Head Restraint Research Articles

Effects of head restraint (HR) interference on child restraint system (CRS) performance in frontal and far-side impacts.

Forward-facing child restraint systems (FF CRS) and high-back boosters often contact the vehicle seat head restraint (HR) when installed, creating a gap between the back surface of the CRS and the vehicle seat. The effects of HR interference on dynamic CRS performance are not well documented. The objective of this study is to quantify the effects of HR interference for FF CRS and high-back boosters in frontal and far-side impacts. Production vehicle seats with prominent, removeable HRs were attached to a sled buck. One FF CRS and two booster models were tested with the HR in place (causing interference) and with the HR removed (no interference). A variety of installation methods were examined for the FF CRS. A total of twenty-four tests were run. In frontal impacts, HR interference produced small but consistent increases in frontal head excursion and HIC36. Head excursions were more directly related to the more forward initial position rather than kinematic differences caused by HR interference. In far-side impacts, HR interference did not have consistent effects on injury metrics. Overall, these results suggest only slight benefits of removing the HR in frontal impacts specifically. Caregivers should use caution if removing a vehicle HR to ensure that the current child occupant and all future vehicle occupants have adequate head support available in case of a rear impact.

Causes, effects and treatment of forward head posture. Systematic literature review

The human cervical spine, with its complex structure, is designed to serve unique biomechanical functions. In addition to providing support and protection for the skull, the cervical spine also acts as a shock absorber for brain structures. Mechanically, it transfers weight and facilitates head flexion movements. To effectively carry out its function, proper alignment of the head’s posture with the body’s vertical center of gravity is necessary to minimize pressure and tension on spinal muscles. When continuous activities involving head restraint or forward bending cause an anterior translation of the head over extended periods of time, it can lead to a condition known as forward head posture (FHP). Prolonged FHP can result in injuries to muscles, tendons, and ligaments within both the cervical and lumbar regions of the spine, resulting in various health issues such as neck pain, shoulder pain or discomfort in the upper thoracic scapular segment. The aim of this study was to determine the impact, causes, and management strategies that can be implemented when forward posture occurs in individuals. The data used for this research were obtained from accredited journals such as Mendeley and PubMed. Articles were searched based on keywords related to forward head posture and then filtered according to inclusion and exclusion criteria. Ten out of 140 articles were selected as primary sources for this study. The results indicate that one significant impact of forward head posture is acute neck pain, which primarily affects an individual’s balance negatively. Known causes of forward head posture include engaging in work that involves repetitive bending or maintaining a static position where one leans their neck forwards continuously over prolonged periods. Finally, the recommended management approach when dealing with forward head posture is treatment through exercise therapy, such as Chin tuck exercise, McKenzie Neck Exercise, and Forward Head Posture Exercise.

Low-cost, portable, easy-to-use kiosks to facilitate home-cage testing of nonhuman primates during vision-based behavioral tasks.

Nonhuman primates (NHPs), especially rhesus macaques, have significantly contributed to our understanding of the neural computations underlying human vision. Besides the established homologies in the visual brain areas between these species and our ability to probe detailed neural mechanisms in monkeys at multiple scales, NHPs' ability to perform human-like visual behavior makes them an extremely appealing animal model of human vision. Traditionally, such behavioral studies have been conducted in controlled laboratory settings, offering experimenters tight control over variables like luminance, eye movements, and auditory interference. However, in-lab experiments have several constraints, including limited experimental time, the need for dedicated human experimenters, additional lab space requirements, invasive surgeries for headpost implants, and extra time and training for chairing and head restraints. To overcome these limitations, we propose adopting home-cage behavioral training and testing of NHPs, enabling the administration of many vision-based behavioral tasks simultaneously across multiple monkeys with reduced human personnel requirements, no NHP head restraint, and monkeys' unrestricted access to experiments. In this article, we present a portable, low-cost, easy-to-use kiosk system developed to conduct home-cage vision-based behavioral tasks in NHPs. We provide details of its operation and build to enable more open-source development of this technology. Furthermore, we present validation results using behavioral measurements performed in the lab and in NHP home cages, demonstrating the system's reliability and potential to enhance the efficiency and flexibility of NHP behavioral research.NEW & NOTEWORTHY Training nonhuman primates (NHPs) for vision-based behavioral tasks in a laboratory setting is a time-consuming process and comes with many limitations. To overcome these challenges, we have developed an affordable, open-source, wireless, touchscreen training system that can be placed in the NHPs' housing environment. This system enables NHPs to work at their own pace. It provides a platform to implement continuous behavioral training protocols without major experimenter intervention and eliminates the need for other standard practices like NHP chair training, collar placement, and head restraints. Hence, these kiosks ultimately contribute to animal welfare and therefore better-quality neuroscience in the long run. In addition, NHPs quickly learn complex behavioral tasks using this system, making it a promising tool for wireless electrophysiological research in naturalistic, unrestricted environments to probe the relation between brain and behavior.

