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Childhood critical periods of experience-dependent plasticity are essential for the development of environmentally appropriate behavior and cognition. Disruption of critical periods can alter development of normal function and confer risk for neurodevelopmental disorders. While genes and their expression relevant to neurodevelopment are associated with schizophrenia, the molecular relationship between schizophrenia and critical periods has not been assessed systematically. Here, we apply a transcriptome-based bioinformatics approach to assess whether genes associated with the human critical period for visual cortex plasticity, a well-studied model of cortical critical periods, are aberrantly expressed in schizophrenia and bipolar disorder. Across two dozen datasets encompassing 522 cases and 374 controls, we find that the majority show aberrations in expression of genes associated with the critical period. We observed both hyper- and hypo-critical period plasticity phenotypes at the transcriptome level, which partially mapped to drug candidates that reverse the disorder signatures in silico. Our findings indicate plasticity aberrations in schizophrenia and their treatment may need to be considered in the context of subpopulations with elevated and others reduced plasticity. Future work should leverage ongoing consortia RNA-sequencing efforts to tease out the sources of plasticity-related transcriptional aberrations seen in schizophrenia, including true biological heterogeneity, interaction between normal development/aging and the disorder, and medication history. Our study also urges innovation towards direct assessment of visual cortex plasticity in humans with schizophrenia to precisely deconstruct the role of plasticity in this disorder.

Given that thousands of chemicals released into the environment have the potential capacity to harm neurodevelopment, there is an urgent need to systematically evaluate their toxicity. Neurodevelopment is marked by critical periods of plasticity wherein neural circuits are refined by the environment to optimize behavior and function. If chemicals perturb these critical periods, neurodevelopment can be permanently altered. Focusing on 214 human neurotoxicants, we applied an integrative bioinformatics approach using publically available data to identify dozens of neurotoxicant signatures that disrupt a transcriptional signature of a critical period for brain plasticity. This identified lead (Pb) as a critical period neurotoxicant and we confirmed in vivo that Pb partially suppresses critical period plasticity at a time point analogous to exposure associated with autism. This work demonstrates the utility of a novel informatics approach to systematically identify neurotoxicants that disrupt childhood neurodevelopment and can be extended to assess other environmental chemicals.

High and increasing prevalence of neurodevelopmental disorders place enormous personal and economic burdens on society. Given the growing realization that the roots of neurodevelopmental disorders often lie in early childhood, there is an urgent need to identify childhood risk factors. Neurodevelopment is marked by periods of heightened experience-dependent neuroplasticity wherein neural circuitry is optimized by the environment. If these critical periods are disrupted, development of normal brain function can be permanently altered, leading to neurodevelopmental disorders. Here, we aim to systematically identify human variants in neuroplasticity-related genes that confer risk for neurodevelopmental disorders. Historically, this knowledge has been limited by a lack of techniques to identify genes related to neurodevelopmental plasticity in a high-throughput manner and a lack of methods to systematically identify mutations in these genes that confer risk for neurodevelopmental disorders. Using an integrative genomics approach, we determined loss-of-function (LOF) variants in putative plasticity genes, identified from transcriptional profiles of brain from mice with elevated plasticity, that were associated with neurodevelopmental disorders. From five shared differentially expressed genes found in two mouse models of juvenile-like elevated plasticity (juvenile wild-type or adult Lynx1−/− relative to adult wild-type) that were also genotyped in the Mount Sinai BioMe Biobank we identified multiple associations between LOF genes and increased risk for neurodevelopmental disorders across 10,510 patients linked to the Mount Sinai Electronic Medical Records (EMR), including epilepsy and schizophrenia. This work demonstrates a novel approach to identify neurodevelopmental risk genes and points toward a promising avenue to discover new drug targets to address the unmet therapeutic needs of neurodevelopmental disease.

