatocyst Chrysosphaerella baikalensis from Lake Baikal. C. baikalensis exhibits four types of plate scales: small and large elliptical, large rounded, and large subcircular scales. The spines can grow up to 47 μm in length. The stomatocysts of C. baikalensis are spherical or slightly oblate, with a small, regular pore surrounded by a flat pseudoanulus, lacking a collar. Based on their surface ornamentation, two forms of stomatocysts are distinguished, Forma A covered with densely arranged short needle-like outgrowths and Forma B having a smooth to psilate surface. We associate the first form with the immature stage. In this article, we report the growth of C. baikalensis in Lake Baikal during June, in the open water period, at a water temperature of 3.9–4.5 °C. During this period, whole cells and stomatocysts covered with plate scales were observed. Individual spines and plate scales were found at temperatures up to 11.5 ℃.

Effects of lower back foam rolling on the pressure pain threshold and the range of motion of the lumbar spine in healthy individuals.

The aim of this study was to determine the short- and long-term effects of foam rolling (FR) on the pressure pain threshold and the range of motion of the lumbar spine in healthy subjects. 43 healthy subjects without back problems were randomly assigned to an experimental group (EG) or a control group (CG). The subjects in the EG underwent a 4-week FR program (12 sessions). The subjects in the CG received no intervention. Range of motion was measured using the modified-modified Schober test for flexion and fingertip-to-floor distance for lateral flexion. The pressure pain threshold was measured with a hand-held pressure algometer. The measurements were taken before and after the first FR, after the 4-week program and at the 1-, 3- and 6-month follow-up. The significance level was set at p ≤ 0.05 and the desired power of the test was 92%. We found an improvement in flexion (p = 0.03) and lateral flexion (p < 0.001) in the EG after the first FR and recorded a significant improvement in all measured variables (flexion, lateral flexion and algometry: p < 0.001) at the end of the entire 4-week program. The effects were noticeable up to 6 months after the end of the program (p ≤ 0.03) and were statistically significantly better than in the CG (p ≤ 0.04). The calculated Cohen's d value was 1.15 for flexion, 1.06 for lateral flexion and 0.98 for algometry, which represents a large effect size. FR improves the pressure pain threshold and mobility of the lumbar spine in healthy subjects. The effects are noticeable at least 6 months after the end of an FR program.

First records of abnormal fishes in the Arctic and possible reasons of the anomalies

External anomalies in fish are diverse and include abnormal development of external organs (eyes, jaws, fins, etc.), deformity and curvature of the trunk, discoloration of the skin, reversal of the sides (in flounders) and others that reduce the survival of individuals with such disorders. Although they are not uncommon in nature, reports of fish anomalies in Arctic seas are extremely rare. There have been no published records of anomalous Bering flounder Hippoglossoides robustus or polar cod Boreogadus saida. We document here for the first time on albinism, ambicoloration, reversal of the sides, or curved spine in individuals of Bering flounder, as well as a specimen of polar cod with a vertebral deformity captured in the western Chukchi Sea. Photographs of both normal and abnormal individuals are provided. We hypothesize that of all the possible causes of the anomalies we have found, the most likely is the recent dramatic warming in the Arctic.

Dendritic spine head diameter predicts episodic memory performance in older adults.

Episodic memory in older adults is varied and perceived to rely on numbers of synapses or dendritic spines. We analyzed 2157 neurons among 128 older individuals from the Religious Orders Study and Rush Memory and Aging Project. Analysis of 55,521 individual dendritic spines by least absolute shrinkage and selection operator regression and nested model cross-validation revealed that the dendritic spine head diameter in the temporal cortex, but not the premotor cortex, improved the prediction of episodic memory performance in models containing β amyloid plaque scores, neurofibrillary tangle pathology, and sex. These findings support the emerging hypothesis that, in the temporal cortex, synapse strength is more critical than quantity for memory in old age.

