Hippocampus and retrosplenial cortex combine path integration signals for successful navigation

The current study used fMRI in humans to examine goal-directed navigation in an open field environment. We designed a task that required participants to encode survey-level spatial information and subsequently navigate to a goal location in either first person, third person, or survey perspectives. Critically, no distinguishing landmarks or goal location markers were present in the environment, thereby requiring participants to rely on path integration mechanisms for successful navigation. We focused our analysis on mechanisms related to navigation and mechanisms tracking linear distance to the goal location. Successful navigation required translation of encoded survey-level map information for orientation and implementation of a planned route to the goal. Our results demonstrate that successful first and third person navigation trials recruited the anterior hippocampus more than trials when the goal location was not successfully reached. When examining only successful trials, the retrosplenial and posterior parietal cortices were recruited for goal-directed navigation in both first person and third person perspectives. Unique to first person perspective navigation, the hippocampus was recruited to path integrate self-motion cues with location computations toward the goal location. Last, our results demonstrate that the hippocampus supports goal-directed navigation by actively tracking proximity to the goal throughout navigation. When using path integration mechanisms in first person and third person perspective navigation, the posterior hippocampus was more strongly recruited as participants approach the goal. These findings provide critical insight into the neural mechanisms by which we are able to use map-level representations of our environment to reach our navigational goals

The disease-specific clinical trial network for primary ciliary dyskinesia: PCD-CTN

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by impaired mucociliary clearance leading to irreversible lung damage. In contrast to other rare lung diseases like cystic fibrosis (CF), there are only few clinical trials and limited evidence-based treatments. Management is mainly based on expert opinions and treatment is challenging due to a wide range of clinical manifestations and disease severity. To improve clinical and translational research and facilitate development of new treatments, the clinical trial network for PCD (PCD-CTN) was founded in 2020 under the framework of the European Reference Network (ERN)-LUNG PCD Core. Applications from European PCD sites interested in participating in the PCD-CTN were requested. Inclusion criteria consisted of patient numbers, membership of ERN-LUNG PCD Core, use of associated standards of care, experience in PCD and/or CF clinical research, resources to run clinical trials, good clinical practice (GCP) certifications and institutional support. So far, applications from 22 trial sites in 18 European countries have been approved, including >1400 adult and >1600 paediatric individuals with PCD. The PCD-CTN is headed by a coordinating centre and consists of a steering and executive committee, a data safety monitoring board and committees for protocol review, training and standardisation. A strong association with patient organisations and industrial companies are further cornerstones. All participating trial sites agreed on a code of conduct. As CTNs from other diseases have demonstrated successfully, this newly formed PCD-CTN operates to establish evidence-based treatments for this orphan disease and to bring new personalised treatment approaches to patients

Functional connections between optic flow areas and navigationally responsive brain regions during goal-directed navigation

Recent computational models suggest that visual input from optic flow provides information about egocentric (navigator-centered) motion and influences firing patterns in spatially tuned cells during navigation. Computationally, self-motion cues can be extracted from optic flow during navigation. Despite the importance of optic flow to navigation, a functional link between brain regions sensitive to optic flow and brain regions important for navigation has not been established in either humans or animals. Here, we used a beta-series correlation methodology coupled with two fMRI tasks to establish this functional link during goal-directed navigation in humans. Functionally defined optic flow sensitive cortical areas V3A, V6, and hMT+ were used as seed regions. fMRI data was collected during a navigation task in which participants updated position and orientation based on self-motion cues to successfully navigate to an encoded goal location. The results demonstrate that goal-directed navigation requiring updating of position and orientation in the first person perspective involves a cooperative interaction between optic flow sensitive regions V3A, V6, and hMT+ and the hippocampus, retrosplenial cortex, posterior parietal cortex, and medial prefrontal cortex. These functional connections suggest a dynamic interaction between these systems to support goal-directed navigation

X-ray photoelectron spectroscopy (XPS) and gamma-ray shielding investigation of boro-silicate glasses contained alkali/alkaline modifier

In the present work, seven glass samples have been prepared utilizing melt-quenching method with composition of 40B₂O₃-10SiO₂-10Al₂O₃-30ZnO-10 (Li₂O/Na₂O/K₂O/MgO/CaO/SrO/BaO) all in mol%. Scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDX) have characterized for H3 (K₂O) and H7 (BaO), to examine the structural properties. X-ray Photoelectron Spectroscopy (XPS) has shown that the boron (B) element composition is highest after oxygen elements in all the glasses. It has been also observed that incorporation of potassium (K) and strontium (Sr) elements are maximum compared to the other doped elements into the glass. Further, the photon shielding for H1-H7 samples were also studied. We calculated the mass attenuation coefficients (μ/ρ) for the present samples at some energies between 0.015 and 10 MeV. The results revealed that H7 (BaO) sample owns the highest μ/ρ values followed by H6 (SrO) while H1 (Li₂O) has the lowest μ/ρ. Moreover, H7 and H6 samples have higher effective atomic number than the rest of glasses. H7 sample has excellent shielding properties when compared with the other glasses. We found that the composition of the sample affects the attenuation of the glasses and high attenuation can be achieved when we used heavy metal oxides (such as BaO)