TSANet: multibranch attention deep neural network for classifying tactile selective attention in brain-computer interfaces

Brain-computer interfaces (BCIs) enable communication between the brain and a computer and electroencephalography (EEG) has been widely used to implement BCIs because of its high temporal resolution and noninvasiveness. Recently, a tactile-based EEG task was introduced to overcome the current limitations of visual-based tasks, such as visual fatigue from sustained attention. However, the classification performance of tactile-based BCIs as control signals is unsatisfactory. Therefore, a novel classification approach is required for this purpose. Here, we propose TSANet, a deep neural network, that uses multibranch convolutional neural networks and a feature-attention mechanism to classify tactile selective attention (TSA) in a tactile-based BCI system. We tested TSANet under three evaluation conditions, namely, within-subject, leave-one-out, and cross-subject. We found that TSANet achieved the highest classification performance compared with conventional deep neural network models under all evaluation conditions. Additionally, we show that TSANet extracts reasonable features for TSA by investigating the weights of spatial filters. Our results demonstrate that TSANet has the potential to be used as an efficient end-to-end learning approach in tactile-based BCIs.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-023-00309-4.

Low-Loss Pogo Pin Probe Card with a Coupling Isolation Structure up to 50 GHz

A design for a millimeter wave RF probe card that removes resonance is proposed. The designed probe card optimizes the position of the ground surface and the signal pogo pins to resolve the resonance and signal loss issues that occur when connecting a dielectric socket and a PCB. At millimeter wave frequencies, the height of the dielectric socket and pogo pin matches the length of half a wavelength, allowing the socket to act as a resonator. When the leakage signal from the PCB line is coupled to the 2.9 mm high socket with pogo pins, resonance at a frequency of 28 GHz is generated. The probe card uses the ground plane as a shielding structure to minimize this resonance and radiation loss. The importance of the signal pin location is verified via measurements in order to address the discontinuity caused by field polarity switching. A probe card fabricated using the proposed technique exhibits an insertion loss performance of -8 dB up to 50 GHz and eliminates resonance. A signal with an insertion loss of -3.1 dB can be transmitted to a system-on-chip in a practical chip test.

First Observation of the β3αp Decay of ^{13}O via β-Delayed Charged-Particle Spectroscopy

The β-delayed proton decay of ^{13}O has previously been studied, but the direct observation of β-delayed 3αp decay has not been reported. Rare 3αp events from the decay of excited states in ^{13}N^{⋆} provide a sensitive probe of cluster configurations in ^{13}N. To measure the low-energy products following β-delayed 3αp decay, the Texas Active Target (TexAT) time projection chamber was employed using the one-at-a-time β-delayed charged-particle spectroscopy technique at the Cyclotron Institute, Texas A&M University. A total of 1.9×10^{5} ^{13}O implantations were made inside the TexAT time projection chamber. A total of 149 3αp events were observed, yielding a β-delayed 3αp branching ratio of 0.078(6)%. Four previously unknown α-decaying excited states were observed in ^{13}N at 11.3, 12.4, 13.1, and 13.7 MeV decaying via the 3α+p channel.

First Direct Measurement Constraining the ^{34}Ar(α,p)^{37}K Reaction Cross Section for Mixed Hydrogen and Helium Burning in Accreting Neutron Stars

The rate of the final step in the astrophysical αp process, the ^{34}Ar(α,p)^{37}K reaction, suffers from large uncertainties due to a lack of experimental data, despite having a considerable impact on the observable light curves of x-ray bursts and the composition of the ashes of hydrogen and helium burning on accreting neutron stars. We present the first direct measurement constraining the ^{34}Ar(α,p)^{37}K reaction cross section, using the Jet Experiments in Nuclear Structure and Astrophysics gas jet target. The combined cross section for the ^{34}Ar,Cl(α,p)^{37}K,Ar reaction is found to agree well with Hauser-Feshbach predictions. The ^{34}Ar(α,2p)^{36}Ar cross section, which can be exclusively attributed to the ^{34}Ar beam component, also agrees to within the typical uncertainties quoted for statistical models. This indicates the applicability of the statistical model for predicting astrophysical (α,p) reaction rates in this part of the αp process, in contrast to earlier findings from indirect reaction studies indicating orders-of-magnitude discrepancies. This removes a significant uncertainty in models of hydrogen and helium burning on accreting neutron stars.

An Investigation of Stochastic Variance Reduction Algorithms for Relative Difference Penalized 3D PET Image Reconstruction

Penalised PET image reconstruction algorithms are often accelerated during early iterations with the use of subsets. However, these methods may exhibit limit cycle behaviour at later iterations due to variations between subsets. Desirable converged images can be achieved for a subclass of these algorithms via the implementation of a relaxed step size sequence, but the heuristic selection of parameters will impact the quality of the image sequence and algorithm convergence rates. In this work, we demonstrate the adaption and application of a class of stochastic variance reduction gradient algorithms for PET image reconstruction using the relative difference penalty and numerically compare convergence performance to BSREM. The two investigated algorithms are: SAGA and SVRG. These algorithms require the retention in memory of recently computed subset gradients, which are utilised in subsequent updates. We present several numerical studies based on Monte Carlo simulated data and a patient data set for fully 3D PET acquisitions. The impact of the number of subsets, different preconditioners and step size methods on the convergence of regions of interest values within the reconstructed images is explored. We observe that when using constant preconditioning, SAGA and SVRG demonstrate reduced variations in voxel values between subsequent updates and are less reliant on step size hyper-parameter selection than BSREM reconstructions. Furthermore, SAGA and SVRG can converge significantly faster to the penalised maximum likelihood solution than BSREM, particularly in low count data.