THE ASSOCIATION BETWEEN INDIVIDUAL LUMBAR INTERVERTEBRAL DISC DEGENERATION FEATURES AND LOW BACK PAIN IS MODIFIED BY GENETIC PROPENSITY TO PAIN

BackgroundThe association between lumbar intervertebral disc degeneration (LDD) and low back pain (LBP) is modest. We have recently shown that genetic propensity to pain is an effect modifier of the LDD-LBP relationship when LDD is defined as a summary score of LDD (LSUM), suggesting the association may be driven by individuals with the greatest genetic predisposition to pain. This study examined the association between individual spine magnetic resonance imaging (MRI)-determined LDD features and LBP in subgroups defined by genetic predisposition to pain.MethodWe developed a polygenic risk score (PRS) for “genetic propensity to pain” defined as the number of non-back pain locations (head, face, neck/shoulder, stomach/abdomen, hip, and knee) with duration ≥3 months in 377,538 UK Biobank participants of European ancestry. This PRS was used to stratify TwinsUK MRI samples (n=645) into four strata of genetic propensity to pain. We examined the association between LBP and MRI features of lumbar disc height, disc signal intensity, disc bulge, and osteophytes with adjustments for age, sex, PRS strata, interaction terms for each MRI feature x PRS strata, and twin status.ResultsWe found significant effect modification of the LDD-LBP relationship by genetic propensity to pain for the lumbar MRI features of disc height (p=0.03 for the interaction term with highest quartile of genetically-predicted propensity to pain) and disc signal intensity (p=0.001), but not for disc bulge and osteophytes.ConclusionGenetic propensity to pain modifies the association between individual LDD features and LBP and should be considered in LBP clinical studies.Conflicts of interestNo conflicts of interestSources of fundingNo funding obtainedAcknowledgementUKBB data were obtained under the project #18219This paper is submitted to the Spine journal and is under review.

3D Genial Tubercle Anatomic Considerations in Genioglossus Advancement Surgery.

To qualitatively describe variation in morphology of the genial tubercle and quantify the spatial relationship between the tubercle and genioglossus muscle. Case series. Cadaver dissection. Segmental sections of the mandible, with muscular attachments intact, were harvested from 18 fresh cadaver heads. Three-dimensional laser scans, with a resolution of 0.025 mm, were taken of each specimen with muscle attached and repeated after muscle removal. The genioglossus muscular attachment was measured relation to bony landmarks. The morphology of the genial tubercle varied, with anywhere from 1 large spine to 4 individual spines. However, all specimens had a distinguishable superior portion of the tubercle, where the genioglossus attached, and an inferior portion, where the geniohyoid attached. The height of the superior tubercle (ST) was 6.1 mm (95% confidence inerval [CI]: 5.7-6.5). The height of the genioglossus muscle above the peak amplitude of the ST was 4.3 mm (3.8-4.9), but only 2.5 mm (2.0-3.0) below. On average, 64.4% (58.6-70.2) of the height of the genioglossus muscle attachment was above the peak. Overall, 19.5% (14.1-25.0) of the muscle surface area extended beyond the boundaries of the tubercle. The genioglossus muscle attachment originates from the superior genial tubercle, which has a variable topography and amplitude. However, the muscle is not centered on the spines-more of the muscular fibers attach above the spine as compared to below. This new data may explain the genioglossus advancement "miss rate"-failure to advance muscle on initial osteotomy-of 39-78% reported in the literature.

A synapse-specific refractory period for plasticity at individual dendritic spines.

How newly formed memories are preserved while brain plasticity is ongoing has been a source of debate. One idea is that synapses which experienced recent plasticity become resistant to further plasticity, a type of metaplasticity often referred to as saturation. Here, we probe the local dendritic mechanisms that limit plasticity at recently potentiated synapses. We show that recently potentiated individual synapses exhibit a synapse-specific refractory period for further potentiation. We further found that the refractory period is associated with reduced postsynaptic CaMKII signaling; however, stronger synaptic activation only partially restored the ability for further plasticity. Importantly, the refractory period is released after one hour, a timing that coincides with the enrichment of several postsynaptic proteins to pre-plasticity levels. Notably, increasing the level of the postsynaptic scaffolding protein, PSD95, but not of PSD93, overcomes the refractory period. Our results support a model in which potentiation at a single synapse is sufficient to initiate a synapse-specific refractory period that persists until key postsynaptic proteins regain their steady-state synaptic levels.