High and increasing prevalence of neurodevelopmental disorders place enormous personal and economic burdens on society. Given the growing realization that the roots of neurodevelopmental disorders often lie in early childhood, there is an urgent need to identify childhood risk factors. Neurodevelopment is marked by periods of heightened experience-dependent neuroplasticity wherein neural circuitry is optimized by the environment. If these critical periods are disrupted, development of normal brain function can be permanently altered, leading to neurodevelopmental disorders. Here, we aim to systematically identify human variants in neuroplasticity-related genes that confer risk for neurodevelopmental disorders. Historically, this knowledge has been limited by a lack of techniques to identify genes related to neurodevelopmental plasticity in a high-throughput manner and a lack of methods to systematically identify mutations in these genes that confer risk for neurodevelopmental disorders. Using an integrative genomics approach, we determined loss-of-function (LOF) variants in putative plasticity genes, identified from transcriptional profiles of brain from mice with elevated plasticity, that were associated with neurodevelopmental disorders. From five shared differentially expressed genes found in two mouse models of juvenile-like elevated plasticity (juvenile wild-type or adult Lynx1-/- relative to adult wild-type) that were also genotyped in the Mount Sinai BioMe Biobank we identified multiple associations between LOF genes and increased risk for neurodevelopmental disorders across 10,510 patients linked to the Mount Sinai Electronic Medical Records (EMR), including epilepsy and schizophrenia. This work demonstrates a novel approach to identify neurodevelopmental risk genes and points toward a promising avenue to discover new drug targets to address the unmet therapeutic needs of neurodevelopmental disease.

Heightened juvenile cortical plasticity declines into adulthood, posing a challenge for functional recovery following brain injury or disease. A network of inhibition is critical for regulating plasticity in adulthood, yet contributions of interneuron types other than parvalbumin (PV) interneurons have been underexplored. Here we show Lypd6, an endogenous positive modulator of nicotinic acetylcholine receptors (nAChRs), as a specific molecular target in somatostatin (SST) interneurons for reactivating cortical plasticity in adulthood. Selective overexpression of Lypd6 in adult SST interneurons reactivates plasticity through the α2 subtype of nAChR by rapidly activating SST interneurons and in turn inhibiting sub-population of PV interneurons, a key early trigger of the juvenile form of plasticity. Chemogenetic activation of SST interneurons confirms the causal role of SST interneuron activity in reactivating plasticity. Collectively, we identify the Lypd6-nAChRα2 system and associated SST-PV disinhibitory microcircuit as the novel SST interneuron-specific targets for reactivating plasticity in adulthood. This provides potential insights into therapeutic strategies against disorders where recovery is limited due to diminished plasticity in adulthood, such as amblyopia and psychiatric disorders characterized by deficits in SST interneurons.

Postsynaptic remodeling of glutamatergic synapses on ventral striatum (vSTR) medium spiny neurons (MSNs) is critical for shaping stress responses. However, it is unclear which presynaptic inputs are involved. Susceptible mice exhibited increased synaptic strength at intralaminar thalamus (ILT), but not prefrontal cortex (PFC), inputs to vSTR MSNs following chronic social stress. Modulation of ILT-vSTR versus PFC-vSTR neuronal activity differentially regulated dendritic spine plasticity and social avoidance.

Visual Abstract, Throughout childhood and adolescence, periods of heightened neuroplasticity are critical for the development of healthy brain function and behavior. Given the high prevalence of neurodevelopmental disorders, such as autism, identifying disruptors of developmental plasticity represents an essential step for developing strategies for prevention and intervention. Applying a novel computational approach that systematically assessed connections between 436 transcriptional signatures of disease and multiple signatures of neuroplasticity, we identified inflammation as a common pathological process central to a diverse set of diseases predicted to dysregulate plasticity signatures. We tested the hypothesis that inflammation disrupts developmental cortical plasticity in vivo using the mouse ocular dominance model of experience-dependent plasticity in primary visual cortex. We found that the administration of systemic lipopolysaccharide suppressed plasticity during juvenile critical period with accompanying transcriptional changes in a particular set of molecular regulators within primary visual cortex. These findings suggest that inflammation may have unrecognized adverse consequences on the postnatal developmental trajectory and indicate that treating inflammation may reduce the burden of neurodevelopmental disorders.

The spinal nucleus of the bulbocavernosus (SNB) in rodents is a neuromuscular system consisting of lumbar motoneurons and the perineal muscles they innervate, the bulbocavernosus and levator ani. This system is present prenatally in both males and females but degenerates postnatally in females because of the lack of perinatal androgens. Whether androgens act on the motoneurons or muscles in the SNB system to promote survival is a longstanding question. Evidence in rats suggests androgens act primarily on the muscles in development, given that the muscles express androgen receptor (AR) before the critical period of androgen-dependent cell rescue, whereas motoneurons develop AR after this period. We now report, based on a novel AR-reporter mouse model, that AR is expressed in the bulbocavernosus muscles of C57/BL6(J) mice as early as embryonic day 15, while, based on AR-immunocytochemistry, SNB motoneurons do not express AR until postnatal day 4. These results indicate that the ontogeny of AR expression in the mouse SNB system resembles that found in rats, suggesting that androgens may also act on perineal muscles in mice to rescue the SNB system.

