Competency-based cardiac imaging for patient-centred care. A statement of the European Society of Cardiology (ESC). With the contribution of the European Association of Cardiovascular Imaging (EACVI), and the support of the Association of Cardiovascular Nursing & Allied Professions (ACNAP), the Association for Acute CardioVascular Care (ACVC), the European Association of Preventive Cardiology (EAPC), the European Association of Percutaneous Cardiovascular Interventions (EAPCI), the European Heart Rhythm Association (EHRA), and the Heart Failure Association (HFA) of the ESC.

Imaging plays an integral role in all aspects of managing heart disease and cardiac imaging is a core competency of cardiologists. The adequate delivery of cardiac imaging services requires expertise in both imaging methodology-with specific adaptations to imaging of the heart-as well as intricate knowledge of heart disease. The European Society of Cardiology (ESC) and the European Association of Cardiovascular Imaging have developed and implemented a successful education and certification programme for all cardiac imaging modalities. This programme equips cardiologists to provide high quality competency-based cardiac imaging services ensuring they are adequately trained and competent in the entire process of cardiac imaging, from the clinical indication via selecting the best imaging test to answer the clinical question, to image acquisition, analysis, interpretation, storage, repository, and results dissemination. This statement emphasizes the need for competency-based cardiac imaging delivery which is key to optimal, effective and efficient, patient care.

Measuring real consumption and consumer price index bias under lockdown conditions.

Millions of goods and services are now unavailable in many countries due to the current coronavirus pandemic, dramatically impacting on the construction of key economic statistics used for informing policy. This situation is unprecedented; hence, methods to address it have not previously been developed. Current advice to national statistical offices from the International Monetary Fund, Eurostat and the United Nations is shown to result in downward bias in the consumer price index (CPI) and upward bias in real consumption. We conclude that, to produce a meaningful CPI within the lockdown period, it is necessary to establish a continuous consumer expenditure survey.

Mesure de la consommation réelle et des biais par défaut de l'indice des prix à la consommation en période de confinement. En raison de la pandémie actuelle de COVID­19, des millions de biens et de services sont présentement indisponibles dans de nombreux pays, entravant significativement l'élaboration de statistiques économiques clés visant à éclairer les politiques. Cette situation est sans précédent, et aucune méthode n'a encore été développée pour y remédier. Les avis dispensés aux organismes nationaux de statistiques par le Fonds monétaire international, Eurostat et les Nations Unies se traduisent par des biais systématiques par défaut quant à l'indice des prix à la consommation (IPC), et par des biais par excès quant à la consommation réelle. Notre conclusion est que pour produire un IPC significatif lors d'un confinement, il est nécessaire de procéder à une enquête continue sur les dépenses de consommation.

Dual-Component Structural Plasticity Mediated by αCaMKII Autophosphorylation on Basal Dendrites of Cortical Layer 2/3 Neurones.

Sensory cortex exhibits receptive field plasticity throughout life in response to changes in sensory experience and offers the experimental possibility of aligning functional changes in receptive field properties with underpinning structural changes in synapses. We looked at the effects on structural plasticity of two different patterns of whisker deprivation in male and female mice: chessboard deprivation, which causes functional plasticity; and all deprived, which does not. Using 2-photon microscopy and chronic imaging through a cranial window over the barrel cortex, we found that layer 2/3 neurones exhibit robust structural plasticity, but only in response to whisker deprivation patterns that cause functional plasticity. Chessboard pattern deprivation caused dual-component plasticity in layer 2/3 by (1) increasing production of new spines that subsequently persisted for weeks and (2) enlarging spine head sizes in the preexisting stable spine population. Structural plasticity occurred on basal dendrites, but not apical dendrites. Both components of plasticity were absent in αCaMKII-T286A mutants that lack LTP and experience-dependent potentiation in barrel cortex, implying that αCaMKII autophosphorylation is not only important for stabilization and enlargement of spines, but also for new spine production. These studies therefore reveal the relationship between spared whisker potentiation in layer 2/3 neurones and the form and mechanisms of structural plasticity processes that underlie them.SIGNIFICANCE STATEMENT This study provides a missing link in a chain of reasoning that connects LTP to experience-dependent functional plasticity in vivo We found that increases in dendritic spine formation and spine enlargement (both of which are characteristic of LTP) only occurred in barrel cortex during sensory deprivation that produced potentiation of sensory responses. Furthermore, the dendritic spine plasticity did not occur during sensory deprivation in mice lacking LTP and experience-dependent potentiation (αCaMKII autophosphorylation mutants). We also found that the dual-component dendritic spine plasticity only occurred on basal dendrites and not on apical dendrites, thereby resolving a paradox in the literature suggesting that layer 2/3 neurones lack structural plasticity in response to sensory deprivation.

