Adult neurogenesis involves the generation of new neurons, particularly in the dentate gyrus of the hippocampus. Decreased hippocampal neurogenesis has been implicated in both animal models of depression and in patients with major depressive disorder (MDD), despite some inconsistency in the literature. Here, we build upon current models to generate a new testable hypothesis, linking impaired neurogenesis to downstream psychological outcomes commonly observed in MDD. We contend that disruption in adult neurogenesis impairs pattern separation, a hippocampus-dependent function requiring the careful discrimination and storage of highly similar, but not identical, sensory inputs. This, in turn, can affect downstream processing and response selection, of relevance to emotional wellbeing. Specifically, disrupted pattern separation leads to misperceived stimuli (i.e., stimulus confusion), triggering the selection and deployment of established responses inappropriate for the actual stimuli. We speculate that this may be akin to activation of automatic thoughts, described in the Cognitive Behavior Theory of MDD. Similarly, this impaired ability to discriminate information at a fundamental sensory processing level (e.g., impaired pattern separation) could underlie impaired psychological flexibility, a core component of Acceptance and Commitment Therapy of MDD. We propose that research is needed to test this model by examining the relationship between cognitive functioning (e.g., pattern separation ability), psychological processes (e.g., perseveration and psychological inflexibility), and neurogenesis, taking advantage of emerging magnetic resonance spectroscopy-based imaging that measures neurogenesis in-vivo.

OBJECTIVEThe recognition that neurosurgeons harbor great potential to advocate for the care of individuals with neural tube defects (NTDs) globally has sounded as a clear call to action; however, neurosurgical care and training in low- and middle-income countries (LMICs) present unique challenges that must be considered. The objective of this study was to systematically review publications that describe the challenges and benefits of participating in neurosurgery-related training programs in LMICs in the service of individuals with NTDs.METHODSUsing MEDLINE (PubMed), the authors conducted a systematic review of English- and Spanish-language articles published from 1974 to 2019 that describe the experiences of in-country neurosurgery-related training programs in LMICs. The inclusion criteria were as follows—1) population/exposure: US residents, US neurosurgeons, and local in-country medical staff participating in neurosurgical training programs aimed at improving healthcare for individuals with NTDs; 2) comparison: qualitative studies; and 3) outcome: description of the challenges and benefits of neurosurgical training programs. Articles meeting these criteria were assessed within a global health education conceptual framework.RESULTSNine articles met the inclusion criteria, with the majority of the in-country neurosurgical training programs being seen in subregions of Africa (8/9 [89%]) and one in South/Central America. US-based residents and neurosurgeons who participated in global health neurosurgical training had increased exposure to rare diseases not common in the US, were given the opportunity to work with a collaborative team to educate local healthcare professionals, and had increased exposure to neurosurgical procedures involved in treating NTDs. US neurosurgeons agreed that participating in international training improved their own clinical practices but also recognized that identifying international partners, travel expenses, and interference with their current practice are major barriers to participating in global health education. In contrast, the local medical personnel learned surgical techniques from visiting neurosurgeons, had increased exposure to intraoperative decision-making, and were given guidance to improve postoperative care. The most significant challenges identified were difficulties in local long-term retention of trained fellows and staff, deficient infrastructure, and lower compensation offered for pediatric neurosurgery in comparison to adult care.CONCLUSIONSThe challenges and benefits of international neurosurgical training programs need to be considered to effectively promote the development of neurosurgical care for individuals with NTDs in LMICs. In this global health paradigm, future work needs to investigate further the in-country professionals’ perspective, as well as the related outcomes.