Repeated diagnostic ultrasound exposure modifies the structural properties of CA1 dendrites and alters the hippocampal transcriptome

The development of neurons is regulated by several spatiotemporally changing factors, which are crucial to give the ability of neurons to form functional networks. While external physical stimuli may impact the early developmental stages of neurons, the medium and long-term consequences of these influences have yet to be thoroughly examined. Using an animal model, this study focuses on the morphological and transcriptome changes of the hippocampus that may occur as a consequence of fetal ultrasound examination. We selectively labeled CA1 neurons of the hippocampus with in-utero electroporation to analyze their morphological features. Furthermore, certain samples also went through RNA sequencing after repetitive ultrasound exposure. US exposure significantly changed several morphological properties of the basal dendritic tree. A notable increase was also observed in the density of spines on the basal dendrites, accompanied by various alterations in individual spine morphology. Transcriptome analysis revealed several up or downregulated genes, which may explain the molecular background of these alterations. Our results suggest that US-derived changes in the dendritic trees of CA1 pyramidal cells might be connected to modification of the transcriptome of the hippocampus and may lead to an increased dendritic input.

In-vivo 3-dimensional spine and lower body gait symmetry analysis in healthy individuals

BackgroundNumerous research studies have delved into the biomechanics of walking, focusing on the spine and lower extremities. However, understanding the symmetry of walking in individuals without health issues poses a challenge, as those with normal mobility may exhibit uneven movement patterns due to inherent functional differences between their left and right limbs. The goal of this study is to examine the three-dimensional kinematics of gait symmetry in the spine and lower body during both typical and brisk overground walking in healthy individuals. The analysis will utilize statistical methods and symmetry index approaches. Furthermore, the research aims to investigate whether factors such as gender and walking speed influence gait symmetry. MethodsSixty young adults in good health, comprising 30 males and 30 females, underwent motion capture recordings while engaging in both normal and fast overground walking. The analysis focused on interlimb comparisons and corresponding assessments of side-specific spine and pelvis motions. ResultsStatistical Parametric Mapping (SPM) predominantly revealed gait symmetries between corresponding left and right motions in the spine, pelvis, hip, knee, and ankle during both normal and fast overground walking. Notably, both genders exhibited asymmetric pelvis left-right obliquity, with women and men showing an average degree of asymmetry between sides of 0.9 ± 0.1° and 1.5 ± 0.1°, respectively. Furthermore, the analysis suggested that neither sex nor walking speed appeared to exert influence on the 3D kinematic symmetry of the spine, pelvis, and lower body in healthy individuals during gait. While the maximum normalized symmetry index (SInorm) values for the lower thorax, upper lumbar, lower lumbar, pelvis, hip, knee, and ankle displayed significant differences between sexes and walking speeds for specific motions, no interaction between sex and walking speed was observed. SignificanceThe findings underscore the potential disparities in data interpretations between the two approaches. While SPM discerns temporal variations in movement, these results offer valuable insights that may enhance our comprehension of gait symmetry in healthy individuals, surpassing the limitations of straightforward discrete parameters like the maximum SInorm. The information gleaned from this study could serve as reference indicators for diagnosing and evaluating abnormal gait function.

Life and death in the Roman period Pula – A bioanthropological analysis of human skeletal remains from the Ozad Arene site

Human skeletal and dental remains are the primary focus of bioarchaeological research, as different diseases and pathological conditions can leave marks on the bones and teeth. Study of these remains provides insights into the lifestyle, health and quality of life of past populations. In this paper, the human skeletal remains from the Ozad Arene archaeological site in Pula (Istria, Croatia), originating from 25 graves and four bone assemblages dated between the 1st and the 4th centuries CE, were analysed. The aim of the paper is to reconstruct demographic and pathological characteristics of the Roman period population from Pula to gain insight into the living conditions and the quality of life in this community, and to determine whether the site differs from other archaeological sites from the same period in terms of general health and living conditions. The human skeletal sample in question comprises skeletal remains of a minimum 48 individuals; the high subadult mortality rate and high prevalence of dental enamel hypoplasia and the presence of cribra orbitalia, porotic hyperostosis, and periostitis indicate overall poor living conditions and widespread metabolic stress during childhood in Pula. Vertebral osteoarthritis and Schmorl′s nodes in the spines of younger individuals suggest continuous hard labour and strenuous physical activity. Based on the available data, it seems that living conditions in the Roman period Pula did not differ significantly from other Roman sites on the eastern Adriatic coast.

Finite Element Analysis of Stress Distribution and Range of Motion in Discogenic Back Pain.