Adapting the role of handheld echocardiography during the COVID-19 pandemic: A practical guide.

The COVID-19 pandemic has altered our approach to inpatient echocardiography delivery. There is now a greater focus to address key clinical questions likely to make an immediate impact in management, particularly during the period of widespread infection. Handheld echocardiography (HHE) can be used as a first-line assessment tool, limiting scanning time and exposure to high viral load. This article describes a potential role for HHE during a pandemic. We propose a protocol with a reporting template for a focused core dataset necessary in delivering an acute echocardiography service in the setting of a highly contagious disease, minimising risk to the operator. We cover the scenarios typically encountered in the acute cardiology setting and how an expert trained echocardiography team can identify such pathologies using a limited imaging format and include cardiac presentations encountered in those patients acutely unwell with COVID-19.

Impact of 21-Gene Expression Assay on Clinical Outcomes in Node-Negative ≤ T1b Breast Cancer.

BACKGROUND: Prior to the advent of Oncotype DX 21-gene recurrence score (oDX) assay, the National Comprehensive Cancer Network (NCCN) guideline supported omission of adjuvant chemotherapy in patients with ≤ 1 cm (T1b) hormone receptor-positive (HR +), human epidermal growth factor receptor 2 (HER2-) node tumors. However, around 30% of these patients would have an oDX recurrence score that warrants consideration of adjuvant chemotherapy. To clarify the potential benefit of oDX in these patients, we performed a retrospective analysis comparing clinical outcomes of women with T1a or T1b, N0 HR + HER2- according to performance of oDX. PATIENTS AND METHODS: After receiving institutional review board (IRB) approval, an institutional database was queried to identify patients with HR + HER2- ≤ T1bN0 tumors (n = 2307) diagnosed between 2009 and 2018. Patients were further stratified by recurrence score (RS) defined as low (< 18), intermediate (18-30), or high (> 30). Log-rank, Kaplan-Meier, and inverse probability of treatment weighting (IPW) analyses were used to compare disease-free survival (DFS) and overall survival (OS) across groups. RESULTS: Performance of oDX (n = 1149, 49.8%) was associated with larger tumors, younger age, and White race. On univariate analysis, performance of oDX was associated with improved OS (P < 0.01). On multivariate IPW analysis, performance of oDX lengthened DFS by an average of 16.5 months, while OS was similar between groups (P < 0.01 and P = 0.73). The improved DFS was mainly driven by those with tumors ≥ T1b. CONCLUSIONS: Overall, outcomes were excellent regardless of oDX testing. Performance of oDX testing was associated with improved DFS in patients with tumors ≥ T1b. Our results support routine use of oDX testing in patients with tumors ≥ T1b.

Refining the indications for neoadjuvant chemotherapy for patients with HER2+ breast cancer: A single institution experience.