Objective: To evaluate the safety, tolerability, and efficacy of glatiramer acetate (GA) 40mg compared to a 20mg dose. Methods: Patients with multiple sclerosis (MS) with ≥1 documented relapse in 12 months prior to screening, or ≥2 documented relapses in 24 months prior to screening, and Expanded Disability Status Scale (EDSS) score 0 to 5.5 were enrolled. Patients were evaluated at screening, baseline, and at months 1, 2, 3, 6, 9, and 12. Primary endpoint was rate of confirmed relapses observed during 12-month study. Analysis was by intent-to-treat. Results: A total of 1,155 patients randomized to GA 20mg (n = 586) or 40mg (n = 569). The groups were well-matched at baseline on demographic, clinical, and magnetic resonance imaging (MRI) characteristics. The primary endpoint was similar in both groups (relative risk [RR] = 1.07; 95% confidence interval [CI], 0.88–1.31; p = 0.486) with mean annualized relapse rates (ARRs) of 0.33 for the 20mg group, 0.35 for the 40mg group, and 0.27 for patients from both groups who completed the entire 1-year treatment. A total of 77% of patients remained relapse-free in both groups. Both groups showed a reduction in mean number of gadolinium-enhancing and new T2 lesions over time with trend for faster reduction in the first trimester with the 40mg dose compared with 20mg dose. Both doses were well-tolerated with a safety profile similar to that observed in previous studies of 20mg GA. Interpretation: In relapsing-remitting MS patients, both the currently-approved GA 20mg and 40mg doses were safe and well-tolerated, with no gain in efficacy for the higher dose. Ann Neurol 2011;69:75–82.

Background: Low adherence to treatment in Multiple Sclerosis (MS) has been shown to lead to poor health outcomes. Various strategies to improve adherence have been suggested including educative programs, injection devices and dedicated nurse assistance. Objective: To assess the impact of elements of the patient support program on adherence; to explore disease factors affecting adherence; and to determine whether these factors influence the choices of supportive elements. Methods: A prospective, observational cohort study was conducted. MS patients were eligible if they had switched to Interferon beta-1b (IFNB-1b) between 1 and 3 months prior to inclusion. Data were collected at months 6, 12, 18 and 24 after inclusion. Adherence was defined as completion of both study protocol and medication at 24 months. Patients underwent evaluations of disability, quality of life, depression, and coping styles. Results: A total of 1077 patients from 15 countries were included, of which 61.8% were adherent to IFNB-1b after 24-months. Depression, quality of life and autoinjector devices were baseline predictors of adherence at 24-months. Coping styles did not show to have substantial impact on adherence. Lower quality of life increased the probability of choosing supportive elements. Conclusion: The study showed that the usage of autoinjector devices chosen during the study was the strongest predictor of drug adherence of all the supportive elements tested in this study. (C) 2011 Elsevier B.V. All rights reserved.

BACKGROUND: The aim of the Betaferon Efficacy Yielding Outcomes of a New Dose (BEYOND) trial was to compare the efficacy, safety, and tolerability of 250 microg or 500 microg interferon beta-1b with glatiramer acetate for treating relapsing-remitting multiple sclerosis. METHODS: Between November, 2003, and June, 2005, 2447 patients with relapsing-remitting multiple sclerosis were screened and 2244 patients were enrolled in this prospective, multicentre, randomised trial. Patients were randomly assigned 2:2:1 by block randomisation with regional stratification to receive one of two doses of interferon beta-1b (250 microg or 500 microg) subcutaneously every other day or 20 mg glatiramer acetate subcutaneously every day. The primary outcome was relapse risk, defined as new or recurrent neurological symptoms separated by at least 30 days from the preceding event and that lasted at least 24 h. Secondary outcomes were progression on the expanded disability status scale (EDSS) and change in T1-hypointense lesion volume. Clinical outcomes were assessed quarterly for 2.0-3.5 years; MRI was done at screening and annually thereafter. Analysis was by per protocol. This study is registered, number NCT00099502. FINDINGS: We found no differences in relapse risk, EDSS progression, T1-hypointense lesion volume, or normalised brain volume among treatment groups. Flu-like symptoms were more common in patients treated with interferon beta-1b (p