To analyze morphologic and physiological properties of olfactory interneurons in the honeybee, Apis mellifera, antennal lobe (AL) neurons were intracellularly recorded and subsequently labeled with Neurobiotin. Additional focal injections were carried out with cobalt hexamine chloride and dextran fluorescent markers. Olfactory interneurons (projection neurons, PNs) project by means of five tracts, the lateral, the median, and three mediolateral antennocerebral tracts (l-, m-, and ml-ACT, respectively) to the mushroom bodies (MBs) and the protocerebral lobe (PL) of the ipsilateral protocerebrum. Uniglomerular PNs of the m- and l-ACT receiving input from a single glomerulus of the AL also arborize in different regions of the AL. The vast majority of l-ACT innervate the T1 region, whereas m-ACT neurons arborize exclusively in the T2, T3, and T4 regions (T1-4 : AL projection area of sensory cells from the antennae). In the calyces of the MB, uniglomerular PNs form varicosities in the basal ring and the lip region. Individual neurons of both types exhibit unequal innervation within and between the two calyces. In addition, m-ACT fibers ramify more densely within the lip neuropil and show a higher incidence of spine-like processes than l-ACTs. In the PL, l-ACTs arborize exclusively within the lateral horn, whereas some m-ACT neurons innervate a broader region. Multiglomerular neurons of the ml-ACT leave the AL by means of three subtracts (ml-ACT 1-3). Two different types can be distinguished according to their protocerebral target areas: ml-ACTs projecting to the lateral PL (LPL) and to the neuropil around the alpha-lobe (tracts 2 and 3) and neurons projecting only to the LPL (tract 1). Intracellular recordings indicate that both l- and m-ACT neurons respond to general odors but with different response properties, indicating that odor information is processed in parallel pathways with different functional characteristics. Just like m-ACT neurons, ml-ACT neurons respond to odors with complex activity patterns. Bilateral interneurons, originating in the suboesophageal ganglion, connect glomeruli of both AL, and send an axon through the m-ACT in each hemisphere of the brain, terminating in the lip region of the calyces. These neurons respond to contact chemical stimuli.
Neonatal stroke leads to mortality and severe morbidity, but there currently is no effective treatment. Erythropoietin (EPO) promotes cytoprotection and neurogenesis in the short term following brain injury; however, long-term cognitive outcomes and optimal dosing regimens have not been clarified. We performed middle cerebral artery occlusion in postnatal day 10 rats, which were treated with either a single dose of EPO (5 U/g, i.p.) immediately upon reperfusion, or 3 doses of EPO (1 U/g, i.p. each) at 0 h, 24 h, and 7 days after injury. At 3 months after injury, rats treated with 3 doses of EPO did not differ from shams in the Morris water maze, and generally performed better than either rats treated with a single dose or vehicle-treated injured rats. These multiple-dose-treated rats also had increases in hemispheric volume and its subregions. These results suggest that additional, later doses of EPO may be required for cell repair, proliferation, and long-term incorporation into neural networks after neonatal brain injury.
Wnt signaling regulates hippocampal development but little is known about the functions of specific Wnt receptors in this structure. Frizzled 9 is selectively expressed in the hippocampus and is one of about 20 genes typically deleted in Williams syndrome. Since Williams syndrome is associated with severe visuospatial processing defects, we generated a targeted null allele for frizzled 9 to examine its role in hippocampal development. Frizzled 9-null mice had generally normal gross anatomical hippocampal organization but showed large increases in apoptotic cell death in the developing dentate gyrus. This increase in programmed cell death commenced with the onset of dentate gyrus development and persisted into the first postnatal week of life. There was also a perhaps compensatory increase in the number of dividing precursors in the dentate gyrus, which may have been a compensatory response to the increased cell death. These changes in the mutants resulted in a moderate decrease in the number of adult dentate granule cells in null mice and an increase in the number of hilar mossy cells. Heterozygous mice (the same frizzled 9 genotype as Williams syndrome patients) were intermediate between wild type and null mice for all developmental neuronanatomic defects. All mice with a mutant allele had diminished seizure thresholds, and frizzled 9 null mice had severe deficits on tests of visuospatial learning/memory. We conclude that frizzled 9 is a critical determinant of hippocampal development and is very likely to be a contributing factor to the neurodevelopmental and behavioral phenotype of patients with Williams syndrome.
Given the high prevalence of developmental delay in this population, identifying modifiable factors to maximize developmental progress is essential. The home environment would be a targeted method for intervention. Future research is needed to identify the benefits of home-based intervention for this population.