Comparison of Depth-Related Visuomotor Task Performance in Uniocular Individuals and in Binocular Controls With and Without Temporary Monocular Occlusion.

Do one-eyed (uniocular) humans use monocular depth cues differently from those with intact binocularity to perform depth-related visuomotor tasks that emulate complex activities of daily living? If so, does performance depend on the participant's age, duration of uniocularity and head movements? Forty-five uniocular cases (age range 6-37years; 2.4months-31.0years of uniocularity) and 46 age-similar binocular controls performed a task that required them to pass a hoop around an electrified wire convoluted in depth multiple times, while avoiding contact as indicated by auditory feedback. The task was performed with and without head restraint, in random order. The error rate and speed were calculated from the frequency of contact between the hoop and wire and the total task duration (adjusting for error time), respectively, all determined from video recordings of the task. Head movements were analyzed from the videos using face-tracking software. Error rate decreased with age (P < 0.001) until the late teen years while speed revealed no such trend. Across all ages, the error rate increased and speed decreased in the absence of binocularity (P < 0.001). There was no additional error reduction with duration of uniocularity (P = 0.16). Head movements provided no advantage to task performance, despite generating parallax disparities comparable to binocular viewing. Performance in a dynamic, depth-related visuomotor task is reduced in the absence of binocular viewing, independent of age-related performance level. This study finds no evidence for a prolonged experience with monocular depth cues being advantageous for such tasks over transient loss of binocularity.

Evaluation of a novel head and neck restraint for harness-restrained children

Motor Vehicle Crashes (MVCs) are a common source of neck injury and, although rare, catastrophic neck injury occurs in restrained children up to age 10 years old. Recently, a head/neck support (HNS) that cradles the head during sleep was developed. The objective of this study was to determine if the HNS improves injury criteria measured on anthropomorphic test devices (ATDs) in front facing 5-point harness child restraint systems (FFCRS). Nineteen matched pair frontal impact sled tests were conducted with ATDs representing the 12 month old, or 3 or 6 year old child in FFCRS. HNS reduced HIC36 by median 22.2%, maximum resultant head acceleration (3ms clip) by 16.2%, head excursion by 8.2%, and neck tension by 12.2%. Providing supplemental restraint directly to the head has the potential to improve injury outcomes while not adding to harm during common misuse scenarios, but further research is needed to determine if these benefits persist in real-world crashes.

Design of Driver Seat in Automobile Car

Driver seat in the automobile is an important system. There are so many parts in the driver seat which made it a complicated system. Adjustments as well as safety systems. A seat adjustment includes height adjustment, fore and aft adjustment, back recline adjustments. Safety systems include seat belts, air bags and advanced head restraints. Generally professional driver works more than eight hours per day of a week, therefore driver seat must be designed by considering all the parameters. Also uneven road condition induces the vibration in a vehicle transmitted to driver body. Poorly designed driver seat affects the driver health and psychological conditions of mind. Three main objectives of any driver seats are safety, health and comfort of driver. This paper presents all the parameters of driver seat such as anthropometry of human, ergonomics related parameters, seat materials, safety related parameters, comfort related parameters as well as weight and aesthetics with classifications and basics of driver seat.

