40 Hz Steady-State Response in Human Auditory Cortex Is Shaped by GABAergic Neuronal Inhibition

The 40 Hz auditory steady-state response (ASSR), an oscillatory brain response to periodically modulated auditory stimuli, is a promising, non-invasive physiological biomarker for schizophrenia and related neuropsychiatric disorders. The 40 Hz ASSR might be amplified by synaptic interactions in cortical circuits, which are, in turn, disturbed in neuropsychiatric disorders. Here, we tested whether the 40 Hz ASSR in human auditory cortex depends on two key synaptic components of neuronal interactions within cortical circuits: excitation via N-methyl-aspartate glutamate (NMDA) receptors and inhibition via gamma-amino-butyric acid (GABA) receptors. We combined magnetoencephalography (MEG) recordings with placebo-controlled, low-dose pharmacological interventions in the same healthy human participants (13 males, 7 females). All participants exhibited a robust 40 Hz ASSR in auditory cortices, especially in the right hemisphere, under placebo. The GABAA receptor-agonist lorazepam increased the amplitude of the 40 Hz ASSR, while no effect was detectable under the NMDA-blocker memantine. Our findings indicate that the 40 Hz ASSR in auditory cortex involves synaptic (and likely intracortical) inhibition via the GABA-A receptor, thus highlighting its utility as a mechanistic signature of cortical circuit dysfunctions involving GABAergic inhibition.Significance statement The 40 Hz auditory steady-state response is a candidate non-invasive biomarker for schizophrenia and related neuropsychiatric disorders. Yet, the understanding of the synaptic basis of this neurophysiological signature in humans has remained incomplete. We combined magnetoencephalography (MEG) recordings with placebo-controlled pharmacological interventions in healthy human subjects to test the modulation of the 40 Hz ASSR in auditory cortex by two synaptic components that have been implicated in the generation of neuronal oscillations in cortical microcircuits: glutamate N-methyl-aspartate glutamate (NMDA) receptors and gamma-amino-butyric acid (GABA) -A receptors. Boosting GABAergic transmission, but not blocking NMDA-receptors, increased the amplitude of this ASSR. Thus, GABAergic inhibition modulates 40 Hz steady-state responses in auditory cortex.

Increased neural variability in adolescents with ADHD symptomatology: Evidence from a single-trial EEG study

Increased intrasubject variability of reaction time (RT) refers to inconsistency in an individual's speed of responding to a task. This increased variability has been suggested as a fundamental feature of attention deficit hyperactivity disorder (ADHD), however, its neural sources are still unclear. In this study, we aimed to examine whether such inconsistency at the behavioral level would be accompanied by inconsistency at the neural level; and whether different types of neural and behavioral variability would be related to ADHD symptomatology. We recorded electroencephalogram (EEG) data from 62 adolescents, who were part of a prospective longitudinal study on the development of ADHD. We examined trial-by-trial neural variability in response to visual stimuli in two cognitive tasks. Adolescents with high ADHD symptomatology exhibited an increased neural variability before the presentation of the stimulus, but when presented with a visual stimulus, this variability decreased to a level that was similar to that exhibited by participants with low ADHD symptomatology. In contrast with our prediction, neural variability was unrelated to the magnitude of behavioral variability. Our findings suggest that adolescents with higher symptoms are characterized by increased neural variability before the stimulation, which might reflect a difficulty in alertness to the forthcoming stimulus; but this increased neural variability does not seem to account for their RT variability.

Ustekinumab during pregnancy in patients with inflammatory bowel disease: a prospective multicentre cohort study

BACKGROUND

Women with inflammatory bowel diseases (IBD) often receive biologics to maintain remission during pregnancy.

AIMS

To assess maternal and neonatal outcomes in patients with IBD treated with ustekinumab (UST) during pregnancy METHODS: In a multicentre, prospective cohort study, we recruited women with IBD treated with UST during pregnancy between 2019 and 2021. Outcomes were compared among patients treated with UST, anti-tumour necrosis factor α, (anti-TNF) and non-UST, non-anti-TNF therapies. UST-treated patients were matched 1:2 to controls according to age, body mass index and parity. Newborns were followed up to 12 months.

RESULTS

We recruited 129 pregnant patients: UST 27; anti-TNF 52; non-UST, non-anti-TNF 50 (thiopurine or mesalazine 30, no therapy 20); Crohn's disease 25 (96.9%). Overall, pregnancy, neonatal and newborn outcomes were satisfactory, with no significant differences among patients treated with UST, anti-TNF and non-UST non-anti-TNF agents for obstetrical maternal complications [UST 3 (11.5%), anti TNF 12 (23.1%), non UST, non-anti-TNF 4 (8.2%), p = 0.095], pre-term delivery [1 (4.3%), 9 (18.4%), 4 (5.7%), p = 0.133], low birth weight [1 (4.2%), 5 (10.2%), 4 (8.3%), p = 0.679], or first year newborn hospitalisation [2 (9.1%), 4 (8.2%), 3 (6.1%), p = 0.885].