Background Young children with sickle cell disease (SCD) are at risk for cognitive delay. In addition to biologic risk factors associated with SCD, environmental factors contribute to cognitive dysfunction within this cohort. Methods We completed a single arm, prospective cohort study. Children with SCD between the ages of 3–36 months and their caregivers were followed between October 2010 and December 2013. The aim was to describe the role of a home visitation model, the home environment, and socioeconomic status in the development of young children with SCD. Primary outcome measures were the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) and the Home Observation for Measurement of the Environment (HOME). We hypothesized that the home visitation model, Parents as Teachers® (PAT), would encourage positive parent-child interactions and improve cognitive outcomes. Results Thirty-five participants had at least two PAT visits and BSID-III assessments. Mean scores within all five subtests of the BSID-III improved between enrollment and exit, with significant changes within cognitive (p = 0.016) and expressive language domains (p = 0.002). Multivariate modeling found the HOME score associated with the exit results of the cognitive domain. Conclusion We report longitudinal results of the first home visitation program within the early childhood SCD population and show significant improvement in cognitive and expressive language development. Additionally, home environment was a significant predictor of cognitive development. Randomized controlled trials to test the impact of interventions targeting the home environment are warranted for this vulnerable population.
Two distinct neuronal pathways connect the first olfactory neuropil, the antennal lobe, with higher integration areas, such as the mushroom bodies, via antennal lobe projection neurons. Intracellular recordings were used to address the question whether neuroanatomical features affect odor-coding properties. We found that neurons in the median antennocerebral tract code odors by latency differences or specific inhibitory phases in combination with excitatory phases, have a more specific activity profile for different odors and convey the information with a delay. The neurons of the lateral antennocerebral tract code odors by spike rate differences, have a broader activity profile for different odors, and convey the information quickly. Thus, rather preliminary information about the olfactory stimulus first reaches the mushroom bodies and the lateral horn via neurons of the lateral antennocerebral tract and subsequently odor information becomes more specified by activities of neurons of the median antennocerebral tract. We conclude that this neuroanatomical feature is not related to the distinction between different odors, but rather reflects a dual coding of the same odor stimuli by two different neuronal strategies focusing different properties of the same stimulus.
Background The transition from the pediatric setting to adult care is a well‐described period of morbidity and mortality for persons with sickle cell disease (SCD). We sought to measure the feasibility and effectiveness of providing skill‐based educational handouts on improving self‐management and transition readiness in adolescents with SCD. Methods This was a single‐center study in which participants completed a self‐assessment, the Adolescent Autonomy Checklist (AAC), to assess transition readiness and self‐management skills at baseline. After results were reviewed by the study coordinator, participants were provided with skill‐based handouts on noted areas of deficit. The AAC was subsequently completed at a follow‐up visit. All data were stored electronically and transferred into SAS for statistical analyses. Results Sixty‐one patients completed the AAC at baseline and postintervention. At baseline, patients reported needing the most help with skills in money management, living arrangements, vocational skills, and emergency and healthcare skills. Postintervention, statistically significant improvements (P < 0.05) occurred in skills related to laundry, housekeeping, healthcare, and sexual development. A regression model exploring the time to follow‐up showed that most improvements could not be attributed to maturation alone. Conclusion This study showed that educational handouts are a readily implementable and well‐accepted intervention among adolescents with SCD who identify challenges with skills necessary to successfully transition to adult care. Distinguishing which transition needs are best improved with this type of intervention will help to strengthen the multidisciplinary approach necessary to support adolescents and young adults with SCD as they matriculate to adult care.
Plasma catecholamines in newborn rats (0-2 hr old) were analyzed following vaginal birth, cesarean section with simulated labor contractions, or cesarean section without labor contractions. Upon delivery, pups were exposed to key elements of the rat's natural birth process, that is, umbilical cord occlusion, tactile stimulation, and cooling. Only pups exposed to actual or simulated labor showed an immediate rise in norepinephrine and epinephrine. Initial postpartum respiratory frequencies were higher in vaginal than in cesarean delivered pups and, in all groups, inversely correlated with catecholamine titers, suggesting respiratory distress or transient tachypnea at lower catecholamine levels. These findings establish a rat model for analyzing effects of labor on neonatal adaptive response during the transition from prenatal to postnatal life. Keywords fetus; birth; respiration; norepinephrine; epinephrineThe metamorphosis from fetus to newborn constitutes the most profound developmental transformation in a mammal's life. Prior to birth, the mother contributes important resources (e.g., oxygen and glucose) that help maintain and regulate the fetus's physiological systems. During birth, placental connections to the mother are abruptly severed, thereby eliminating this major prenatal support system. To ensure its survival at birth, the newborn mammal must swiftly recruit a veritable constellation of novel physiological and behavioral responses. The onset of pulmonary respiration, reorganization of the heart and circulation, utilization of stored glycogen, and shift to acquiring sustenance from a maternal nipple constitute some of these vital postpartum adaptations.
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