Increased freedom of head movement mitigates stress and bacterial load in the airways of horses during transport.

Protection of horse welfare during transport is crucial. The aim of this study was to determine the effect of head and neck restraint on behavior and airway bacteria. In a randomized crossover study, six healthy Thoroughbreds were transported by road for 22 h in an individual bay with tight head restraint (50 cm short-rope) or loose head restraint (95 cm long-rope). Behavioral parameters relating to head position, eating, and stress were monitored during transportation. Tracheal wash samples were obtained 6 days before and immediately after transport for bacterial culture and metagenomic analysis. Compared to before transport, bacterial load (CFU/mL) after transport was significantly increased in the short-rope group (p = 0.04), whereas no changes were observed in the long-rope group. Transport significantly reduced Simpson index at phylum, class, order, and family levels in both groups (p < 0.001) of tracheal microbiota. In both groups, this reduction was associated with increases in the dominant members of relative abundance at phylum (Firmicutes: +24% in long-rope and +14% in short-rope), class (Bacilli: +20% in long-rope and +22% in short-rope) and family (Streptococcaceae: +22% in long-rope and +23% in short-rope) levels. Licking behavior during transportation with short-rope restraint was more frequent than in horses with long-rope restraint. These results suggest loose head restraint during transportation is likely to ameliorate stress and mitigate the associated increased bacterial load in the lower airways associated with transport. Further, head position during transportation is likely a more important determinant of airway hygiene and distress than duration of travel.

Head-centric computing for vestibular stimulation under head-free conditions.

Background: The vestibular end organs (semicircular canals, saccule and utricle) monitor head orientation and motion. Vestibular stimulation by means of controlled translations, rotations or tilts of the head represents a routine manoeuvre to test the vestibular apparatus in a laboratory or clinical setting. In diagnostics, it is used to assess oculomotor postural or perceptual responses, whose abnormalities can reveal subclinical vestibular dysfunctions due to pathology, aging or drugs. Objective: The assessment of the vestibular function requires the alignment of the motion stimuli as close as possible with reference axes of the head, for instance the cardinal axes naso-occipital, interaural, cranio-caudal. This is often achieved by using a head restraint, such as a helmet or strap holding the head tightly in a predefined posture that guarantees the alignment described above. However, such restraints may be quite uncomfortable, especially for elderly or claustrophobic patients. Moreover, it might be desirable to test the vestibular function under the more natural conditions in which the head is free to move, as when subjects are tracking a visual target or they are standing erect on the moving platform. Here, we document algorithms that allow delivering motion stimuli aligned with head-fixed axes under head-free conditions. Methods: We implemented and validated these algorithms using a MOOG-6DOF motion platform in two different conditions. 1) The participant kept the head in a resting, fully unrestrained posture, while inter-aural, naso-occipital or cranio-caudal translations were applied. 2) The participant moved the head continuously while a naso-occipital translation was applied. Head and platform motion were monitored in real-time using Vicon. Results: The results for both conditions showed excellent agreement between the theoretical spatio-temporal profile of the motion stimuli and the corresponding profile of actual motion as measured in real-time. Conclusion: We propose our approach as a safe, non-intrusive method to test the vestibular system under the natural head-free conditions required by the experiential perspective of the patients.

Advances in cellular resolution microscopy for brain imaging in rats.

Rats are used in neuroscience research because of their physiological similarities with humans and accessibility as model organisms, trainability, and behavioral repertoire. In particular, rats perform a wide range of sophisticated social, cognitive, motor, and learning behaviors within the contexts of both naturalistic and laboratory environments. Further progress in neuroscience can be facilitated by using advanced imaging methods to measure the complex neural and physiological processes during behavior in rats. However, compared with the mouse, the rat nervous system offers a set of challenges, such as larger brain size, decreased neuron density, and difficulty with head restraint. Here, we review recent advances in in vivo imaging techniques in rats with a special focus on open-source solutions for calcium imaging. Finally, we provide suggestions for both users and developers of in vivo imaging systems for rats.

