Superficial Regions Research Articles

English

Superficial temporal space lies between the temporal fasciae. Abscess in the temporal and infratemporal space is very rare. They develop as a result of the extraction of infected maxillary molars. Temporal space infections or abscesses can be seen in the superficial or deep temporal regions. A 65 - year - old male patient reported with a complaint of painful swelling over the right cheek and restricted mouth opening with a history of extraction of second mandibular molar before four weeks. On examination, an ill-defined diffuse swelling was seen. Treatment was started with IV empirical antibiotics and planned for surgical drainage. Surgical drainage of the abscess in the temporal space was done along with debridement of the necrosed temporalis muscle. Infections of the maxillofacial region are of great significance to general dentists and maxillofacial surgeons. They are of clinical importance as they are commonly encountered, and are also challenging as timely intervention is needed to prevent fatal complications. The infections arising from the tooth are initially confined to the alveolar bone and surrounding periosteum. They spread along the path of the least resistance to the cortical plates. Once the infection penetrates the cortical plates, they reach the muscle plane.1 If the infection perforated is above the muscle attachments, it’s confined to an intraoral abscess. If the cortical plates are perforated below the muscular attachments, extraoral swelling develops. The next barrier is the periosteum which is strong and elastic in nature. Once the periosteum is breached, infections reach the soft tissue planes, the fascia. Most of the infections are confined to a particular space and the surrounding fascia. Based on the toxins produced by the microorganisms, the infection can spread to adjacent spaces and even retrograde. Common deep space infections are Ludwig's angina followed by peritonsillar, submandibular, and parotid abscesses. 2 Infratemporal and temporal space infections are rarely compared to other deep space infections. Many etiological factors form the base for the infections of deep spaces, dental caries, extraction of infected, non-infected tooth maxillary sinusitis, tonsillitis, maxillary sinus fracture, temporomandibular arthroscopy, drug-induced infections. Infections of odontogenic origin, spreading along infratemporal and temporal space are most common with maxillary molars followed by mandibular molars. We report a case of retrograde spread of buccal space infection into temporal space secondary to mandibular tooth extraction.

Long-term in vivo two-photon imaging of the neuroinflammatory response to intracortical implants and micro-vessel disruptions in awake mice

Our understanding of biomaterials in the brain have been greatly enhanced by advancements in in vivo imaging technologies such as two-photon microscopy. However, when applied to chronic studies, two-photon microscopy enables high-resolution imaging only in superficial regions due to inflammatory responses introduced by the craniotomy and insertion of foreign biomaterials. Microprisms provide a unique vertical view from brain surface to ~1 mm deep or more (depending on the size of the microprisms) which may break through this limitation on imaging depth. Although microprism has been used in the field of neuroscience, the in vivo foreign body responses to the microprism implant have yet to be fully elucidated. This is of important concern in broader applications of this approach, especially for neuroinflammation-sensitive studies. In this work, we first assessed the activation of microglia/macrophages for 16 weeks after microprism implantation using two-photon microscopy in awake CX3CR1-GFP mice. The imaging window became clear from bleedings after ~2 weeks and the maximum imaging distance (in the horizontal direction) stabilized at around 500 μm after ~5 weeks. We also quantified the microglial morphology from week 3 to week 16 post-implantation. Compared to non-implant controls, microglia near the microprism showed higher cell density, smaller soma, and shorter and less branched processes in the early-chronic phase. After week 5, microglial morphology further than 100 μm from the microprism was generally similar to microglia in the control group. In addition, time-lapse imaging confirmed that microglial processes were surveying normally from week 3, even for microglia as close as 50 μm away. These morphological analyses and dynamic imaging results suggest that microglia around chronically implanted microprism eventually exhibit inactive phenotypes. Next, we examined microglial/macrophage responses following laser induced micro-vessel disruptions as an example application of microprism implantation for neuroinflammation related studies. Through the microprism, we captured microglial/macrophage polarization and migration, as well as blood flow changes after the insult for additional 16 weeks. To our surprise, microglia/macrophage aggregation around the insult site was sustained over the 16-week observation period. This work demonstrates the feasibility of using microprisms for long-term characterizations of inflammatory responses to other injuries including implantable devices at deeper depths than that achievable by conventional two-photon microscopy.