BACKGROUND: We aim to compare the clinical outcomes of patients with early-stage HER2+ breast cancer treated with adjuvant chemotherapy (AC) and neoadjuvant chemotherapy (NAC). METHODS: Patients with non-metastatic HER2+ breast cancer treated from 2009 to 2018 at our institution comprised our study cohort (n = 1254). Pathologic complete response (pCR) was defined as the absence of invasive disease in the breast and axilla after NAC. Log-rank, Kaplan-Meier, and inverse probability of treatment weighting were used to assess differences in disease-free and overall survival between groups stratified by AC vs. NAC and pCR vs. non-pCR. RESULTS: The majority received AC (n = 787 or 62.8%) while 467 (37.2%) patients received NAC. Median follow up for AC and NAC groups was 46 and 28 months, respectively. The crude disease-free survival and overall survival of our study cohort were 92.2% and 89.1% for AC, 89.1% and 82.2% for NAC pCR, and 68.1% and 60.0% for NAC non-pCR, respectively. For clinical stage ≥IIB patients, NAC conferred a positive but statistically nonsignificant treatment effect over AC in multivariate analysis. CONCLUSIONS: After adjusting for imbalances in our subgroups, we found that, regardless of the sequence of chemotherapy (AC vs. NAC), patients with early-stage HER2+ breast cancer had excellent outcomes.

Oligometastatic Breast Cancer: Is This a Curable Entity? A Contemporary Review of the Literature.

PURPOSE OF REVIEW: Oligometastatic breast cancer (OMBC) remains a poorly understood entity for which no standard of care exists at this time. This review will focus on our biologic understanding of OMBC and provide an update on current treatment strategies. RECENT FINDINGS: The introduction of micro RNA expression profiling has advanced our understanding of the biologic underpinnings of OMBC. Although most of the data regarding treatment have come from retrospective studies, there are now prospective randomized trials reporting progression-free survival and overall survival improvements with stereotactic ablative radiotherapy (SABR). Ongoing studies designed to evaluate addition of SABR as well as other novel agents will further develop this field and provide new treatment options. A "cure" for OMBC remains elusive. With further basic research coupled with novel prospective trials, patients will hopefully enjoy increased progression-free survival and overall survival, and ideally a delay to more toxic systemic therapy.

Production of D-Glyceric acid from D-Galacturonate in Escherichia coli.

A microbial production platform has been developed in Escherichia coli to synthesize D-glyceric acid from D-galacturonate. The expression of uronate dehydrogenase (udh) from Pseudomonas syringae and galactarolactone isomerase (gli) from Agrobacterium fabrum, along with the inactivation of garK, encoding for glycerate kinase, enables D-glyceric acid accumulation by utilizing the endogenous expression of galactarate dehydratase (garD), 5-keto-4-deoxy-D-glucarate aldolase (garL), and 2-hydroxy-3-oxopropionate reductase (garR). Optimization of carbon flux through the elimination of competing metabolic pathways led to the development of a ΔgarKΔhyiΔglxKΔuxaC mutant strain that produced 4.8 g/l of D-glyceric acid from D-galacturonate, with an 83% molar yield. Cultivation in a minimal medium produced similar yields and demonstrated that galactose or glycerol serve as possible carbon co-feeds for industrial production. This novel platform represents an alternative for the production of D-glyceric acid, an industrially relevant chemical, that addresses current challenges in using acetic acid bacteria for its synthesis: increasing yield, enantio-purity and biological stability.

Roadmap for cardiovascular education across the European Society of Cardiology: inspiring better knowledge and skills, now and for the future.