Alpha transcranial alternating current stimulation reduces depressive symptoms in people with schizophrenia and auditory hallucinations: a double-blind, randomized pilot clinical trial

People with schizophrenia exhibit reduced alpha oscillations and frontotemporal coordination of brain activity. Alpha oscillations are associated with top-down inhibition. Reduced alpha oscillations may fail to censor spurious endogenous activity, leading to auditory hallucinations. Transcranial alternating current stimulation (tACS) at the alpha frequency was shown to enhance alpha oscillations in people with schizophrenia and may thus be a network-based treatment for auditory hallucinations. We conducted a double-blind, randomized, placebo-controlled pilot clinical trial to examine the efficacy of 10-Hz tACS in treating auditory hallucinations in people with schizophrenia. 10-Hz tACS was administered in phase at the dorsolateral prefrontal cortex and the temporoparietal junction with a return current at Cz. Patients were randomized to receive tACS or sham for five consecutive days during the treatment week (40 min/day), followed by a maintenance period, during which participants received weekly tACS (40 min/visit) or sham. tACS treatment reduced general psychopathology (p < 0.05, Cohen's d = -0.690), especially depression (p < 0.005, Cohen's d = -0.806), but not auditory hallucinations. tACS treatment increased alpha power in the target region (p < 0.05), increased the frequency of peak global functional connectivity towards 10 Hz (p < 0.05), and reduced left-right frontal functional connectivity (p < 0.005). Importantly, changes in brain functional connectivity significantly correlated with symptom improvement (p < 0.05). Daily 10 Hz-tACS increased alpha power and altered alpha-band functional connectivity. Successful target engagement reduced depression and other general psychopathology symptoms, but not auditory hallucinations. Considering existing research of 10Hz tACS as a treatment for major depressive disorder, our study demonstrates its transdiagnostic potential for treating depression.

A Fast Convergent Ordered-Subsets Algorithm With Subiteration-Dependent Preconditioners for PET Image Reconstruction

We investigated the imaging performance of a fast convergent ordered-subsets algorithm with subiteration-dependent preconditioners (SDPs) for positron emission tomography (PET) image reconstruction. In particular, we considered the use of SDP with the block sequential regularized expectation maximization (BSREM) approach with the relative difference prior (RDP) regularizer due to its prior clinical adaptation by vendors. Because the RDP regularization promotes smoothness in the reconstructed image, the directions of the gradients in smooth areas more accurately point toward the objective function's minimizer than those in variable areas. Motivated by this observation, two SDPs have been designed to increase iteration step-sizes in the smooth areas and reduce iteration step-sizes in the variable areas relative to a conventional expectation maximization preconditioner. The momentum technique used for convergence acceleration can be viewed as a special case of SDP. We have proved the global convergence of SDP-BSREM algorithms by assuming certain characteristics of the preconditioner. By means of numerical experiments using both simulated and clinical PET data, we have shown that the SDP-BSREM algorithms substantially improve the convergence rate, as compared to conventional BSREM and a vendor's implementation as Q.Clear. Specifically, SDP-BSREM algorithms converge 35%-50% faster in reaching the same objective function value than conventional BSREM and commercial Q.Clear algorithms. Moreover, we showed in phantoms with hot, cold and background regions that the SDP-BSREM algorithms approached the values of a highly converged reference image faster than conventional BSREM and commercial Q.Clear algorithms.

P11.40.A Clinicopathological Analysis of High risk Pituitary Adenomas According to the 2017 WHO Classification System for Pituitary Neuroendocrine Tumors (PitNET)

Background

The 2017 WHO classification of pituitary tumors has revealed “high-risk pituitary neuroendocrine tumors (PitNETs)”, which were known to have high probability for recurrence. Tumor invasion was not included in the pathological grading and classification due to frequent lack of proper pathologic assessment. However, it mentioned tumor invasion as an important prognostic feature in identifying clinically aggressive adenomas.

Material and Methods

We performed a retrospective review of a prospectively collected dataset from January 2018 to March 2021. Patient’s clinical presentation, radiologic features, pathologic findings, and clinical outcome were gathered. Inter-group analysis was performed for high-risk versus low-risk tumors, and invasive versus non-invasive tumors.

Results

Among total 116 cases of PitNETs, high-risk and low-risk tumors were identified in 32 and 84 cases, respectively. The inter-group comparison showed no differences in clinical presentation, radiologic features, pathologic findings, and clinical outcomes.Invasive and non-invasive tumors were identified in 49 and 67 cases, respectively. The invasive group tumors were more symptomatic ( 29 (59.2%) vs. 30 (44.8%), p= 0.031), with larger tumor size over 40mm (9 (18.4%) vs. 1 (1.5%), p = 0.002), and more likely to have Knosp grade higher than 3. The gross-total resection was less achievable (7 (14.3%) vs 26 (38.8%), p = 0.007) However, Ki-67 index showed no significantly difference between the invasive group and non-invasive group (2.0 vs 2.0 , p= 0.556).