Miniature microscopes for manipulating and recording in vivo brain activity.

Here we describe the development and application of miniature integrated microscopes (miniscopes) paired with microendoscopes that allow for the visualization and manipulation of neural circuits in superficial and subcortical brain regions in freely behaving animals. Over the past decade the miniscope platform has expanded to include simultaneous optogenetic capabilities, electrically-tunable lenses that enable multi-plane imaging, color-corrected optics, and an integrated data acquisition platform that streamlines multimodal experiments. Miniscopes have given researchers an unprecedented ability to monitor hundreds to thousands of genetically-defined neurons from weeks to months in both healthy and diseased animal brains. Sophisticated algorithms that take advantage of constrained matrix factorization allow for background estimation and reliable cell identification, greatly improving the reliability and scalability of source extraction for large imaging datasets. Data generated from miniscopes have empowered researchers to investigate the neural circuit underpinnings of a wide array of behaviors that cannot be studied under head-fixed conditions, such as sleep, reward seeking, learning and memory, social behaviors, and feeding. Importantly, the miniscope has broadened our understanding of how neural circuits can go awry in animal models of progressive neurological disorders, such as Parkinson’s disease. Continued miniscope development, including the ability to record from multiple populations of cells simultaneously, along with continued multimodal integration of techniques such as electrophysiology, will allow for deeper understanding into the neural circuits that underlie complex and naturalistic behavior.

Craniotomy Procedure for Visualizing Neuronal Activities in Hippocampus of Behaving Mice.

Imaging neuronal activities at single-cell resolution in awake behaving animals is a very powerful approach for the investigation of neural circuit functions in systems neuroscience. However, high absorbance and scattering of light in mammalian tissue limit intravital imaging mostly to superficial brain regions, leaving deep-brain areas, such as the hippocampus, out of reach for optical microscopy. In this video, we show the preparation and implantation of the custom-made imaging window to enable chronic in vivo imaging of the dorsal hippocampal CA1 region in head-fixed behaving mice. The custom-made window is supplemented with an infusion cannula that allows targeted delivery of viral vectors and drugs to the imaging area. By combining this preparation with wide-field imaging, we performed a long-term recording of neuronal activity using a fluorescent calcium indicator from large subsets of neurons in behaving mice over several weeks. We also demonstrated the applicability of this preparation for voltage imaging with single-spike resolution. High-performance genetically encoded indicators of neuronal activity and scientific CMOS cameras allowed the recurrent visualization of subcellular morphological details of single neurons at high temporal resolution. We also discuss the advantages and potential limitations of the described method and its compatibility with other imaging techniques.

The use of bolus in postmastectomy radiation therapy for breast cancer: A systematic review.

Post mastectomy radiation therapy (PMRT) reduces locoregional recurrence (LRR) and breast cancer mortality for selected patients. Bolus overcomes the skin-sparing effect of external-beam radiotherapy, ensuring adequate dose to superficial regions at risk of local recurrence (LR). This systematic review summarizes the current evidence regarding the impact of bolus on LR and acute toxicity in the setting of PMRT. 27 studies were included. The use of bolus led to higher rates of acute grade 3 radiation dermatitis (pooled rates of 9.6% with bolus vs. 1.2% without). Pooled crude LR rates from thirteen studies (n = 3756) were similar with (3.5%) and without (3.6%) bolus. Bolus may be indicated in cases with a high risk of LR in the skin, but seems not to be necessary for all patients. Further work is needed to define the role of bolus in PMRT.

Significant increases of the amygdala between immediate and late postpartum: Pronounced effects within the superficial subregion.