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Background The effect of chemotherapy on brain development in long-term survivors of pediatric acute lymphoblastic leukemia (ALL) was systematically reviewed. Methods A systematic search of Pubmed, Scopus, and PsycINFO databases was conducted to identify articles published between January 2000 and February 2020 that implemented magnetic resonance imaging to assess brain structure and function in pediatric ALL survivors (diagnosed < 21 years of age). The review included articles that were published on children diagnosed with ALL between 0–21 years of age and treated with chemotherapy-only protocols. Articles meeting the inclusion criteria described survivors on average ≥ 5 years from diagnosis, were peer-reviewed articles, and original studies. Results The search yielded 1,975 articles with 23 articles meeting inclusion criteria. The review revealed that survivors had statistically significant alterations in brain anatomy, most commonly a smaller hippocampus and impaired microstructural white matter integrity in frontal brain regions. Survivors also had impaired brain function including lower brain network efficiency and altered resting state connectivity. Survivors also displayed wide-spread reductions in brain activation (ie, frontal, temporal, parietal brain regions) during cognitive tasks. Conclusion While the neurotoxic effects of cancer treatment are reduced in the absence of cranial radiation, survivors treated on chemotherapy-only protocols still display long-term alterations in brain structure and function which contribute to life-long neurocognitive late-effects.

PURPOSE: Aware of the higher birth prevalence of spina bifida (SB) among Hispanics/Latinos, we aimed to appraise the literature as it relates to cultural context through a review of quality of life (QOL) studies conducted among individuals with SB in order to improve care among immigrant families. METHODS: A systematic review was conducted consistent with the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines. The inclusion criteria were: (1) children and adolescents (5-21 years of age) with SB and/or myelomeningocele; (2) quantitative studies; (3) health-related QOL outcome measured by validated instrument determinants; and (4) US-based studies. Articles meeting inclusion criteria were assessed using the focused conceptual framework informing the study (i.e., social determinants of health). RESULTS: Eighteen studies met inclusion criteria, with eight different QOL instruments represented. The majority of studies used generic assessments of QOL (72%), two reported the use of both a generic and a SB-specific QOL measure (11%), and three (17%) documented QOL utilizing a SB-specific validated instrument. Only seven (39%) of the studies stated that they included Hispanics/Latinos and only six (33%) reported including Spanish-speaking individuals. CONCLUSIONS: QOL in individuals with SB is mediated by a wide-range of interrelated factors. In order to better serve this vulnerable population as they transition across the lifespan, multilingual condition-specific QOL measures need to be further developed and implemented among Hispanic/Latino individuals with SB, especially those who are recent immigrants.

An estimated 60% of the world's population lives in Asia, where the incidence of neural tube defects is high. Aware that tethered cord syndrome (TCS) is an important comorbidity, the purpose of this systematic review was to explore the treatment of TCS among individuals living with spina bifida (SB) in Asia. MEDLINE and Embase databases were searched for relevant studies published from January 2000 to June 2018. Search terms such as 'spinal dysraphism,' 'spinabifida,' 'diastematomyelia,' 'lipomeningocele,' 'lypomyelomeningocele,' 'meningomyelocele,' and 'tethered cord syndrome' were used in diverse combinations. Of the 1,290 articles that were identified in accordance with PRISMA (Preferred Items for Systematic Reviews and Meta-Analyses) guidelines, 15 Asia-based studies met the inclusion criteria. Significant differences in the diagnostic criteria and management of TCS were documented. As the surgical techniques for prenatal closure of the spinal defect continue to evolve, their adoption internationally is likely to continue. In this setting, a clear and evidence-based approach to the definition and management of TCS is essential. The recent publication by the Spina Bifida Association of America of their updated care guidelines may serve as a tool used to promote a systematized approach to diagnosing and treating TCS among individuals with SB in the region, as well as globally.

Background Individuals with Down syndrome are predisposed to a number of chronic health conditions, but the relationship between these conditions and cognitive ability is not clear. The primary objective of this systematic review is to assess this relationship by evaluating studies that measure cognitive performance in the context of Down syndrome-associated chronic health conditions. Methods A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Studies included in this review (1) included children, adolescent, and young adult participants with Down syndrome and one or more co-occurring health conditions; (2) were quantitative; and (3) reported outcomes related to both chronic health conditions and cognitive performance. A set of predetermined chronic health conditions that are common in Down syndrome (e.g. sleep disorders, congenital heart disease, thyroid disease, seizure disorders, and pulmonary hypertension) were selected based on prevalence rates in Down syndrome. Results Fifteen studies met inclusion criteria. The majority these of studies assessed cognitive performance in association with sleep disorders (47%) and congenital heart disease (47%). Fewer studies reported on the effect of thyroid disease (7%) and seizure disorders (7%) on

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