Conclusion

According to our study results, the pathologic diagnosis of a high-risk tumor does not necessarily seem to properly reflect the clinical aggressiveness. Tumor invasion, however, seems to better represent the aggressive tumors that requires proper and active treatment.

Inflammation and tissue remodeling contribute to fibrogenesis in stricturing Crohn’s disease: image processing and analysis study

Background

Inflammation and structural remodeling may contribute to fibrogenesis in Crohn’s disease (CD). We quantified the immunoexpression of calretinin, CD34, and calprotectin as a surrogate for mucosal innervation, telocytes (interstitial cells playing a role in networking), and inflammation, respectively, and correlated them with bowel alterations in stricturing CD.

Methods

Primary resection specimens for ileal CD (n = 44, 31 stricturing CD, 13 inflammatory CD) were identified. Left-sided ulcerative colitis and trauma cases were used as controls. Proximal and distal margin and middle (diseased) sections were stained for calretinin, CD34, and calprotectin. Microscopic images were captured from the mucosa (calretinin), submucosa (calprotectin), and myenteric plexus (CD34), and the immunostaining was quantified using image processing and analysis. Bowel thickness at the corresponding sections were measured and correlated with the amount of immunoexpression.

Results

A total of 2,037 images were analyzed. In stricturing CD, submucosal alteration/thickening at the stricture site correlated with calprotectin staining and inversely correlated with calretinin staining at the proximal margin. Muscularis propria alteration/thickening at the stricture site correlated with mucosal calretinin staining at the proximal margin. Submucosal alteration/thickening at the proximal margin correlated with calretinin and CD34 staining at the proximal margin and inversely correlated with CD34 staining at the stricture site. Calretinin immunostaining at the distal margin was significantly higher in stricturing CD than the controls.

Conclusions

Inflammation and tissue remodeling appear to contribute to fibrogenesis in stricturing CD. Increased mucosal calretinin immunostaining distal to the diseased segment could be helpful in diagnosing CD in the right clinical context.

Attenuation Coefficient Estimation for PET/MRI With Bayesian Deep Learning Pseudo-CT and Maximum-Likelihood Estimation of Activity and Attenuation

A major remaining challenge for magnetic resonance-based attenuation correction methods (MRAC) is their susceptibility to sources of magnetic resonance imaging (MRI) artifacts (e.g., implants and motion) and uncertainties due to the limitations of MRI contrast (e.g., accurate bone delineation and density, and separation of air/bone). We propose using a Bayesian deep convolutional neural network that in addition to generating an initial pseudo-CT from MR data, it also produces uncertainty estimates of the pseudo-CT to quantify the limitations of the MR data. These outputs are combined with the maximum-likelihood estimation of activity and attenuation (MLAA) reconstruction that uses the PET emission data to improve the attenuation maps. With the proposed approach uncertainty estimation and pseudo-CT prior for robust MLAA (UpCT-MLAA), we demonstrate accurate estimation of PET uptake in pelvic lesions and show recovery of metal implants. In patients without implants, UpCT-MLAA had acceptable but slightly higher root-mean-squared-error (RMSE) than Zero-echotime and Dixon Deep pseudo-CT when compared to CTAC. In patients with metal implants, MLAA recovered the metal implant; however, anatomy outside the implant region was obscured by noise and crosstalk artifacts. Attenuation coefficients from the pseudo-CT from Dixon MRI were accurate in normal anatomy; however, the metal implant region was estimated to have attenuation coefficients of air. UpCT-MLAA estimated attenuation coefficients of metal implants alongside accurate anatomic depiction outside of implant regions.

P-655 Insulin like growth factor-1 levels in follicular fluids of patients with poor ovarian response undergoing in vitro fertilization

Study question

Does follicular fluid insulin like growth factor level (IGF-1) in poor responders (PR) differ from normoresponders? Is there a correlation between IGF-1 and IVF outcomes?

Summary answer

Follicular IGF-1 levels are decreased in poor-responders A positive correlation exists between IGF-1 and number of metaphase II (MII) oocytes, fertilized oocytes and transferred embryos

What is known already

IGFs are mainly synthesized in liver with growth hormone stimulation. IGF-1 component in follicular fluid has been reported to play a crucial role in follicular and embryonic development. In addition to previously reported positive correlation between follicular IGF-I levels and number of high quality embryos, a significant decrease in IGF-1 levels with PR and advanced maternal age has also been reported. GH supplementation in poor responders undergoing IVF has been suggested to improve IVF outcomes. A recent Cochrane analysis reported that GH slightly increases the number of oocytes retrieved and there is an uncertain effect on live birth rates (LBR).