Research exploring the underlying neuroanatomical correlates of early motherhood seems to suggest that the period after giving birth is marked by tissue increases in the mother's brain. While some studies point to the amygdala as one of the areas undergoing postpartum changes, existing analyses did not discriminate between the different subregions of this functionally heterogeneous structure. Thus, to further extend this understudied field of research and to better understand the potential role of the amygdala when transitioning to motherhood, we applied an advanced region-of-interest technique that enabled us to analyze the amygdala as a whole as well as its different subareas, specifically the left and right centromedian (CM), laterobasal (LB), and superficial (SF) regions. Comparing the brains of 14 healthy women between immediate postpartum (within 1-2days of childbirth) and late postpartum (at 4-6weeks after childbirth), we revealed increases of the amygdala. However, effects manifested differentially across subareas, with particularly strong effects for the SF region, moderate effects for the CM region, and no effects for the LB region. These findings might reflect region-specific adaptations of the mother's brain tuning into the distinct and ever-changing needs of a newborn, either as a cause for it or as a consequence thereof.

Effect of elbow joint angles on electromyographic activity versus force relationships of synergistic muscles of the triceps brachii.

The electromyographic (EMG) activity and force relationship, i.e. EMG-force relationship, is a valuable indicator of the degree of the neuromuscular activation during isometric force production. However, there is minimal information available regarding the EMG-force relationship of individual triceps brachii (TB) muscles at different elbow joint angles. This study aimed to compare the EMG-force relationships of the medial (TB-Med), lateral (TB-Lat), and long heads (TB-Long) of the TB. 7 men and 10 women performed force matching isometric tasks at 20%, 40%, 60%, and 80%maximum voluntary contraction (MVC) at 60°, 90°, and 120° of extension. During the submaximal force matching tasks, the surface EMG signals of the TB-Med, TB-Lat, and TB-Long were recorded and calculated the root mean square (RMS). RMS of each force level were then normalized by RMS at 100%MVC. For the TB-Med, ultrasonography was used to determine the superficial region of the muscle that faced the skin surface to minimize cross-talk. The joint angle was monitored using an electrogoniometer. The elbow extension force, elbow joint angle, and surface EMG signals were simultaneously sampled at 2 kHz and stored on a personal computer. The RMS did not significantly differ between the three muscles, except between the TB-Med and TB-Lat during 20%MVC at 60°. The RMS during force levels of ≥ 60%MVC at 120° was significantly lower than that at 60° or 90° for each muscle. The sum of difference, which represents the difference in RMS from the identical line, did not significantly differ in any of the assessed muscles in the present study. This suggests that a relatively smaller neuromuscular activation could be required when the elbow joint angle was extended. However, neuromuscular activation levels and relative force levels were matched in all three TB synergists when the elbow joint angle was at 90° or a more flexed position.

Sliding contact accelerates solute transport into the cartilage surface compared to axial loading

The objectives of this study were: first, to compare solute uptake driven by sliding to cyclic uniaxial compression. And secondly, to evaluate the role of the superficial region on passive diffusion to determine if mechanical action is merely overcoming the low permeability of the superficial region or exceeding equilibrium capacity of the tissue. Tests were performed on osteochondral plugs under two types of conditions: cyclic loading (sliding vs axial compression) and unloaded passive diffusion (intact vs superficial zone removed). The articular surfaces were exposed to a fluorescent bath and uptake was quantified from the surface to the subchondral bone using fluorescent microscopy. Primary outcome measures were total mass transfer, mass transfer rate, and surface partition factor. Mass transfer was 2.1-fold higher at 0.5h for sliding compared to uniaxial compression (p=0.004). This increased to 4.4-fold at 2h (p=0.002). Solute transport for both loading conditions at 2h had reached or exceeded intact passive diffusion at 12h. Total mass transport and mass transport per hour was higher in samples without the superficial region compared to intact samples at equilibrium. Rate of mass transfer was not declining for samples subject to sliding indicating solute uptake induced by sliding would exceed passive tissue capacity. These results are the first to quantify solute uptake between two components of joint articulation. The study demonstrates that sliding is a larger driver of solute transport compared to cyclic uniaxial compression. This has implications for cell nutrition, tissue engineering and biochemical signaling.

