The development of the head direction system before eye opening in the rat.

Head direction (HD) cells are neurons found in the hippocampal formation and connected areas that fire as a function of an animal's directional orientation relative to its environment. They integrate self-motion and environmental sensory information to update directional heading. Visual landmarks, in particular, exert strong control over the preferred direction of HD cell firing. The HD signal has previously been shown to appear adult-like as early as postnatal day 16 (P16) in the rat pup, just after eye opening and coinciding with the first spontaneous exploration of its environment. In order to determine whether the HD circuit can begin its organization prior to the onset of patterned vision, we recorded from the anterodorsal thalamic nucleus (ADN) and its postsynaptic target in the hippocampal formation, the dorsal pre-subiculum (PrSd), before and after eye opening in pre-weanling rats. We find that HD cells can be recorded at the earliest age sampled (P12), several days before eye opening. However, this early HD signal displays low directional information content and lacks stability both within and across trials. Following eye opening, the HD system matures rapidly, as more cells exhibit directional firing, and the quality and reliability of the directional signal improves dramatically. Cue-rotation experiments show that a prominent visual landmark is able to control HD responses within 24 hr of eye opening. Together, the results suggest that the directional network can be organized independently of visual spatial information while demonstrating the importance of patterned vision for accurate and reliable orientation in space

Using WhatsApp Focus Group Discussions to Collect Qualitative Data Collection During a Pandemic: Exploring Knowledge, Attitudes, and Perceptions of COVID-19 in Singapore

This qualitative study aimed to explore Singapore residents’ knowledge, attitudes, perceptions, and behaviors around COVID-19 as shaped by different information sources. Through utilizing WhatsApp as a means of conducting digital focus group discussions (FGDs), participants were involved in five consecutive days of discussions through both synchronous and asynchronous means. We found that the use of WhatsApp as a means of conducting FGDs not only served as a means of generating essential, time-sensitive data in the community, but also advanced the quality and quantity of data generated, democratized, and enhanced the participatory nature of FGDs, and facilitated the communication of potential issues around data privacy between facilitators and participants. Although challenges around privacy and confidentiality remain, this means of collecting data is novel in terms of providing timely and relevant data during a pandemic and would be appropriate to be further utilized in the context of other health-related research beyond a public health emergency

The development of spatial and memory circuits in the rat

We provide a concise review of recent studies related to the development of neural circuits supporting spatial navigation and memory in the rat. We chart the relative timeline of the emergence of the four main classes of spatially tuned neurons within the hippocampus and related limbic areas: head direction cells emerge earliest (postnatal day 12, P12), before the eyes of the rats are even open, followed by place cells and boundary responsive cells; grid cells emerge last, around the age of weaning (P21). The rate of maturation is unique to each type of neuron, with the head direction and grid cells showing rapid developmental spurts, in contrast to place cells, which show a more gradual trend of maturation. Interestingly, the emergence of allocentric spatial abilities occurs only after the full complement of spatial neurons becomes functional at P20-21, whereas associative processing in the place cell network is evident from as early as P16. We also present evidence supporting the view that the sensory inputs, which are particularly salient to adult spatial networks, may not be essential for the immature spatial system. Crucially, visual information, although more salient than other sensory modalities for anchoring the adult head direction system, does not appear to be essential for setting up the immature head direction network. We conclude by highlighting an urgent need for new theoretical models that can account for the sequential emergence of spatial cells, as well as the lack of primacy of vision in the early organization of the head direction network. For further resources related to this article, please visit the WIREs website

Effect of intracameral injection of fibrin tissue sealant on the rabbit anterior segment

Molecular Vision161087-1097MVEP

Lower cerebrospinal fluid/plasma fibroblast growth factor 21 (FGF21) ratios and placental FGF21 production in gestational diabetes

Objectives: Circulating Fibroblast Growth Factor 21 (FGF21) levels are increased in insulin resistant states such as obesity, type 2 diabetes mellitus and gestational diabetes mellitus (GDM). In addition, GDM is associated with serious maternal and fetal complications. We sought to study human cerebrospinal fluid (CSF) and corresponding circulating FGF21 levels in women with gestational diabetes mellitus (GDM) and in age and BMI matched control subjects. We also assessed FGF21 secretion from GDM and control human placental explants. Design: CSF and corresponding plasma FGF21 levels of 24 women were measured by ELISA [12 GDM (age: 26–47 years, BMI: 24.3–36.3 kg/m2) and 12 controls (age: 22–40 years, BMI: 30.1–37.0 kg/m2)]. FGF21 levels in conditioned media were secretion from GDM and control human placental explants were also measured by ELISA. Results: Glucose, HOMA-IR and circulating NEFA levels were significantly higher in women with GDM compared to control subjects. Plasma FGF21 levels were significantly higher in women with GDM compared to control subjects [234.3 (150.2–352.7) vs. 115.5 (60.5–188.7) pg/ml; P<0.05]. However, there was no significant difference in CSF FGF21 levels in women with GDM compared to control subjects. Interestingly, CSF/Plasma FGF21 ratio was significantly lower in women with GDM compared to control subjects [0.4 (0.3–0.6) vs. 0.8 (0.5–1.6); P<0.05]. FGF21 secretion into conditioned media was significantly lower in human placental explants from women with GDM compared to control subjects (P<0.05). Conclusions: The central actions of FGF21 in GDM subjects maybe pivotal in the pathogenesis of insulin resistance in GDM subjects. The significance of FGF21 produced by the placenta remains uncharted and maybe crucial in our understanding of the patho-physiology of GDM and its associated maternal and fetal complications. Future research should seek to elucidate these points

The first genome sequences of human bocaviruses from Vietnam.

As part of an ongoing effort to generate complete genome sequences of hand, foot and mouth disease-causing enteroviruses directly from clinical specimens, two complete coding sequences and two partial genomic sequences of human bocavirus 1 (n=3) and 2 (n=1) were co-amplified and sequenced, representing the first genome sequences of human bocaviruses from Vietnam. The sequences may aid future study aiming at understanding the evolution of the pathogen

Ambulatory human motion tracking by fusion of inertial and magnetic sensing with adaptive actuation

Over the last years, inertial sensing has proven to be a suitable ambulatory alternative to traditional human motion tracking based on optical position measurement systems, which are generally restricted to a laboratory environment. Besides many advantages, a major drawback is the inherent drift caused by integration of acceleration and angular velocity to obtain position and orientation. In addition, inertial sensing cannot be used to estimate relative positions and orientations of sensors with respect to each other. In order to overcome these drawbacks, this study presents an Extended Kalman Filter for fusion of inertial and magnetic sensing that is used to estimate relative positions and orientations. In between magnetic updates, change of position and orientation are estimated using inertial sensors. The system decides to perform a magnetic update only if the estimated uncertainty associated with the relative position and orientation exceeds a predefined threshold. The filter is able to provide a stable and accurate estimation of relative position and orientation for several types of movements, as indicated by the average rms error being 0.033 m for the position and 3.6 degrees for the orientation