Precise knowledge regarding the mechanical stress applied to the intervertebral disc following each individual spine motion enables physicians and patients to understand how people with discogenic back pain should be guided in their exercises and which spine motions to specifically avoid. We created an intervertebral disc degeneration model and conducted a finite element (FE) analysis of loaded stresses following each spinal posture or motion. A 3-dimensional FE model of intervertebral disc degeneration at L4-5 was constructed. The intervertebral disc degeneration model was created according to the modified Dallas discogram scale. The von Mises stress and range of motion (ROM) regarding the intervertebral discs and the endplates were analyzed. We observed that mechanical stresses loaded onto the intervertebral discs were similar during flexion, extension, and lateral bending, which were greater than those occurring during torsion. Based on the comparison among the grades divided by the modified Dallas discogram scale, the mechanical stress during extension was greater in grades 3-5 than it was during the others. During extension, the mechanical stress loaded onto the intervertebral disc and endplate was greatest in the posterior portion. Mechanical stresses loaded onto the intervertebral disc were greater in grades 3-5 compared to those in grades 0-2. Our findings suggest that it might be beneficial for patients experiencing discogenic back pain to maintain a neutral posture in their lumbar spine when engaging in daily activities and exercises, especially those suffering from significant intravertebral disc degeneration.

Short-term Hebbian learning can implement transformer-like attention.

Transformers have revolutionized machine learning models of language and vision, but their connection with neuroscience remains tenuous. Built from attention layers, they require a mass comparison of queries and keys that is difficult to perform using traditional neural circuits. Here, we show that neurons can implement attention-like computations using short-term, Hebbian synaptic potentiation. We call our mechanism the match-and-control principle and it proposes that when activity in an axon is synchronous, or matched, with the somatic activity of a neuron that it synapses onto, the synapse can be briefly strongly potentiated, allowing the axon to take over, or control, the activity of the downstream neuron for a short time. In our scheme, the keys and queries are represented as spike trains and comparisons between the two are performed in individual spines allowing for hundreds of key comparisons per query and roughly as many keys and queries as there are neurons in the network.

无症状中国人颈椎Torg-Pavlov比值的分布及意义

无症状中国人颈椎Torg-Pavlov比值的分布及意义

Coordination of hip and spine in individuals with acute low back pain during unstable sitting

BACKGROUND CONTEXTTrunk postural control differs between individuals with and without chronic low back pain. Whether this corresponds to differences in hip/spine coordination during the early acute phase of LBP (ALBP) is unclear. PURPOSETo compare hip/spine coordination in relation to seat movements between individuals with and without ALBP when balancing on an unstable seat and to identify coordination strategies to maintain balance using cluster analysis. STUDY DESIGN/SETTINGCross-sectional observational study. PATIENT SAMPLEALBP (n=130) and pain-free (n=72) individuals. OUTCOME MEASURESFrequency domain measures to evaluate hip/spine coordination (amplitude spectrum, phase angle, coherence) and time-series measures to assess overall balance performance (centre of pressure [CoP] reflecting the amount of seat movements, upper thorax motion as a surrogate for head motion). METHODSParticipants maintained balance while sitting on a seat fixed to a hemisphere. Seat, hip and spine (lower lumbar, lumbar, upper lumbar, thoracic) angular motion and force plate data were recorded. RESULTSOverall, seat/CoP movements (amplitude spectrum and RMSdisplacement) were greater (in both planes) and sagittal coordination (coherence) between the hip or lower spine and seat movements was lower in ALBP than controls. Cluster analysis using coherence data revealed different coordination strategies to maintain balance. Separate clusters used a “lower lumbar strategy” and “hip strategy” in the sagittal plane, and a “lower and upper lumbar strategy” and “lower lumbar strategy” in the frontal plane. A cluster using a “low coherence strategy” in both planes was also identified. CONCLUSIONSHip and lower spine coordination was less in individuals with ALBP in conjunction with a lower quality of overall balance performance. However, interpretation of the relationship between coherence and overall balance performance was not straightforward. Clusters in both the ALBP group and the control group adopted a low coherence strategy, and this was not consistently related to poor overall balance performance. This suggests overall balance performance cannot be inferred from coherence alone and requires consideration of interaction of other different features.

Synaptic plasticity through a naturalistic lens.