Temperature abetted synthesis of novel magnesium stannate nanoparticles assisted for nanomolar level detection of hazardous flavonoid in biological samples

Fabrication of temperature-influenced nanoparticles over the superficial region of glassy carbon electrode (GCE) stimulates the electrocatalytic activity owing to their morphology, defective sites, and higher active surface area, etc. In this regard, we have fabricated annealed magnesium stannate nanoparticles (Mg2SnO4 NPs) on GCE for nanomolar level detection of hazardous flavoring and pharmaceutical compound Rutin (RT). To analyze the impact of temperature, we have compared annealed Mg2SnO4 NPs with unannealed magnesium stannate hydrate (MgSnO3·3H2O) particles. The physicochemical properties of synthesized materials were characterized with different microscopic and spectroscopic techniques. From these studies, annealed Mg2SnO4 NPs formed purely without any flith and existence of water molecules as compared to unannealed MgSnO3·3H2O. Moreover as fabricated, Mg2SnO4 NPs/GCE outcomes with higher redox behavior compared to other electrodes in presence of RT at optimized working buffer (pH = 7.0). Interestingly, the electrode successfully established a dual wider linear response (0.062–34.8 & 34.8–346.8 µM) with a nanomolar detection limit (1 nM) and higher sensitivity. The practicability analysis of the proposed sensor also affords excellent selectivity, reproducibility, repeatability, reversibility, and storage stability. Furthermore, the real sample analysis was carried out in blood and orange samples fallout with better recovery results.

Roles of Lipids in the Permeability Barriers of Skin and Oral Mucosa

PubMed searches reveal much literature regarding lipids in barrier function of skin and less literature on lipids in barrier function of the oral mucosa. In terrestrial mammals, birds, and reptiles, the skin’s permeability barrier is provided by ceramides, fatty acids, and cholesterol in the outermost layers of the epidermis, the stratum corneum. This layer consists of about 10–20 layers of cornified cells embedded in a lipid matrix. It effectively prevents loss of water and electrolytes from the underlying tissue, and it limits the penetration of potentially harmful substances from the environment. In the oral cavity, the regions of the gingiva and hard palate are covered by keratinized epithelia that much resemble the epidermis. The oral stratum corneum contains a lipid mixture similar to that in the epidermal stratum corneum but in lower amounts and is accordingly more permeable. The superficial regions of the nonkeratinized oral epithelia also provide a permeability barrier. These epithelial regions do contain ceramides, cholesterol, and free fatty acids, which may underlie barrier function. The oral epithelial permeability barriers primarily protect the underlying tissue by preventing the penetration of potentially toxic substances, including microbial products. Transdermal drug delivery, buccal absorption, and lipid-related disease are discussed.

Diaphyseal aneurysmal bone cysts (ABCs) of long bones in extremities: Analysis of surgical management and comparison with metaphyseal lesions

IntroductionAneurysmal bone cysts (ABCs) are benign lesions of long bone metaphysis affecting mostly medullary region in younger age below 20 years of life. These may be originated rarely either in the cortex or in the superficial regions of diaphysis. The study highlighted the differences of diaphyseal lesions from the usual metaphyseal ones in view of their clinical, radiological and biological behavior and also discussed their management in brief. Material and methodsWe reviewed a total of 84 aneurysmal bone cysts over the past fourteen years (2004–2017) and evaluated their surgical outcomes retrospectively. Total ten lesions were diaphyseal cortical in location (group I), while 74 lesions were conventional metaphyseal type (group II). ResultsWe observed that cortical ABCs were occurred commonly in diaphysis of femur, humerus, tibia and radius while presentation was at an older age than metaphyseal type. Radiographically these were eccentric lesion and more prone for pathological fractures than conventional type. These are differentiated radiographically from other benign lesions but also mimicking malignant conditions including low grade surface osteosarcoma and telangiectatic osteosarcoma while resemble similar to these on histopathological examination (HPE). ConclusionBiological behavior of cortical lesions does not differ significantly than conventional type but these are more prone for pathological fractures so these eccentric cortical ABC lesions should be treated with adequate internal fixation along with curettage and bone grafting. Although incidence of cortical or surface variety of ABCs is rare but surgeons might evaluate its severity in view of aggressive benign or malignant lesions of diaphysis.