Study design, size, duration

Study was designed prospectively. A power analysis, of 91% determined a need for 186 patients. Therefore 186 women undergoing IVF between October 2019 and December 2020 were included. 72 (%38,7) patients were assigned to PRs group according to Bologna criteria (BC) and 114 patients (%61.3) were recruited as controls. Antagonist protocol was used for controlled ovarian hyperstimulation. hCG was administered for ovulation trigger.

Participants/materials, setting, methods

Following the ovarian hyperstimulation follicular fluid samples were collected during oocyte retrieval. When the total desired number of patients was reached, frozen and preserved follicle fluids were thawed at room temperature. IGF-1 levels in samples were measured using hIGF-1 ELISA kit (BT®, China). Follicular IGF-1 levels in PRs were compared to normoresponders and correlation between IGF-1 levels and AMH levels, number of retrieved oocytes, MII and fertilized oocytes, transferred embriyos and LBR were evaluated.

Main results and the role of chance

Mean IGF-1 levels of normoresponders and Bologna subgroups (B1, B2, B3, B4) were 13.79±14.50 ng/ml vs 5.75±1.86, 5.47±2.83, 5.96±2.16 and 5.03±1.85 ng/ml respectively (p &lt; 0.001). There was no statistically significant difference in clinical pregnancy (CP) per transfer and LBR per transfer between normoresponders and PRs (CPR/ET: 55.1% vs 43.7%, p:0.375; 26.5% vs 12.5% , p: 0.257). In the ROC analysis for the prediction of collection of fewer than 4 oocytes at retrieval (according to BC definition of PR), statistically determined IGF-1 value was 7.02 with a sensitivity of 83% and a specificity of 38.6%. Patients with an IGF-1 value below 7.02 had a higher risk of having an oocyte number less than 4According to the results of Spearman's correlation analysis, IGF-1 levels were negatively correlated with age and number of previous failed cycles (r:-0.250, p:0,001; r:-0.153, p:0,039 respectively). IGF-1 levels were positively correlated with AMH levels, oocyte, MII oocyte, fertilized oocyte numbers and number of transferred embriyos (r: 0.221, p: 0.007; r: 0.283, p &lt; 0.001; r: 0.293, p &lt; 0.001; r: 0.282, p &lt; 0.001; r: 0.194, p: 0.008 respectively). There was a positive correlation between IGF-1 levels and cycle cancellation rates (r: 0.637, p &lt; 0,001). There was no correlation between IGF-1 levels and LBR (p:0.118).

Limitations, reasons for caution

Small number of patients was the main limitation of study.Results were not interpreted as LBR in all cases, as 21% (n:24) of the cases had still ongoing pregnancies

Wider implications of the findings

Detecting lower follicular levels of IGF-1 which plays a crucial role in GH activity may highligt the effect of GH supplementation in poor responders undergoing IVF in terms of improved outcomes. However, there is need for more solid data to employ GH in IVF treatment modalities of poor-responders.

Trial registration number

not applicable

Neutron-upscattering enhancement of the triple-alpha process

The neutron inelastic scattering of carbon-12, populating the Hoyle state, is a reaction of interest for the triple-alpha process. The inverse process (neutron upscattering) can enhance the Hoyle state’s decay rate to the bound states of ¹²C, effectively increasing the overall triple-alpha reaction rate. The cross section of this reaction is impossible to measure experimentally but has been determined here at astrophysically-relevant energies using detailed balance. Using a highly-collimated monoenergetic beam, here we measure neutrons incident on the Texas Active Target Time Projection Chamber (TexAT TPC) filled with CO₂ gas, we measure the 3α-particles (arising from the decay of the Hoyle state following inelastic scattering) and a cross section is extracted. Here we show the neutron-upscattering enhancement is observed to be much smaller than previously expected. The importance of the neutron-upscattering enhancement may therefore not be significant aside from in very particular astrophysical sites (e.g. neutron star mergers).

The triple-alpha process plays a role in nucleosynthesis, in the formation of ¹²C. Here, the authors discuss the rate and role of the neutron upscattering phenomenon on the triple-alpha process in a multi-step process.

Increasing Trend of Calretinin-Positive Mucosal Innervation from Aganglionic Zone toward Transition Zone in Hirschsprung's Disease

INTRODUCTION

 Diagnosis of very short-segment Hirschsprung's disease (vsHD) by rectal suction biopsy is challenging as its aganglionic zone (AZ) overlaps with physiologic hypoganglionic zone and calretinin-positive mucosal nerves may extend from the transition zone (TZ) into AZ. We studied whether an increasing trend/gradient of calretinin-positive mucosal nerves along the distance from AZ toward TZ aids in diagnosis of HD.

MATERIALS AND METHODS

 In this study, 46 rectal suction biopsies from non-HD and HD, and 15 pull-through specimens from short-segment HD were evaluated by mucosal calretinin immunostain (CI) and image processing and analysis (IPA) to measure pixel count (PC, the percentage of calretinin stained pixels in the mucosa). Consecutive longitudinal sections of proximal AZ toward distal TZ in HD pull-through specimens were utilized as a vsHD surrogate model. First, we studied variability of mucosal CI in non-HD biopsies along the distance from dentate line. Second, we determined a cutoff point of mucosal CI by IPA that separated non-HD versus HD and applied this cutoff to longitudinal sections from proximal AZ to distal TZ segments in HD pull-through specimens. Third, we studied whether an increasing trend of mucosal CI was universally observed in HD pull-through.