An easy-to-implement, non-invasive head restraint method for monkey fMRI

Functional magnetic resonance imaging (fMRI) in behaving monkeys has a strong potential to bridge the gap between human neuroimaging and primate neurophysiology. In monkey fMRI, to restrain head movements, researchers usually surgically implant a plastic head-post on the skull. Although time-proven to be effective, this technique could create burdens for animals, including a risk of infection and discomfort. Furthermore, the presence of extraneous objects on the skull, such as bone screws and dental cement, adversely affects signals near the cortical surface. These side effects are undesirable in terms of both the practical aspect of efficient data collection and the spirit of “refinement” from the 3R's. Here, we demonstrate that a completely non-invasive fMRI scan in awake monkeys is possible by using a plastic head mask made to fit the skull of individual animals. In all of the three monkeys tested, longitudinal, quantitative assessment of head movements showed that the plastic mask has effectively suppressed head movements, and we were able to obtain reliable retinotopic BOLD signals in a standard retinotopic mapping task. The present, easy-to-make plastic mask has a strong potential to simplify fMRI experiments in awake monkeys, while giving data that is as good as or even better quality than that obtained with the conventional head-post method.

A new method for analyzing the thermomechanical behavior and the null point movement of energy piles

During heating or cooling, an energy pile elongates or shortens around the null point, where the thermally induced displacement is zero. Previously proposed computing methods typically require an initial null point assumption and iterations before calculating the thermomechanical response. We proposed a new method to directly calculate the thermomechanical response of energy piles based on the boundary shape function and load transfer approach, and we verified its feasibility by comparing the results with a field test. Then, this work investigated the effects of the pile head and tip restraint conditions, soil restraint, and thermal and initial mechanical load magnitudes on the thermomechanical response of energy piles through a series of case studies, particularly focusing on the interaction between the aforementioned influencing factors and the null point location. The analysis demonstrates that the position of the null point is primarily determined by the end restraint boundary conditions of the pile; however, changing the soil restraint and thermal load will cause the null point to move, and the direction and distance of the movement are related to the symmetry between the two extremity restraint conditions. Finally, changing the initial mechanical load also shifts the null point position.

Optimising the tether angle of a head and neck restraint

This study used models of a helmeted human and Hybrid III anthropomorphic test device (HIII ATD) head and neck to analyse the effects of changing the helmet to device tether angle on a head and neck restraint (HNR). Models were validated against literature before attaching a linear spring tether. Bayesian optimisation determined the optimal design parameters for three different tether setups. The validation results show that the human model may underestimate injury risk, even though it predicts a greater risk than the HIII ATD model. Therefore, the underestimated values of the human model may represent a conservative approach when used for device versus baseline comparative analysis. Conversely, the HIII ATD model underestimates the maximum head displacement. Since head displacement is required for the tethers to reduce injury risk, the human model may yield more beneficial results. Overall, improvements could be made to both models, but it is more important to tailor each model to the specific test environment. It was found that the human model’s optimal tether angle is 8.83 degrees below the horizontal and that there is 13 degrees’ difference between the optimal tether angles of the human and HIII ATD models. Therefore, HNR designs focused on the results from HIII ATD testing may be less effective for humans. Additionally, increasing the height of the tether’s attachment point on the helmet by approximately 35 mm may improve the HNR’s ability to further reduce the injury risk. Future work may include testing oblique impacts or using finite element models.