From the myriad of studies on neuronal plasticity, investigating its underlying molecular mechanisms up to its behavioral relevance, a very complex landscape has emerged. Recent efforts have been achieved toward more naturalistic investigations as an attempt to better capture the synaptic plasticity underpinning of learning and memory, which has been fostered by the development of in vivo electrophysiological and imaging tools. In this review, we examine these naturalistic investigations, by devoting a first part to synaptic plasticity rules issued from naturalistic in vivo-like activity patterns. We next give an overview of the novel tools, which enable an increased spatio-temporal specificity for detecting and manipulating plasticity expressed at individual spines up to neuronal circuit level during behavior. Finally, we put particular emphasis on works considering brain-body communication loops and macroscale contributors to synaptic plasticity, such as body internal states and brain energy metabolism.

Functional Inhibition of Katanin Affects Synaptic Plasticity.

Dynamic microtubules critically regulate synaptic functions, but the role of microtubule severing in these processes is barely understood. Katanin is a neuronally expressed microtubule-severing complex regulating microtubule number and length in cell division or neurogenesis; however, its potential role in synaptic functions has remained unknown. Studying mice from both sexes, we found that katanin is abundant in neuronal dendrites and can be detected at individual excitatory spine synapses. Overexpression of a dominant-negative ATPase-deficient katanin subunit to functionally inhibit severing alters the growth of microtubules in dendrites, specifically at premature but not mature neuronal stages without affecting spine density. Notably, interference with katanin function prevented structural spine remodeling following single synapse glutamate uncaging and significantly affected the potentiation of AMPA-receptor-mediated excitatory currents after chemical induction of long-term potentiation. Furthermore, katanin inhibition reduced the invasion of microtubules into fully developed spines. Our data demonstrate that katanin-mediated microtubule severing regulates structural and functional plasticity at synaptic sites.

BORS/BJR TRAVELLING FELLOWSHIP: IMAGE-DRIVEN SUBJECT-SPECIFIC SPINE MODELS: DEVELOPING A NOVEL TOOL TO MEASURE IN VIVO LOADING

AbstractObjectivesSpinal disorders such as back pain incur a substantial societal and economic burden. Unfortunately, there is lack of understanding and treatment of these disorders are further impeded by the inability to assess spinal forces in vivo. The aim of this project is to address this challenge by developing and testing a novel image-driven approach that will assess the forces in an individual's spine in vivo by incorporating information acquired from multimodal imaging (magnetic resonance imaging (MRI) and biplane X-rays) in a subject-specific model.MethodsMagnetic resonance and biplane X-ray imaging are used to capture information about the anatomy, tissues, and motion of an individual's spine as they perform a range of everyday activities. This information is then utilised in a subject-specific computational model based on the finite element method to predict the forces in their spine. The project is also utilising novel machine learning algorithms and in vitro, six-axis mechanical testing on human, porcine and bovine samples to develop and test the modelling methods rigorously.Results &amp; DiscussionMRI sequences have been identified that provide high-quality image data and information on different tissue types which will be used to predict subject-specific disc properties. In-vivo protocols to capture motion analysis, EMG muscle activity, and video X-rays of the spine have been designed with planned data collection of 15 healthy volunteers. Preliminary modelling work has evaluated potential machine learning approaches and quantified the sensitivity of the models developed to material properties.ConclusionThe development and testing of these image-driven subject-specific spine models will provide a new tool for determining forces in the spine. It will also provide new tools for measuring and modelling spine movement and quantifying the properties of the spinal tissues.AcknowledgmentsFunding from the EPSRC: EP/V036602/1 (Meakin, Holsgrove &amp; Javadi) and EP/V032275/1 (Holt &amp; Williams).Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Deep Learning-Based Automated Quality Assurance for Palliative Spinal Treatment Planning in Radiotherapy