RESULTS

 Our findings included a significant variability in PC along the biopsy distance in non-HD cases. Positive mucosal CI was found in proximal AZ in 6 (43%) of 14 HD pull-through, among which 1 case lacked submucosal nerve hypertrophy in the proximal AZ. All 14 HD pull-through cases showed an increasing trend/gradient of PC from AZ toward TZ.

CONCLUSION

 Based on our findings, the presence or absence of mucosal CI positivity and submucosal nerve hypertrophy may not reliably diagnose vsHD in rectal suction biopsy. While we acknowledge that the density of mucosal innervation in variable contexts and anatomical locations is unknown and yet to be explored, our study suggests that an increasing trend of positive mucosal CI from AZ toward TZ by IPA might prove to be a useful tool for the diagnosis of vsHD in the future.

High Estimated 24-Hour Urinary Sodium Excretion Is Related to Symptomatic Knee Osteoarthritis: A Nationwide Cross-Sectional Population-Based Study

OBJECTIVES

High salt intake results in various harmful effects on human health including hypertension, cardiovascular disease, and reduced bone density. Despite this, there are very few studies in the literature that have investigated the association between sodium intake and osteoarthritis (OA). Therefore, we aimed to explore these associations in a Korean population.

METHODS

This study used cross-sectional data from adult subjects aged 50-75 years from two consecutive periods of the Korean National Health and Nutrition Examination Survey V-VII (2010-2011 and 2014-2016). The estimated 24-hour urinary sodium excretion (24HUNa) was used as a surrogate marker of salt intake. In the 2010-2011 dataset, knee OA (KOA) was defined as the presence of the radiographic features of OA and knee pain. The association between KOA and salt intake was analysed using univariable and multivariable logistic regression methods. For the sensitivity analysis, the same procedures were conducted on subjects with self-reported OA (SR-OA) with knee pain in the 2010-2011 dataset and any site SR-OA in the 2014-2016 dataset.

RESULTS

Subjects with KOA had significantly lower energy intake, but higher 24HUNa than those without KOA. The restricted cubic spline plots demonstrated a J-shaped distribution between 24HUNa and prevalent KOA. When 24HUNa was stratified into five groups (<2, 2-3, 3-4, 4-5 and ≥5 g/day), subjects with high sodium intake (≥5 g/day) had a higher risk of KOA (odds ratio [OR] = 1.64, 95% confidence interval [CI] 1.03-2.62) compared to the reference group (3-4 g/day) after adjusting for covariates. The sensitivity analysis based on SR-OA with knee pain showed that high sodium intake was also significantly associated with increased prevalence of OA (OR = 1.84, 95% CI 1.10-3.10) compared with the reference group. Regarding SR-OA at any site in the 2014-2016 dataset, estimated 24HUNa showed a significantly positive association with the presence of SR-OA after adjusting for potential confounders.

CONCLUSIONS

This nationwide Korean representative study showed a significant association between symptomatic KOA and high sodium intake (≥5 g/day). Avoidance of a diet high in salt might be beneficial as a non-pharmacologic therapy for OA.

Tumor immune microenvironment is influenced by frameshift mutations and tumor mutational burden in gastric cancer

PURPOSE

Immunoscore can effectively predict prognosis in patients with colon cancer; however, its clinical application is limited. We modified the Immunoscore and created a tumor immune microenvironment (TIM) classification system for gastric carcinoma. Unlike previous studies that used small sample sizes or focused on particular immune-cell subtypes, our simplified system enables pathologists to classify gastric carcinomas intuitively using H&E-stained sections.

METHODS

Samples from 326 patients with advanced gastric carcinoma were reviewed and analyzed by pathologists using simple determination and digital image analysis. Comprehensive results of cancer-panel sequencing, Epstein-Barr‒virus (EBV) status, and PD-L1, HER2, ATM, PTEN, MET, FGFR2, and EGFR immunohistochemistry were evaluated with respect to the TIM class.

RESULTS

The TIM was classified as "hot" (n = 22), "immunosuppressed" (n = 178), "excluded" (n = 83), or "cold" (n = 43). TIM category was significantly associated with numbers of frameshift mutations (P < 0.001) and high tumor mutational burden (P < 0.004), and predicted overall survival. It was also significantly associated with age, histological type, degree of fibrosis, PD-L1 expression, loss of ATM and PTEN expression (P < 0.001), sex, EBV positivity, and HER2 overexpression (P < 0.04). "Hot" tumors were frequent in PD-L1 expressing and EBV-positive samples, and in those with ATM and PTEN loss. "Excluded" tumors were frequent in HER2-positive cases, whereas "cold" tumors were more frequent in younger patients with poorly cohesive histology and high fibrosis levels.

CONCLUSIONS

TIM classification system for gastric carcinoma has prognostic significance and results in classes that are associated with molecular characteristics.