AIMS: The provision of high-quality education allows the European Society of Cardiology (ESC) to achieve its mission of better cardiovascular practice and provides an essential component of translating new evidence to improve outcomes. METHODS AND RESULTS: The 4th ESC Education Conference, held in Sophia Antipolis (December 2016), brought together ESC education leaders, National Directors of Training of 43 ESC countries, and representatives of the ESC Young Community. Integrating national descriptions of education and cardiology training, we discussed innovative pathways to further improve knowledge and skills across different training programmes and health care systems. We developed an ESC roadmap supporting better cardiology training and continued medical education (CME), noting: (i) The ESC provides an excellent framework for unbiased and up-to-date cardiovascular education in close cooperation with its National Societies. (ii) The ESC should support the harmonization of cardiology training, curriculum development, and professional dialogue and mentorship. (iii) ESC congresses are an essential forum to learn and discuss the latest developments in cardiovascular medicine. (iv) The ESC should create a unified, interactive educational platform for cardiology training and continued cardiovascular education combining Webinars, eLearning Courses, Clinical Cases, and other educational programmes, along with ESC Congress content, Practice Guidelines and the next ESC Textbook of Cardiovascular Medicine. (v) ESC-delivered online education should be integrated into National and regional cardiology training and CME programmes. CONCLUSION: These recommendations support the ESC to deliver excellent and comprehensive cardiovascular education for the next generation of specialists. Teamwork between international, national and local partners is essential to achieve this objective.

Hair cell and neural contributions to the cochlear summating potential.

The cochlear summating potential (SP) to a tone is a baseline shift that persists for the duration of the burst. It is often considered the most enigmatic of cochlear potentials because its magnitude and polarity vary across frequency and level and its origins are uncertain. In this study, we used pharmacology to isolate sources of the SP originating from the gerbil cochlea. Animals either had the full complement of outer and inner hair cells (OHCs and IHCs) and an intact auditory nerve or had systemic treatment with furosemide and kanamycin (FK) to remove the outer hair cells. Responses to tone bursts were recorded from the round window before and after the neurotoxin kainic acid (KA) was applied. IHC responses were then isolated from the post-KA responses in FK animals, neural responses were isolated from the subtraction of post-KA from pre-KA responses in NH animals, and OHC responses were isolated by subtraction of post-KA responses in FK animals from post-KA responses in normal hearing (NH) animals. All three sources contributed to the SP; OHCs with a negative polarity and IHCs and the auditory nerve with positive polarity. Thus the recorded SP in NH animals is a sum of contributions from different sources, contributing to the variety of magnitudes and polarities seen across frequency and intensity. When this information was applied to observations of the SP recorded from the round window in human cochlear implant subjects, a strong neural contribution to the SP was confirmed in humans as well as gerbils. NEW & NOTEWORTHY Of the various potentials produced by the cochlea, the summating potential (SP) is typically described as the most enigmatic. Using combinations of ototoxins and neurotoxins, we show contributions to the SP from the auditory nerve and from inner and outer hair cells, which differ in polarity and vary in size across frequency and level. This complexity of sources helps to explain the enigmatic nature of the SP.

Does time to adjuvant chemotherapy (TTC) affect outcomes in patients with triple-negative breast cancer?

PURPOSE: A recent study reported that time to adjuvant chemotherapy (TTC) > 30 days was significantly associated with worse OS and DFS in triple-negative breast cancer (TNBC). Earlier studies, however, found that worse outcomes were associated with TTC > 60 days or > 90 days. As the trend for mastectomy with reconstruction continues to rise, TTC of < 30 days is often not feasible due to wound-healing issues in some of these patients. To elucidate the impact of TTC, we sought to evaluate the clinical outcomes associated with TTC in a contemporary cohort treated for TNBC at a single institution. METHODS: A single-institution database was queried to identify nonmetastatic TNBC patients who received adjuvant chemotherapy from 2009 to 2018. TTC was defined as interval between date of surgery and adjuvant chemotherapy start date. Median TTC was used to divide our cohort into four quartiles; ≤ 31, 32-42, 43-56, and > 56 days. Logrank, Kaplan-Meier, and inverse probability weighting (IPW) tests were used to analyze disease-free (DFS) and overall survival (OS). RESULTS: The mean TTC of our study cohort (n = 724) was 48 days (median TTC = 42 days). Black race, mastectomy without adjuvant radiation, and mastectomy with immediate reconstruction were associated with delayed TTC (all p-values < 0.01). In multivariate IPW analysis, TTC > 56 (n = 173) days did not impact DFS or OS compared to TTC ≤ 31 (n = 198) days (p = 0.27 and p = 0.21, respectively). Similar results were seen during subgroup analysis for groups identified as higher risk for delayed TTC. CONCLUSION: Our results demonstrated that TTC was not significant or significantly associated with DFS or OS in patient receiving chemotherapy for operable TNBC. Our results were reassuring for patients electing mastectomy with immediate reconstruction, who may experience a longer TTC.