Cutaneous mucinosis in a Shar pei dog: Case report

Cutaneous mucinosis is a primary idiopathic dermatopathy that occurs in dogs of the Shar pei breed, characterized by excessive deposition of mucin in the dermis that leads to the presentation of skin folds, and in more severe cases the formation of vesicles or blisters. Hyaluronic acid has been identified as the main component of mucin, however the etiopathogenesis, prevention and treatment of this disease have not yet been fully elucidated. This paper reports a 3-year-old Shar pei dog, diagnosed with cutaneous mucinosis. On physical examination, multiple vesicles containing transparent and viscous fluid and hypotrichosis were observed in the ventral region of the neck, armpits, bilateral flank, perianal and in the distal portion of the limbs. In the pelvic limbs there was also the presence of edema. The affected skin was swollen, thickened and negative at Godet's sign. Blood tests, scrapes and skin cytology were performed. Blood tests did not show any significant alterations, as well as scraping and skin cytology showed negative results. Based on these results, it was decided to perform a skin biopsy and histopathological analysis. Intense and diffuse myxomatous edema was observed, mainly in the most superficial and perianexal region, with the formation of mucin lakes, confirming the diagnosis. For treatment, prednisolone was prescribed at a dose of 1 mg / kg every 24 hours, for 7 days, reducing the dose until the drug was discontinued in 30 days. After 21 days of treatment, the patient had complete resolution of the lesions and itching. It was possible to conclude that cutaneous mucinosis is an exclusive dermatopathy of dogs of the Shar pei breed due to the intense genetic selection throughout the breed's history. The impact of high hyaluronic acid synthesis on the phenotype of these dogs is only partially known. In this way, many other sites and systemic effects of hyaluronic acid still need to be understood since this glycosaminoglycan is synthesized by several cells and can be found in various tissues and body fluids with varying concentrations.Hyaluronic acid, dogs, dermatopathy, mucin

Lifelong exercise is associated with more homogeneous motor unit potential features across deep and superficial areas of vastus lateralis

Motor unit (MU) expansion enables rescue of denervated muscle fibres helping to ameliorate age-related muscle atrophy, with evidence to suggest master athletes are more successful at this remodelling. Electrophysiological data has suggested MUs located superficially are larger than those located deeper within young muscle. However, the effects of ageing and exercise on MU heterogeneity across deep and superficial aspects of vastus lateralis (VL) remain unclear. Intramuscular electromyography was used to record individual MU potentials (MUPs) and near fibre MUPs (NFMs) from deep and superficial regions of the VL during 25% maximum voluntary contractions, in 83 males (15 young (Y), 17 young athletes (YA), 22 old (O) and 29 master athletes (MA)). MUP size and complexity were assessed using area and number of turns, respectively. Multilevel mixed effects linear regression models were performed to investigate the effects of depth in each group. MUP area was greater in deep compared with superficial MUs in Y (p<0.001) and O (p=0.012) but not in YA (p=0.071) or MA (p=0.653). MUP amplitude and NF MUP area were greater, and MUPs were more complex in deep MUPs from Y, YA and O (all p<0.05) but did not differ across depth in MA (all p>0.07). These data suggest MU characteristics differ according to depth within the VL which may be influenced by both ageing and exercise. A more homogenous distribution of MUP size and complexity across muscle depths in older athletes may be a result of a greater degree of age-related MU adaptations.

Characterization of Ti–Zr–V thin films deposited by DC and unipolar pulsed DC magnetron sputtering

Ternary Ti–Zr–V getter films with approximately equal atomic concentrations were deposited on oxygen free copper substrates by magnetron sputtering using DC and unipolar pulsed DC current modes. The thin film morphologies were studied using scanning electron microscopy, atomic force microscopy, while their chemical and phase compositions were investigated by energy dispersive spectroscopy and X-ray diffraction, respectively. The chemical states within the superficial regions of the films were characterized by X-ray photoelectron spectroscopy in ultra-high vacuum. The results indicate that both current modes promote formation of porous thin films, while the microstructure of the DC film is much finer than that of the unipolar pulsed DC film. Initially, the thin films were covered by oxides of Ti, Zr and V that are reduced upon annealing treatment; those within the DC film present faster reduction kinetics as compared with that of the unipolar pulsed DC film.

