Improving neurodevelopment in Zika-exposed children: A randomized controlled trial

BackgroundWhile microcephaly is a significant adverse outcome of prenatal exposure to the Zika virus (ZIKV), subtle malformations of cortical development (MCD) have been observed in Zika-exposed children (ZEC), including delays in language, cognition, and motor domains, and visual acuity deficits. Interventions within the first 1,000 days of life can significantly improve developmental outcomes. This study examined a 12-week Responsive Caregiving Intervention on neurodevelopmental outcomes in 24-30-month-old ZEC.Methodology/Principal findingsA randomized controlled trial was implemented in Grenada, West Indies using an existing ZIKV cohort surveillance study. When children in that study turned 24 months, baseline child neurodevelopmental measures and caregiver interviews were administered. Caregivers who agreed to participate in the 12-week Responsive Caregiving Intervention, implemented when children were 24–30 months of age, were randomly assigned to the Intervention or Waitlist Control group. Children in both groups were re-assessed on the neurodevelopmental measures post-intervention.Conclusions/Significance233 children from the ZIKV surveillance study met inclusion criteria, of which n = 80 declined participation, n = 42 did not complete the Intervention, and n = 72 missed follow-up assessments given strict timelines in the study design. The final sample for analysis was N = 13 children in the Intervention group and N = 26 children in the Control group. A GEE model analysis showed significantly higher language (p = 0.021) and positive behaviour (p = 0.005) scores for children in the Intervention group compared to the Control group. The Intervention had a medium effect on child language (d = 0.66) and a large effect on positive behaviour (d = 0.83). A 12-week Responsive Caregiving Intervention Programme significantly improves language and positive behaviour scores in 30-month-old normocephalic children who were exposed to ZIKV in utero. The programme provides an option for mothers of ZIKV-exposed children who are seeking an evidence-based neurodevelopmental intervention regardless of known impact of the virus on cortical formation.Trial registrationThe study was registered with clinicaltrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT04697147","term_id":"NCT04697147"}}NCT04697147).     

Oscillatory Activity in the Medial Prefrontal Cortex and Nucleus Accumbens Correlates with Impulsivity and Reward Outcome

Actions expressed prematurely without regard for their consequences are considered impulsive. Such behaviour is governed by a network of brain regions including the prefrontal cortex (PFC) and nucleus accumbens (NAcb) and is prevalent in disorders including attention deficit hyperactivity disorder (ADHD) and drug addiction. However, little is known of the relationship between neural activity in these regions and specific forms of impulsive behaviour. In the present study we investigated local field potential (LFP) oscillations in distinct sub-regions of the PFC and NAcb on a 5-choice serial reaction time task (5-CSRTT), which measures sustained, spatially-divided visual attention and action restraint. The main findings show that power in gamma frequency (50–60 Hz) LFP oscillations transiently increases in the PFC and NAcb during both the anticipation of a cue signalling the spatial location of a nose-poke response and again following correct responses. Gamma oscillations were coupled to low-frequency delta oscillations in both regions; this coupling strengthened specifically when an error response was made. Theta (7–9 Hz) LFP power in the PFC and NAcb increased during the waiting period and was also related to response outcome. Additionally, both gamma and theta power were significantly affected by upcoming premature responses as rats waited for the visual cue to respond. In a subgroup of rats showing persistently high levels of impulsivity we found that impulsivity was associated with increased error signals following a nose-poke response, as well as reduced signals of previous trial outcome during the waiting period. Collectively, these in-vivo neurophysiological findings further implicate the PFC and NAcb in anticipatory impulsive responses and provide evidence that abnormalities in the encoding of rewarding outcomes may underlie trait-like impulsive behaviour.     