Soil–Structure Interactions in a Capped CBP Wall System Triggered by Localized Hydrogeological Drawdown in a Complex Geological Setting

Retaining walls are often used to construct basements and underground station boxes. This unique case study compares the field-measured contiguous bored pile (CBP) wall, surrounding geology, and hydrogeology or groundwater responses against the results using 2D and 3D numerical back analyses of a deep excavation project that experienced localized groundwater drawdown through the leaking ground anchor points. Site observations indicated that the ground anchor installation works had caused larger than expected through-the-wall leakages that subsequently triggered nearby ground and building settlements. In order to study the complex soil–structure interaction behavior, back analyses using a hybrid modeling technique of through-the-wall transient hydrogeological seepage and geomaterial stress-strain analyses was implemented. Through these soil-structure interaction back analyses, it was evidently revealed that the presence of the continuous capping beam was key in providing pile head restraints against the active earth pressures when the groundwater was depressed, as well as efficiently distributing the beneficial wall corner effects towards the middle CBP wall, leading to smaller bending moment magnitudes, characterized by their ‘S-shaped’ profiles. This behavior had been correctly diagnosed, as opposed to the ‘D-shaped’ bending moment profile usually only seen in a typical free-head cantilever wall in similar geology. The eventual results show that the wall and ground responses, i.e., deflection, bending moment, and settlement, were reasonably well predicted when compared against the instrumented field data, thus validating the reliability of the geotechnical modeling technique, key geological parameters, and hydrogeological fluctuations adopted in the 2D and 3D numerical models, as well as the beneficial contributions of the continuous capping beam, which tend to be overlooked during routine retaining wall design.

Integrating biomechanics with stakeholder perspectives to inform safety in grassroots dirt track racing

Grassroots dirt track racing is a foundational part of motorsports with a high risk of severe injury. This study aimed to gather perspectives and experiences of motorsports drivers surrounding safety and head acceleration events experienced during grassroots dirt track racing to inform strategies to improve driver safety. Thirteen drivers (n=9 who primarily race on dirt tracks; n=4 who primarily race on pavement tracks) with prior dirt track racing experience participated in separate, group-specific focus groups and/or one-on-one interviews where video, simulations of head motion, and head acceleration data were shared. Peak kinematics of laps and crash contact scenarios were recorded, and head perturbations (i.e., deviations in head motion relative to its moving-average trajectory) were quantified for each lap and presented through guided discussion. Responses were summarized using Rapid Assessment Process. Audio recordings and field notes were collected from focus groups and interviews and analyzed across 25 domains. Drivers described dirt track racing as short, fast bursts of racing. Benefits of dirt track racing for driver development were described, including learning car control. Drivers acknowledged risks of racing and expressed confidence in safety equipment but identified areas for improvement. Drivers observed lateral bouncing of the head in video and simulations but recognized that such motions were not noticed while racing. Track conditions and track type were identified as factors influencing head perturbations. Mean PLA (5.5 g) and PRV (3.07 rad/s) of perturbations experienced during racing laps and perturbation frequencies of 5 and 7 perturbations per second were reported. Generally, drivers accurately estimated the head acceleration magnitudes but were surprised by the frequency and maximum magnitude of perturbations. Maximum perturbation magnitudes (26.8 g and 19.0 rad/s) were attributed to hitting a “rut” in the dirt. Drivers described sudden stops, vertical loads due to landing from a large height, and impacts to the vehicle frame as crash events they physically feel the most. Summary statistics for crashes (medians = 7.30 g, 6.94 rad/s) were reported. Typical impact magnitudes measured in other sports (e.g., football) were provided for context. Upon reviewing the biomechanics, drivers were surprised that crash accelerations were relatively low compared to other contact/collision sports. Pavement drivers noted limited safety features in dirt track racing compared to pavement, including rigidity of vehicle frames, seat structure, seatbelt integration, and lack of oversight from sanctioning bodies. Most drivers felt seat inserts and head and neck restraints are important for injury prevention; however, usage of seat inserts and preferred head and neck restraint system differed among drivers. Drivers described their perspectives and experiences related to safety and identified strategies to improve safety in grassroots dirt track racing. Drivers expressed support for future safety research.

Two-Photon Calcium Imaging of Forebrain Activity in Behaving Adult Zebrafish.