Evaluation of the surface dose for total body irradiation (TBI) technique with parallel-opposed anterior posterior geometry

AbstractAim:Total body irradiation (TBI) is an external radiotherapy technique in which the whole body including the superficial regions is required to receive the therapeutic dose. The purpose of this study is to evaluate the received surface dose during TBI technique.Methods and materials:The anterior/posterior (AP/PA) TBI was implemented with 18-MV photon beam at 312-cm treatment distance for human-like phantom. The GAFCHROMIC-EBT3 films were used for superficial dose measurements.Results and discussion:The percentage of surface-absorbed dose relative to the prescription point for 8 points of measurements was between 102·78–121·48% and 104·51–127·43% at 5 and 10 mm depth, respectively. In the chest wall region due to the presence of lung blocks, the absorbed dose was below the acceptable level, so an electron boost was required to increase the chest wall absorbed dose.Conclusions:According to the results, the implemented technique was able to deliver sufficient dose to the shallow surface of phantom’s body.

Differential expression of GluN2 NMDA receptor subunits in the dorsal horn of male and female rats

ABSTRACT N-methyl-D-aspartate receptors (NMDARs) are excitatory ionotropic glutamate receptors expressed throughout the CNS, including in the spinal dorsal horn. The GluN2 subtypes of NMDAR subunit, which include GluN2A, GluN2B, and GluN2D in the dorsal horn, confer NMDARs with structural and functional variability, enabling heterogeneity in synaptic transmission and plasticity. Despite essential roles for NMDARs in physiological and pathological pain processing, the distribution and function of these specific GluN2 isoforms across dorsal horn laminae remain poorly understood. Surprisingly, there is a complete lack of knowledge of GluN2 expression in female rodents. We, therefore, investigated the relative expression of specific GluN2 variants in the dorsal horn of lumbar (L4/L5) spinal cord from both male and female rats. In order to detect synaptic GluN2 isoforms, we used pepsin antigen-retrieval to unmask these highly cross-linked protein complexes. We found that GluN2B and GluN2D are preferentially localized to the pain-processing superficial regions of the dorsal horn in males, while only GluN2B is predominantly localized to the superficial dorsal horn of female rats. The GluN2A subunit is diffusely localized to neuropil throughout the dorsal horn of both males and females, while GluN2B and GluN2D immunolabelling are found both in the neuropil and on the soma of dorsal horn neurons. Finally, we identified an unexpected enhanced expression of GluN2B in the medial division of the superficial dorsal horn, but in males only. These sex-specific localization patterns of GluN2-NMDAR subunits across dorsal horn laminae have significant implications for the understanding of divergent spinal mechanisms of pain processing.

Contouring strategies to improve the tensile properties and quality of EBM printed Inconel 625 parts

Abstract This work systematically analyzes the influence of rough surfaces and porous subsurfaces in electron beam melting (EBM) printed components. Consequently, it applies various contouring strategies to improve the tensile properties of EBM printed Inconel 625 alloy parts. It is shown that no contouring (i.e., only hatching) creates a rough surface with numerous surface voids (as translated to surface notches). Although the commercially used multi-spot contouring can smoothen the surface to some extent (∼34 %), it fails to create a defect-free superficial region by leaving ∼25 % surface voids (translated to large surface notches) and ∼4 % subsurface porosity. These superficial defects form due to an interrupted shrinkage, occurring on the surface and in the contouring region. In contrast, optimal post-hatching high energy continuous contouring creates a thick and consistent post-hatching track that can successfully reconsolidate surface voids remaining from the hatching step. In comparison with the multi-spot contouring, this reduces the surface and subsurface porosity down to ∼10 % and ∼0.4 %, respectively, and hence increases the apparent stiffness by ∼140 %, tensile strength by ∼105 % and elongation by ∼260 %. This nearly reaches the mechanical properties of the conventionally machined parts (UTS ∼635 ± 20 MPa and elongation ∼50 ± 2 %).