Mechanisms underlying the role of DISC1 in synaptic plasticity.

Disrupted in schizophrenia 1 (DISC1) is an important hub protein, forming multimeric complexes by self-association and interacting with a large number of synaptic and cytoskeletal molecules. The synaptic location of DISC1 in the adult brain suggests a role in synaptic plasticity, and indeed, a number of studies have discovered synaptic plasticity impairments in a variety of different DISC1 mutants. This review explores the possibility that DISC1 is an important molecule for organizing proteins involved in synaptic plasticity and examines why mutations in DISC1 impair plasticity. It concentrates on DISC1's role in interacting with synaptic proteins, controlling dendritic structure and cellular trafficking of mRNA, synaptic vesicles and mitochondria. N-terminal directed mutations appear to impair synaptic plasticity through interactions with phosphodiesterase 4B (PDE4B) and hence protein kinase A (PKA)/GluA1 and PKA/cAMP response element-binding protein (CREB) signalling pathways, and affect spine structure through interactions with kalirin 7 (Kal-7) and Rac1. C-terminal directed mutations also impair plasticity possibly through altered interactions with lissencephaly protein 1 (LIS1) and nuclear distribution protein nudE-like 1 (NDEL1), thereby affecting developmental processes such as dendritic structure and spine maturation. Many of the same molecules involved in DISC1's cytoskeletal interactions are also involved in intracellular trafficking, raising the possibility that impairments in intracellular trafficking affect cytoskeletal development and vice versa. While the multiplicity of DISC1 protein interactions makes it difficult to pinpoint a single causal signalling pathway, we suggest that the immediate-term effects of N-terminal influences on GluA1, Rac1 and CREB, coupled with the developmental effects of C-terminal influences on trafficking and the cytoskeleton make up the two main branches of DISC1's effect on synaptic plasticity and dendritic spine stability.

Disparities in Breast Cancer Survival by Socioeconomic Status Despite Medicare and Medicaid Insurance.

Policy Points Patients with low socioeconomic status (SES) experience poorer survival rates after diagnosis of breast cancer, even when enrolled in Medicare and Medicaid. Most of the difference in survival is due to more advanced cancer on presentation and the general poor health of lower SES patients, while only a very small fraction of the SES disparity is due to differences in cancer treatment. Even when comparing only low- versus not-low-SES whites (without confounding by race) the survival disparity between disparate white SES populations is very large and is associated with lower use of preventive care, despite having insurance. CONTEXT: Disparities in breast cancer survival by socioeconomic status (SES) exist despite the "safety net" programs Medicare and Medicaid. What is less clear is the extent to which SES disparities affect various racial and ethnic groups and whether causes differ across populations. METHODS: We conducted a tapered matching study comparing 1,890 low-SES (LSES) non-Hispanic white, 1,824 black, and 723 Hispanic white women to 60,307 not-low-SES (NLSES) non-Hispanic white women, all in Medicare and diagnosed with invasive breast cancer between 1992 and 2010 in 17 US Surveillance, Epidemiology, and End Results (SEER) regions. LSES Medicare patients were Medicaid dual-eligible and resided in neighborhoods with both high poverty and low education. NLSES Medicare patients had none of these factors. MEASUREMENTS: 5-year and median survival. FINDINGS: LSES non-Hispanic white patients were diagnosed with more stage IV disease (6.6% vs 3.6%; p < 0.0001), larger tumors (24.6 mm vs 20.2 mm; p < 0.0001), and more chronic diseases such as diabetes (37.8% vs 19.0%; p < 0.0001) than NLSES non-Hispanic white patients. Disparity in 5-year survival (NLSES - LSES) was 13.7% (p < 0.0001) when matched for age, year, and SEER site (a 42-month difference in median survival). Additionally, matching 55 presentation factors, including stage, reduced the disparity to 4.9% (p = 0.0012), but further matching on treatments yielded little further change in disparity: 4.6% (p = 0.0014). Survival disparities among LSES blacks and Hispanics, also versus NLSES whites, were significantly associated with presentation factors, though black patients also displayed disparities related to initial treatment. Before being diagnosed, all LSES populations used significantly less preventive care services than matched NLSES controls. CONCLUSIONS: In Medicare, SES disparities in breast cancer survival were large (even among non-Hispanic whites) and predominantly related to differences of presentation characteristics at diagnosis rather than differences in treatment. Preventive care was less frequent in LSES patients, which may help explain disparities at presentation.