Adult zebrafish (Danio rerio) exhibit a rich repertoire of behaviors for studying cognitive functions. They also have a miniature brain that can be used for measuring activities across brain regions through optical imaging methods. However, reports on the recording of brain activity in behaving adult zebrafish have been scarce. The present study describes procedures to perform two-photon calcium imaging in the dorsal forebrain of adult zebrafish. We focus on steps to restrain adult zebrafish from moving their heads, which provides stability that enables laser scanning imaging of the brain activity. The head-restrained animals can freely move their body parts and breathe without aids. The procedure aims to shorten the time of head restraint surgery, minimize brain motion, and maximize the number of neurons recorded. A setup for presenting an immersive visual environment during calcium imaging is also described here, which can be used to study neural correlates underlying visually triggered behaviors.

Inductively coupled, transmit-receive coils for proton MRI and X-nucleus MRI/MRS in small animals

We report several inductively coupled RF coil designs that are very easy to construct, produce high signal-to-noise ratio (SNR) and high spatial resolution while accommodating life support, anesthesia and monitoring in small animals. Inductively coupled surface coils were designed for hyperpolarized 13 C MR spectroscopic imaging (MRSI) of mouse brain, with emphases on the simplicity of the circuit design, ease of use, whole-brain coverage, and high SNR. The simplest form was a resonant loop designed to crown the mouse head for a snug fit to achieve full coverage of the brain with high sensitivity when inductively coupled to a broadband pick-up coil. Here, we demonstrated the coil's performance in hyperpolarized 13 C MRSI of a normal mouse and a glioblastoma mouse model at 4.7 T. High SNR exceeding 70:1 was obtained in the brain with good spatial resolution (1.53 mm x 1.53 mm). Similar inductively coupled loop for other X-nuclei can be made very easily in a few minutes and achieve high performance, as demonstrated in 31 P spectroscopy. Similar design concept was expanded to splitable, inductively coupled volume coils for high-resolution proton MRI of marmoset at 3T and 9.4T, to easily accommodate head restraint, vital-sign monitoring, and anesthesia delivery.

In Vivo Fiber-Coupled Pre-Clinical Confocal Laser-scanning Endomicroscopy (pCLE) of Hippocampal Capillaries in Awake Mice.

The goal of this protocol is to describe fiber-optic-bundle-coupled pre-clinical confocal laser-scanning endomicroscopy (pCLE) in its specific application to elucidate capillary blood flow effects during seizures, driven by mural cells. In vitro and in vivo cortical imaging have shown that capillary constrictions driven by pericytes can result from functional local neural activity, as well as from drug application, in healthy animals. Here, a protocol is presented on how to use pCLE to determine the role of microvascular dynamics in neural degeneration in epilepsy, at any tissue depth (specifically in the hippocampus). We describe a head restraint technique that has been adapted to record pCLE in awake animals, to address potential side-effects of anesthetics on neural activity. Using these methods, electrophysiological and imaging recordings can be conducted over several hours in deep neural structures of the brain.