Artificial Intelligence in PET: An Industry Perspective

Artificial intelligence (AI) has significant potential to positively impact and advance medical imaging, including positron emission tomography (PET) imaging applications. AI has the ability to enhance and optimize all aspects of the PET imaging chain from patient scheduling, patient setup, protocoling, data acquisition, detector signal processing, reconstruction, image processing, and interpretation. AI poses industry-specific challenges which will need to be addressed and overcome to maximize the future potentials of AI in PET. This article provides an overview of these industry-specific challenges for the development, standardization, commercialization, and clinical adoption of AI and explores the potential enhancements to PET imaging brought on by AI in the near future. In particular, the combination of on-demand image reconstruction, AI, and custom-designed data-processing workflows may open new possibilities for innovation which would positively impact the industry and ultimately patients.

Transcranial alternating current stimulation entrains alpha oscillations by preferential phase synchronization of fast-spiking cortical neurons to stimulation waveform

Computational modeling and human studies suggest that transcranial alternating current stimulation (tACS) modulates alpha oscillations by entrainment. Yet, a direct examination of how tACS interacts with neuronal spiking activity that gives rise to the alpha oscillation in the thalamo-cortical system has been lacking. Here, we demonstrate how tACS entrains endogenous alpha oscillations in head-fixed awake ferrets. We first show that endogenous alpha oscillations in the posterior parietal cortex drive the primary visual cortex and the higher-order visual thalamus. Spike-field coherence is largest for the alpha frequency band, and presumed fast-spiking inhibitory interneurons exhibit strongest coupling to this oscillation. We then apply alpha-tACS that results in a field strength comparable to what is commonly used in humans (<0.5 mV/mm). Both in these ferret experiments and in a computational model of the thalamo-cortical system, tACS entrains alpha oscillations by following the theoretically predicted Arnold tongue. Intriguingly, the fast-spiking inhibitory interneurons exhibit a stronger entrainment response to tACS in both the ferret experiments and the computational model, likely due to their stronger endogenous coupling to the alpha oscillation. Our findings demonstrate the in vivo mechanism of action for the modulation of the alpha oscillation by tACS.

Perinatal exposure to di-(2-ethylhexyl) phthalate induces hepatic lipid accumulation mediated by diacylglycerol acyltransferase 1

INTRODUCTION

Di-(2-ethylhexyl) phthalate (DEHP) is a commonly used plasticizer in consumer products and medical devices. It is also suspected to exacerbate the development of fatty liver. However, the mechanisms underlying excessive lipid synthesis and its deposition in the liver are yet to be identified. This study was aimed to evaluate the molecular mechanisms of hepatic lipid accumulation in adult male offspring after perinatal exposure to DEHP.

METHOD

Corn oil and DEHP (0.75 mg/kg/day) were administered once per day to dam from gestation day 6 to postnatal day (PND) 21 by oral gavage. After the weaning period, DEHP treated male pups were categorized into early life stage- and lifelong period group. Male rats both control and early life stage group administered corn oil, and lifelong period group administered DEHP from PND 22 to 70. Histological examination and triglyceride (TG) levels in the liver were analyzed. Expressions of transcription factors associated with lipid accumulation in the liver were analyzed.

RESULTS

Both early life stage- and lifelong period group, hepatic TG levels, and mRNA and protein expression of diacylglycerol acyltransferase 1 (DGAT1) were significantly higher than control (TG: all p < 0.05, mRNA & protein: p < 0.05 and p < 0.001, respectively). The average body weight from PND 35 to 63, and mRNA and protein expression of sterol regulatory element binding protein 1c in lifelong period group were significantly lower than control (all p < 0.05); however, alanine transaminase were significantly higher than control (p < 0.01).

CONCLUSION

Perinatal exposure to DEHP may induce the hepatic lipid accumulation through up-regulation of DGAT1 expression.

Transcranial Alternating Current Stimulation Reduces Network Hypersynchrony and Persistent Vertigo

OBJECTIVES

Persistent oscillating vertigo that occurs after entrainment to periodic motion is known as Mal de Débarquement Syndrome (MdDS). Down-modulation of this oscillating vertigo is associated with reduction in long-range resting-state functional connectivity between fronto-parieto-occipital regions. In order to determine the association between this oscillating vertigo and hypersynchrony as measured by the auditory steady-state response (ASSR), we investigated the differences in ASSR between individuals with MdDS and healthy controls as well as the change in ASSR in individuals with MdDS before and after treatment with transcranial alternating current stimulation (tACS).

MATERIALS AND METHODS

Individuals with treatment refractory MdDS lasting at least six months received single administrations of fronto-parieto-occipital tACS in an "n-of-1" double-blind randomized design: alpha-frequency in-phase, alpha-frequency antiphase, and gamma frequency antiphase control. The treatment protocol that led to the most acute reduction in symptoms and improved balance was administered for 10-12 sessions given over three days (each session 20-min at 2-4 mA).