Root Starch Reserves Are Necessary for Vigorous Re-Growth following Cutting Back in Lotus japonicus

Perenniality and vegetative re-growth vigour represent key agronomic traits in forage legume (Fabaceae) species. The known determinants of perenniality include the conservation of the vegetative meristem during and after the flowering phase, and the separation of flowering from senescence. The ability of the plants to store nutrient resources in perennial organs and remobilize them may also play an important role in the perennial growth habit, and in determining the capacity of the plant to re-grow following grazing or from one season to the next. To examine the importance of stored starch, we examined the vegetative re-growth vigour following cutting back of a unique collection of Lotus japonicus mutants impaired in their ability to synthesize or degrade starch. Our results establish that starch stored in the roots is important for re-growth vigour in Lotus japonicus. We extended this analysis to a collection of Lotus (trefoil) species and two ecotypes of Lotus japonicus displaying a large variation in their carbohydrate resource allocation. There was a positive correlation between root starch content and re-growth vigour in these natural variants, and a good general correlation between high re-growth vigour and the perennial life-form. We discuss the relationship between perenniality and the availability of root carbohydrates for re-growth.     

Effects of intracoelomic transmitter implantation on metabolic rate,swimming performance,growth and survival in juveniles of two salmonids

In this study, we investigated the effects of acoustic tag implantation on standard and routine metabolic rate (SMR and RMR, estimated via oxygen consumption), critical swimming speed (U_crit), survival and growth in juveniles of rainbow trout Oncorhynchus mykiss and lake trout Salvelinus namaycush. Tag burdens ranged from 1.8% to 7.5% across the two species. Growth rates in acoustic-tagged fish were equal to or higher than those in other treatments. Acoustic-tagged S. namaycush had a marginally lower U_crit than controls but that effect was not replicated in the O. mykiss experiment. Tagging did not have clear effects on metabolic rate but there was an interaction whereby SMR and RMR tended to increase with time since surgery in tagged O. mykiss but not in other treatments (the same trend did not occur in S. namaycush). Survival was high across treatments (mean 98% survival among O. mykiss, 97.5% among S. namaycush). There were no statistically significant effects of tag burden (percentage of body mass) except for a weak negative relationship with growth rate (across species) and a weak positive relationship with U_crit but only in the O. mykiss. Collectively, our findings suggest there were minor, context-dependent effects of acoustic tagging in juvenile S. namaycush and O. mykiss during an eight-week laboratory experiment. Further research will be required to assess whether tagging can cause meaningful behavioural effects in these species in captivity or in the wild and whether there is a tag burden threshold above which deleterious effects consistently occur.     

Passion fruit growing in Kenya

A brief account is given of a minor fruit-growing industry in Kenya. It is an interesting enterprise, because it exemplifies some problems which are apparent in fruit-growing, especially in the tropics, including pest and disease control and commercial outlets. Marketing difficulty is due often to the small quantities involved, which make sales firms reluctant to handle the product not only from the point of view of the initial quantity but also the possibility of repeat orders being unavailable (11).     

Effect of Mesodinium rubrum (= Myrionecta rubra) on the action and absorption spectra of phytoplankton in a coastal marine inlet

This study, carried out at a single station in the Bedford Basin(Nova Scotia, Canada), examined time-dependent changes in thephysical and chemical conditions of the waters with associatedchanges in species composition and some photosynthesis propertiesof phytoplankton. The sampling period covered late summer months(August and September) and fall months (October to December).Changes in the water conditions were found to influence speciescomposition, which in turn had an effect on the shapes and amplitudesof the action and absorption spectra of phytoplankton, and onthe maximum quantum yield of photosynthesis. The most remarkablechange was observed in October during a bloom of Mesodiniumrubrum, a ciliate harbouring photosynthetic endosymbionts richin phycobilins. The presence of M. rubrum yielded atypical shapesof the measured photosynthetic action spectra; furthermore,other photosynthesis properties changed significantly. Theseresults demonstrate that the presence of certain pigments inthe water column may be associated with a marked shift fromwhat may be considered typical (representative) photosynthesisproperties of phytoplankton.