Whisker row deprivation affects the flow of sensory information through rat barrel cortex.

Whisker trimming causes substantial reorganization of neuronal response properties in barrel cortex. However, little is known about experience-dependent rerouting of sensory processing following sensory deprivation. To address this, we performed in vivo intracellular recordings from layers 2/3 (L2/3), layer 4 (L4), layer 5 regular-spiking (L5RS), and L5 intrinsically bursting (L5IB) neurons and measured their multiwhisker receptive field at the level of spiking activity, membrane potential, and synaptic conductance before and after sensory deprivation. We used Chernoff information to quantify the "sensory information" contained in the firing patterns of cells in response to spared and deprived whisker stimulation. In the control condition, information for flanking-row and same-row whiskers decreased in the order L4, L2/3, L5IB, L5RS. However, after whisker-row deprivation, spared flanking-row whisker information was reordered to L4, L5RS, L5IB, L2/3. Sensory information from the trimmed whiskers was reduced and delayed in L2/3 and L5IB neurons, whereas sensory information from spared whiskers was increased and advanced in L4 and L5RS neurons. Sensory information from spared whiskers was increased in L5IB neurons without a latency change. L5RS cells exhibited the largest changes in sensory information content through an atypical plasticity combining a significant decrease in spontaneous activity and an increase in a short-latency excitatory conductance. NEW & NOTEWORTHY: Sensory cortical plasticity is usually quantified by changes in evoked firing rate. In this study we quantified plasticity by changes in sensory detection performance using Chernoff information and receiver operating characteristic analysis. We found that whisker deprivation causes a change in information flow within the cortical layers and that layer 5 regular-spiking cells, despite showing only a small potentiation of short-latency input, show the greatest increase in information content for the spared input partly by decreasing their spontaneous activity.

Do cortical plasticity mechanisms differ between males and females?

The difference between male and female behavior and male and female susceptibility to a number of neuropsychiatric conditions is not controversial. From a biological perspective, one might expect to see at least some of these differences underpinned by identifiable physical differences in the brain. This Mini-Review focuses on evidence that plasticity mechanisms differ between males and females and ask at what scale of organization the differences might exist, at the systems level, the circuits level, or the synaptic level. Emerging evidence suggests that plasticity differences may extend to the scale of synaptic mechanisms. In particular, the CaMKK, NOS1 and estrogen receptor pathways show sexual dimorphisms with implications for plasticity in the hippocampus and cerebral cortex. © 2016 The Authors. Journal of Neuroscience Research Published by Wiley Periodicals, Inc.

Perceptual learning with tactile stimuli in rodents: Shaping the somatosensory system.

The animal kingdom contains species with a wide variety of sensory systems that have been selected to function in different environmental niches, but that are also subject to modification by experience during an organism's lifetime. The modification of such systems by experience is often called perceptual learning. In rodents, the classic example of perceptual learning is the observation that simple preexposure to two visual stimuli facilitates a subsequent (reinforced) discrimination between them. However, until recently very little behavioral research had investigated perceptual learning with tactile stimuli in rodents, in marked contrast to the wealth of information about plasticity in the rodent somatosensory system. Here we present a selective review of behavioral analyses of perceptual learning with tactile stimuli, alongside evidence concerning the potential bases of such effects within the somatosensory system.