Robustquality assurance (QA) for palliative spine radiation therapy (RT) remains critical due to the risk of wrong anatomic level treatment on account of human error in enumerating vertebral bodies accurately based on morphology with incomplete imaging of the spine and prevalence of anatomic variants (10%). We propose a rapid, fully automated deep learning-based QA (DL-QA) tool for segmenting and enumerating vertebral structures from image data, capable of identifying misalignment based on discrepancies in calculated dose coverage. Ina retrospective cohort of 514 patients who received palliative spine radiation treatment at a single institution for spinal metastases, vertebral volumes for each individual spine level were automatically segmented on RT planning computed tomography scans using a publicly available deep learning algorithm, Total Segmentator (TS) deployed in the treatment planning system (Wasserthal et al, 2022). Departmental policy requires that the prescription/plan name include all spinal levels that receive a prescribed dosimetric threshold of V50% > 50%. By comparing the intended spine level target in the prescription and plan name against the TS volumes, the DL-QA flagged all cases for which any target vertebrae did not receive this threshold dose and/or any non-targeted vertebrae that received V50% > 50%. To detect spine anomalies, cases were also flagged if any vertebrae volume was not within ±1σ of the entire population of vertebrae volumes. Flagged cases were either categorized as: (1) wrong spine level RT error; (2) documentation error, in which treatment was correct but the prescription/plan name did not follow Departmental policy; or (3) potential spinal geometric error. All flagged cases were verified manually by checking the original images and treatment planning data. Outof 514 patients, 29 cases were flagged as potential errors. Manual review revealed that one of these was a previously discovered true treatment error (due to anatomic variant with 4 lumbar bodies) while 10 were treated as intended but showed documentation errors due to variants in the number of vertebral bodies, kyphosis of the spine causing non-targeted vertebrae to appear in the treatment field, or improper observation of the Departmental plan naming policy. The remaining 18 cases were associated with flagged vertebrae volumes. Reviewing those patients, we identified spinal anomalies where TS attempted to account for extra or missing vertebrae (N = 9) and cases where TS made segmentation errors (N = 9). Theproposed automated DL-QA system successfully identified patients with spine anomalies, flagged documentation errors, verified the correct target levels of spine RT treatments, and detected a known misadministration. The next phase will involve prospective testing of the system in a clinical setting upstream of treatment delivery.

Subcellular Imaging of Neuronal Calcium Handling In Vivo.

Calcium (Ca2+) imaging has been largely used to examine neuronal activity, but it is becoming increasingly clear that subcellular Ca2+ handling is a crucial component of intracellular signaling. The visualization of subcellular Ca2+ dynamics in vivo,where neurons can be studied in their native, intact circuitry, has proven technically challenging in complex nervous systems. The transparency and relatively simple nervous system of the nematode Caenorhabditis elegans enable the cell-specific expression and in vivo visualization of fluorescent tags and indicators. Among these are fluorescent indicators that have been modified for use in the cytoplasm as well as various subcellular compartments, such as the mitochondria. This protocol enables non-ratiometric Ca2+ imaging in vivo with a subcellular resolution that permits the analysis of Ca2+ dynamics down to the level of individual dendritic spines and mitochondria. Here, two available genetically encoded indicators with different Ca2+ affinities are used to demonstrate the use of this protocol for measuring relative Ca2+ levels within the cytoplasm or mitochondrial matrix in a single pair of excitatory interneurons (AVA). Together with the genetic manipulations and longitudinal observations possible in C. elegans, this imaging protocol may be useful for answering questions regarding how Ca2+ handling regulates neuronal function and plasticity.

Microglial motility is modulated by neuronal activity and correlates with dendritic spine plasticity in the hippocampus of awake mice.

Microglia, the resident immune cells of the brain, play a complex role in health and disease. They actively survey the brain parenchyma by physically interacting with other cells and structurally shaping the brain. Yet, the mechanisms underlying microglial motility and significance for synapse stability, especially in the hippocampus during adulthood, remain widely unresolved. Here, we investigated the effect of neuronal activity on microglial motility and the implications for the formation and survival of dendritic spines on hippocampal CA1 neurons in vivo. We used repetitive two-photon in vivo imaging in the hippocampus of awake and anesthetized mice to simultaneously study the motility of microglia and their interaction with dendritic spines. We found that CA3 to CA1 input is sufficient to modulate microglial process motility. Simultaneously, more dendritic spines emerged in mice after awake compared to anesthetized imaging. Interestingly, the rate of microglial contacts with individual dendritic spines and dendrites was associated with the stability, removal, and emergence of dendritic spines. These results suggest that microglia might sense neuronal activity via neurotransmitter release and actively participate in synaptic rewiring of the hippocampal neural network during adulthood. Further, this study has profound relevance for hippocampal learning and memory processes.