RESULTS

Twenty-four individuals with MdDS participated (mean age 53.0 ± 11.8 years [range: 22-66 years, median: 57.0 years]; mean duration of illness 38.6 ± 53.4 months [range: 6-240 months, median: 18.0 months]). Individuals with MdDS had elevated ASSR compared to healthy controls at baseline (t₁₁  = 5.95, p < 0.001). There was a significant decrease in the 40 Hz-ASSR response between responders compared to nonresponders to tACS (t-test, t₁₅  = -2.26, p = 0.04). Both in-phase and anti-phase alpha tACS lead to symptom improvement but only antiphase alpha-tACS led to a significant decrease of 40 Hz-ASSR (t-test, t₁₂  = -9.6, p < 0.001).

CONCLUSIONS

Our findings suggest that tACS has the potential to reduce network-level hypersynchrony and pathological susceptibility to entrainment by sensory input. To the best of our knowledge, this is the first successful demonstration of desynchronization by noninvasive brain stimulation leading to reduced vertigo. Other disease states associated with pathological functional coupling of neuronal networks may similarly benefit from this novel approach.

Pinging the brain with transcranial magnetic stimulation reveals cortical reactivity in time and space

BACKGROUND

Single-pulse transcranial magnetic stimulation (TMS) elicits an evoked electroencephalography (EEG) potential (TMS-evoked potential, TEP), which is interpreted as direct evidence of cortical reactivity to TMS. Thus, combining TMS with EEG can be used to investigate the mechanism underlying brain network engagement in TMS treatment paradigms. However, controversy remains regarding whether TEP is a genuine marker of TMS-induced cortical reactivity or if it is confounded by responses to peripheral somatosensory and auditory inputs. Resolving this controversy is of great significance for the field and will validate TMS as a tool to probe networks of interest in cognitive and clinical neuroscience.

OBJECTIVE

Here, we delineated the cortical origin of TEP by spatially and temporally localizing successive TEP components, and modulating them with transcranial direct current stimulation (tDCS) to investigate cortical reactivity elicited by single-pulse TMS and its causal relationship with cortical excitability.

METHODS

We recruited 18 healthy participants in a double-blind, cross-over, sham-controlled design. We collected motor-evoked potentials (MEPs) and TEPs elicited by suprathreshold single-pulse TMS targeting the left primary motor cortex (M1). To causally test cortical and corticospinal excitability, we applied tDCS to the left M1.

RESULTS

We found that the earliest TEP component (P25) was localized to the left M1. The following TEP components (N45 and P60) were largely localized to the primary somatosensory cortex, which may reflect afferent input by hand-muscle twitches. The later TEP components (N100, P180, and N280) were largely localized to the auditory cortex. As hypothesized, tDCS selectively modulated cortical and corticospinal excitability by modulating the pre-stimulus mu-rhythm oscillatory power.

CONCLUSION

Together, our findings provide causal evidence that the early TEP components reflect cortical reactivity to TMS.

β Decay of ^{61}V and its Role in Cooling Accreted Neutron Star Crusts

The interpretation of observations of cooling neutron star crusts in quasipersistent x-ray transients is affected by predictions of the strength of neutrino cooling via crust Urca processes. The strength of crust Urca neutrino cooling depends sensitively on the electron-capture and β-decay ground-state-to-ground-state transition strengths of neutron-rich rare isotopes. Nuclei with a mass number of A=61 are predicted to be among the most abundant in accreted crusts, and the last remaining experimentally undetermined ground-state-to-ground-state transition strength was the β decay of ^{61}V. This Letter reports the first experimental determination of this transition strength, a ground-state branching of 8.1_{-3.1}^{+4.0}%, corresponding to a log ft value of 5.5_{-0.2}^{+0.2}. This result was achieved through the measurement of the β-delayed γ rays using the total absorption spectrometer SuN and the measurement of the β-delayed neutron branch using the neutron long counter system NERO at the National Superconducting Cyclotron Laboratory at Michigan State University. This method helps to mitigate the impact of the pandemonium effect in extremely neutron-rich nuclei on experimental results. The result implies that A=61 nuclei do not provide the strongest cooling in accreted neutron star crusts as expected by some predictions, but that their cooling is still larger compared to most other mass numbers. Only nuclei with mass numbers 31, 33, and 55 are predicted to be cooling more strongly. However, the theoretical predictions for the transition strengths of these nuclei are not consistently accurate enough to draw conclusions on crust cooling. With the experimental approach developed in this work, all relevant transitions are within reach to be studied in the future.

Calretinin-Positive Mucosal Innervation (C-mi) as a Potential Biomarker to Predict Fibrosis in Crohn’s Disease (CD): A Pilot Study

Introduction/Objective

There is no reliable biomarker to predict the degree of fibrosis in CD. Quantification of C-mi has been used as a surrogate for enteric neural structures in Hirschsprung disease. The quantity of C-mi at the proximal margin may correlate with the degree of fibrosis in resected CD.

Methods

Ileocolonic resection cases for 20 CD and 3 trauma (control) were retrieved. Cases with severe mucosal inflammation at the margins were excluded. The proximal and distal margin sections were subjected to calretinin immunohistochemistry. Random mucosal images were captured from scanned slides (x200, JPEG), submucosa was edited out, and C-mi was calculated by image processing and analysis. rC-mi was defined as the mean C-mi of proximal margin normalized by that of distal margin. Cases with rC-mi less than the mean rC-mi + 2 SD of the controls were excluded. The maximum thicknesses of submucosa and muscularis propria were measured at the most stenotic site, microscopically. Pearson’s correlation test and Student’s t-test were performed to correlate the parameters and compare the means, respectively.