Engineering nonphosphorylative metabolism to synthesize mesaconate from lignocellulosic sugars in Escherichia coli.

Dicarboxylic acids are attractive biosynthetic targets due to their broad applications and their challenging manufacturing process from fossil fuel feedstock. Mesaconate is a branched, unsaturated dicarboxylic acid that can be used as a co-monomer to produce hydrogels and fire-retardant materials. In this study, we engineered nonphosphorylative metabolism to produce mesaconate from d-xylose and l-arabinose. This nonphosphorylative metabolism is orthogonal to the intrinsic pentose metabolism in Escherichia coli and has fewer enzymatic steps and a higher theoretical yield to TCA cycle intermediates than the pentose phosphate pathway. Here mesaconate production was enabled from the d-xylose pathway and the l-arabinose pathway. To enhance the transportation of d-xylose and l-arabinose, pentose transporters were examined. We identified the pentose/proton symporter, AraE, as the most effective transporter for both d-xylose and l-arabinose in mesaconate production process. Further production optimization was achieved by operon screening and metabolic engineering. These efforts led to the engineered strains that produced 12.5g/l and 13.2g/l mesaconate after 48h from 20g/l of d-xylose and l-arabinose, respectively. Finally, the engineered strain overexpressing both l-arabinose and d-xylose operons produced 14.7g/l mesaconate from a 1:1 d-xylose and l-arabinose mixture with a yield of 85% of the theoretical maximum. (0.87g/g). This work demonstrates an effective system that converts pentoses into a value-added chemical, mesaconate, with promising titer, rate, and yield.

Structural plasticity within the barrel cortex during initial phases of whisker-dependent learning.

We report learning-related structural plasticity in layer 1 branches of pyramidal neurons in the barrel cortex, a known site of sensorimotor integration. In mice learning an active, whisker-dependent object localization task, layer 2/3 neurons showed enhanced spine growth during initial skill acquisition that both preceded and predicted expert performance. Preexisting spines were stabilized and new persistent spines were formed. These findings suggest rapid changes in connectivity between motor centers and sensory cortex guide subsequent sensorimotor learning.

Homeostatic plasticity mechanisms are required for juvenile, but not adult, ocular dominance plasticity.

Ocular dominance (OD) plasticity in the visual cortex is a classic model system for understanding developmental plasticity, but the visual cortex also shows plasticity in adulthood. Whether the plasticity mechanisms are similar or different at the two ages is not clear. Several plasticity mechanisms operate during development, including homeostatic plasticity, which acts to maintain the total excitatory drive to a neuron. In agreement with this idea, we found that an often-studied substrain of C57BL/6 mice, C57BL/6JOlaHsd (6JOla), lacks both the homeostatic component of OD plasticity as assessed by intrinsic signal imaging and synaptic scaling of mEPSC amplitudes after a short period of dark exposure during the critical period, whereas another substrain, C57BL/6J (6J), exhibits both plasticity processes. However, in adult mice, OD plasticity was identical in the 6JOla and 6J substrains, suggesting that adult plasticity occurs by a different mechanism. Consistent with this interpretation, adult OD plasticity was normal in TNFα knockout mice, which are known to lack juvenile synaptic scaling and the homeostatic component of OD plasticity, but was absent in adult α-calcium/calmodulin-dependent protein kinase II;T286A (αCaMKII(T286A)) mice, which have a point mutation that prevents autophosphorylation of αCaMKII. We conclude that increased responsiveness to open-eye stimulation after monocular deprivation during the critical period is a homeostatic process that depends mechanistically on synaptic scaling during the critical period, whereas in adult mice it is mediated by a different mechanism that requires αCaMKII autophosphorylation. Thus, our study reveals a transition between homeostatic and long-term potentiation-like plasticity mechanisms with increasing age.