A current assessment of the THOR 50M in rear impacts

Objective This study presents a comparison of the Test Device for Human Occupant Restraint (THOR) 50M and Hybrid III (HIII) 50M anthropomorphic test device (ATD) geometries and rear impact head and neck biofidelity to each other and to postmortem human surrogate (PMHS) data to evaluate the usefulness of the THOR in rear impact testing. Methods Both ATDs were scanned in a seated position on a rigid bench seat. A series of rear impact sled tests with the rigid bench seat with no head restraint support were conducted with a HIII-50M at 16 and 24 kph. Tests at each speed were performed twice with the THOR-50M to allow an assessment of the repeatability of the THOR-50M. A comparison of the test results from THOR-50M testing were made to the results of a previous study that included PMHS. Rear impact sled tests with both ATDs in a modern seat were then conducted at 40 kph. Results The THOR-50M head was 48.4 mm rearward and 60.1 mm higher than the HIII-50M head when seated in the rigid bench seat. In the repeated rigid bench testing at 16 and 24 kph, the THOR-50M head longitudinal and vertical accelerations, upper neck moment, and overall kinematics showed good test-to-test repeatability. In the rigid bench tests, the THOR-50M neck experienced flexion prior to extension in the 16 kph tests, where the neck of the HIII only experienced extension. At 24 kph both ATDs only experienced extension. The THOR-50M head displaced more rearward at both test velocities. The rigid bench tests show that the THOR-50M neck allows for more extension motion or articulation than the HIII-50M neck. The rigid bench test also shows that the head longitudinal and vertical accelerations, angular head kinematics, and upper neck moments were reasonably comparable between the ATDs. The THOR-50M results were closer to the average of the PMHS results than the HIII-50-M results, with the exception of the upper neck. In the 40 kph tests, with a modern seat design, the THOR-50M resulted in more deformation of the seatback with greater head restraint loading than the HIII-50M. The THOR-50M head backset distance was less. Conclusion This study provides insight into the differences and similarities between the THOR and the HIII-50M ATD geometries, instrumentation responses, and kinematics, as well as the repeatability of the THOR-50M in rear impacts testing. The overall geometries of the THOR-50M and the HIII-50M are similar. The seated head position of the THOR-50M is slightly further rearward and higher than the HIII-50M. The results indicate that the THOR-50M matches the PMHS results more closely than the HIII-50M and may have improved neck biofidelity in rear impact testing. The results indicate that the studied THOR-50M responses are repeatable within expected test-to-test variations in rear impacts. Early data suggest that the THOR-50M can be used in rear impact testing, though a more complete understanding of the THOR-50M differences to the HIII ATDs will allow for better correlation to the existing body of HIII rear impact testing.

A cranial implant for stabilizing whole-cell patch-clamp recordings in behaving rodents

BackgroundIn vivo patch-clamp recording techniques provide access to the sub- and suprathreshold membrane potential dynamics of individual neurons during behavior. However, maintaining recording stability throughout behavior is a significant challenge, and while methods for head restraint are commonly used to enhance stability, behaviorally related brain movement relative to the skull can severely impact the success rate and duration of whole-cell patch-clamp recordings. New methodWe developed a low-cost, biocompatible, and 3D-printable cranial implant capable of locally stabilizing brain movement, while permitting equivalent access to the brain when compared to a conventional craniotomy. ResultsExperiments in head-restrained behaving mice demonstrate that the cranial implant can reliably reduce the amplitude and speed of brain displacements, significantly improving the success rate of recordings across repeated bouts of motor behavior. Comparison with existing method(s)Our solution offers an improvement on currently available strategies for brain stabilization. Due to its small size, the implant can be retrofitted to most in vivo electrophysiology recording setups, providing a low cost, easily implementable solution for increasing intracellular recording stability in vivo. ConclusionsBy facilitating stable whole-cell patch-clamp recordings in vivo, biocompatible 3D printed implants should accelerate the investigation of single neuron computations underlying behavior.

An existing pile efficiency method for the design of lateral new pile behavior in sites with existing piles

Foundation reuse is the development trend of sustainable engineering construction. However, the reuse of existing piles as rigid inclusions and their contribution to newly constructed piles (new piles) under different new and existing pile spacings are still insufficiently understood. In this paper, a series of numerical investigations were conducted based on centrifuge tests to examine the effect of existing piles on the lateral behavior of new piles under different pile spacings. The existing pile efficiency that reflects the contribution of existing piles to the lateral capacity of new piles was analyzed, and it was shown that the impact of existing piles decays exponentially with the pile spacing between new and existing piles. Beyond the spacing of 6 D ( D: the diameter of new piles), the lateral new pile–soil–existing pile interaction can be neglected. A parametric study was subsequently performed to quantify the existing pile efficiency under different variables, including the new pile-head restraint, loading displacement, bending stiffness, load eccentricity, embedded depth, and soil properties. Finally, an existing pile efficiency-based method for the estimation of the lateral capacity of new piles was proposed, which provides an efficient way to design laterally loaded new piles in sites with existing piles.