Identification and quantification of neuronal ensembles in optical imaging experiments

Recent technical advances in molecular biology and optical imaging have made it possible to record from up to thousands of densely packed neurons in superficial and deep brain regions in vivo, with cellular subtype specificity and high spatiotemporal fidelity. Such optical neurotechnologies are enabling increasingly fine-scaled studies of neuronal circuits and reliably co-active groups of neurons, so-called ensembles. Neuronal ensembles are thought to constitute the basic functional building blocks of brain systems, potentially exhibiting collective computational properties. While the technical framework of in vivo optical imaging and quantification of neuronal activity follows certain widely held standards, analytical methods for study of neuronal co-activity and ensembles lack consensus and are highly varied across the field. Here we provide a comprehensive step-by-step overview of theoretical, experimental, and analytical considerations for the identification and quantification of neuronal ensemble dynamics in high-resolution in vivo optical imaging studies.

Extended-amygdala intrinsic functional connectivity networks: A population study.

Pre‐clinical and human neuroimaging research implicates the extended‐amygdala (ExtA) (including the bed nucleus of the stria terminalis [BST] and central nucleus of the amygdala [CeA]) in networks mediating negative emotional states associated with stress and substance‐use behaviours. The extent to which individual ExtA structures form a functionally integrated unit is controversial. We utilised a large sample (n > 1,000 healthy young adult humans) to compare the intrinsic functional connectivity networks (ICNs) of the BST and CeA using task‐free functional magnetic resonance imaging (fMRI) data from the Human Connectome Project. We assessed whether inter‐individual differences within these ICNs were related to two principal components representing negative disposition and alcohol use. Building on recent primate evidence, we tested whether within BST‐CeA intrinsic functional connectivity (iFC) was heritable and further examined co‐heritability with our principal components. We demonstrate the BST and CeA to have discrete, but largely overlapping ICNs similar to previous findings. We found no evidence that within BST—CeA iFC was heritable; however, post hoc analyses found significant BST iFC heritability with the broader superficial and centromedial amygdala regions. There were no significant correlations or co‐heritability associations with our principal components either across the ICNs or for specific BST‐Amygdala iFC. Possible differences in phenotype associations across task‐free, task‐based, and clinical fMRI are discussed, along with suggestions for more causal investigative paradigms that make use of the now well‐established ExtA ICNs.

Activation of Superficial and Deep Finger Flexors Through Transcutaneous Nerve Stimulation.

Functional electrical stimulation (FES) is a common technique to elicit muscle contraction and help improve muscle strength. Traditional FES over the muscle belly typically only activates superficial muscle regions. In the case of hand FES, this prevents the activation of the deeper flexor muscles which control the distal finger joints. Here, we evaluated whether an alternative transcutaneous nerve-bundle stimulation approach can activate both superficial and deep extrinsic finger flexors using a high-density stimulation grid. Transverse ultrasound of the forearm muscles was used to obtain cross-sectional images of the underlying finger flexors during stimulated finger flexions and kinematically-matched voluntary motions. Finger kinematics were recorded, and an image registration method was used to capture the large deformation of the muscle regions during each flexion. This deformation was used as a surrogate measure of the contraction of muscle tissue, and the regions of expanding tissue can identify activated muscles. The nerve-bundle stimulation elicited contractions in the superficial and deep finger flexors. Both separate and concurrent activation of these two muscles were observed. Joint kinematics of the fingers also matched the expected regions of muscle contractions. Our results showed that the nerve-bundle stimulation technique can activate the deep extrinsic finger flexors, which are typically not accessible via traditional surface FES. Our nerve-bundle stimulation method enables us to produce the full range of motion of different joints necessary for various functional grasps, which could benefit future neuroprosthetic applications.