Results

A total of 216 images were captured (mean 9.3 images per case; range 7 to 10). The mean rC-mi of CD (1.26) was greater than the controls (mean 0.43) (p&lt;0.05). The mean rC-mi + 2 SD of the control group was 0.91, thus 2 CD cases were excluded from final analysis. The rC-mi of CD showed an inverse relationship with maximum submucosal thickness (mean 3.4 mm, range 0.2 to 5.9) at the site of stenosis (r=-0.47; p&lt;0.05), but not with muscularis propria.

Conclusion

The rC-mi of CD was inversely correlated with submucosal fibrosis. Altered stromal integrity, impaired intercellular signaling, progressive reduction and loss of telocytes induced by submucosal fibrosis may reduce the regenerative capacity of enteric neural structures in CD. Therefore, a decreasing trend in rC-mi may predict fibrosis progression in CD.

Progesterone modulates theta oscillations in the frontal-parietal network

The neuroactive metabolites of the steroid hormones progesterone (P4) and testosterone (T) are GABAergic modulators that influence cognition, yet, the specific effect of P4 and T on brain network activity remains poorly understood. Here, we investigated if a fundamental oscillatory network activity pattern, often related to cognitive control, frontal midline theta (FMT) oscillations, are modulated by steroids hormones, P4 and T. We measured the concentration of P4 and T using salivary enzyme immunoassay and FMT oscillations using high-density electroencephalography (EEG) during eyes-open resting-state in 55 healthy women and men. Electrical brain activity was analyzed using Fourier analysis, aperiodic signal fitting, and beamformer source localization. Steroid hormone concentrations and biological sex were used as predictors for scalp and source-estimated amplitude of theta oscillations. Elevated concentrations of P4 predicted increased amplitude of FMT oscillations across both sexes, and no relationship was found with T. The positive correlation with P4 was specific to the frontal midline electrodes and survived correction for the background aperiodic signal of the brain. Using source localization, FMT oscillations were localized to the frontal-parietal network (FPN). Additionally, theta amplitude within the FPN, but not the default mode network, positively correlated with P4 concentration. Our results suggest that P4 concentration modulates brain activity via upregulation of theta oscillations in the FPN.

Exploring the relationship between geomagnetic activity and human heart rate variability

PURPOSE

Both geomagnetic and solar activity fluctuate over time and have been proposed to affect human physiology. Heart rate variability (HRV) has substantial health implications regarding the ability to adapt to stressors and has been shown to be altered in many cardiovascular and neurological disorders. Intriguingly, previous work found significant, strong correlations between HRV and geomagnetic/solar activity. The purpose of this study to replicate these findings. We simultaneously measured HRV during a 30-day period.

METHODS

We recruited 20 healthy participants and measured their HRV for a 30-day period. We also collected geomagnetic and solar activity during this period for investigating their relationship with the HRV data.

RESULTS

In agreement with previous work, we found several significant correlations between short-term HRV and geophysical time-series. However, after correction for autocorrelation, which is inherent in time-series, the only significant results were an increase in very low frequency during higher local geomagnetic activity and a geomagnetic anticipatory decrease in heart rate a day before the higher global geomagnetic activity. Both correlations were very low. The loss of most significant effects after this correction suggests that previous findings may be a result of autocorrelation. A further note of caution is required since our and the previous studies in the field do not correct for multiple comparisons given the exploratory analysis strategy.

CONCLUSION

We thus conclude that the effects of geomagnetic and solar activity are (if present) most likely of very small effect size and we question the validity of the previous studies given the methodological concerns we have uncovered with our work.

Axion Dark Matter Search around 6.7 μeV

An axion dark matter search with the CAPP-8TB haloscope is reported. Our results are sensitive to axion-photon coupling g_{aγγ} down to the QCD axion band over the axion mass range between 6.62 and 6.82  μeV at a 90% confidence level, which is the most sensitive result in the mass range to date.

Transition Zone in Total Colonic Aganglionosis and Colorectal Hirschsprung's Disease Shows a Similar Trend of Mucosal Innervation: Image Processing and Analysis Study

The aganglionic segment of bowel in Hirschsprung's disease (HD) varies in length. It is not clear whether total colonic aganglionosis (TCA) merely represents a long form of HD or a different phenotype of the disease. Animal model studies suggest that TCA may have a longer transition zone (TZ) than conventional colorectal HD. We compared mucosal innervation of TZ in 2 TCA cases and 10 conventional colorectal HD cases by quantifying calretinin-positive mucosal nerve fibers using image processing and analysis. One TCA was associated with esophageal atresia-tracheoesophageal fistula, the other with trisomy 21. The gradients of calretinin-stained pixel count increase per distance from the beginning of TZ (slope) for TCA were not significantly different from those for the conventional HD group. Given this observation, it is speculated that the length of TZ in TCA may fall within the range of and may not be much longer than conventional colorectal HD.