CONCLUSION

Pregnant patients with IBD treated with UST demonstrated favourable pregnancy and neonatal outcomes that were comparable with those in patients treated with anti-TNF or other therapy. Data are reassuring for patients with IBD and their physicians when considering UST during pregnancy.

Home-quarantine during the initial Covid-19 outbreak in Israel: parent perceived impact on children with ASD

Background

Studies have reported that Covid-19 home-quarantine periods have had mostly negative psychological impact on children with ASD and their families. Here we examined parent perceived impact of a 6-week quarantine period imposed in Israel at the beginning of the Covid-19 outbreak, in mid-March 2020.

Methods

An anonymous online questionnaire was completed by parents of 268 children with ASD. Parents rated deterioration/improvement in their child's behaviors, abilities, mood, sleep, and anxiety along with changes in their own mood, sleep, parenting skills, and family relationships. We performed t-tests and ANOVA analyses to assess the significance of perceived impact on each domain and potential differences in the impact across families with children of different ages, genders, and levels of required support as well as families that experienced different magnitudes of economic hardships.

Results

Parents reported significant deterioration in their mood and sleep along with significant improvements in relationships with their spouse and child with ASD, and in their parenting skills. Parents also reported significant increases in the severity of tantrums, anxiety, and restricted and repetitive behavior symptoms along with significant improvements in social and communication abilities of their child with ASD. Ratings were significantly lower in families of ASD children who regularly require more support and in families that experienced economic hardships.

Conclusions

While periods of home-quarantine create numerous hardships for families of children with ASD, they may also offer an opportunity for improving parenting skills, family relationships, and children's social communication abilities with potential relevance for improving remote services.

Correlation between the latitudinal profile of the 7Be air concentration and the Hadley cell extent in the Southern Hemisphere

The cosmogenic radionuclide ⁷Be is one of the best tracers for aerosol transport since its half-life of 53 days is in the time scale of many atmospheric circulation phenomena. In this work, we analyze a 12-years-long daily time-series for the airborne ⁷Be concentration for nine air filtering stations in the Southern Hemisphere or close to it. The observed latitudinal distribution of ⁷Be concentration, with its maximum at the southern subtropical high-pressure belt, is similar to the one in the Northern Hemisphere. A good time correlation was found between the 7°-shift of the ⁷Be concentration latitudinal distribution and the seasonal displacement of the extent of the Hadley cell. This is consistent with tropopause folding events, mostly occurring in spring, being the main contribution for the injection of stratospheric ⁷Be into the descending branch of the Hadley cell.

Altered slow-wave sleep activity in children with rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation syndrome

STUDY OBJECTIVES

Rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation (ROHHAD) is a rare condition. Little is known about sleep/wake and slow-wave activity in this condition, although the central hypothalamic dysfunction associated with autonomic dysregulation would make the occurrence of SWA deregulation most likely.

METHODS

Two children with clinical presentation of ROHHAD syndrome were evaluated, diagnosed, and treated. Their polysomnographic studies were compared with 4 matched children with obstructive sleep apnea and 6 controls.

RESULTS

Children that were clinically diagnosed with ROHHAD exhibited significantly weaker slow-wave activity power and shallower slow-wave activity slopes during the first 2 sleep cycles compared with children with obstructive sleep apnea or controls.

CONCLUSIONS

This study shows that children with ROHHAD have suppressed slow-wave activity, possibly because of hypothalamic dysregulation that may contribute to their rapid-onset obesity and excessive daytime sleepiness.

Supernova-Produced ^{53}Mn on Earth

For the time period from 1.5 to 4 Myr before the present we found in deep ocean ferromanganese crusts a ^{53}Mn excess concentration in terms of ^{53}Mn/Mn of about 4×10^{-14} over that expected for cosmogenic production. We conclude that this ^{53}Mn is of supernova origin because it is detected in the same time window, about 2.5 Myr ago, where ^{60}Fe has been found earlier. This overabundance confirms the supernova origin of that ^{60}Fe. For the first time, supernova-formed ^{53}Mn has been detected and it is the second positively identified radioisotope from the same supernova. The ratio ^{53}Mn/^{60}Fe of about 14 is consistent with that expected for a SN with a 11-25  M_{⊙} progenitor mass and solar metallicity.

Reduced sleep pressure in young children with autism

Study Objectives

Sleep disturbances and insomnia are highly prevalent in children with Autism Spectrum Disorder (ASD). Sleep homeostasis, a fundamental mechanism of sleep regulation that generates pressure to sleep as a function of wakefulness, has not been studied in children with ASD so far, and its potential contribution to their sleep disturbances remains unknown. Here, we examined whether slow-wave activity (SWA), a measure that is indicative of sleep pressure, differs in children with ASD.

Methods

In this case-control study, we compared overnight electroencephalogram (EEG) recordings that were performed during Polysomnography (PSG) evaluations of 29 children with ASD and 23 typically developing children.

Results

Children with ASD exhibited significantly weaker SWA power, shallower SWA slopes, and a decreased proportion of slow-wave sleep in comparison to controls. This difference was largest during the first 2 hours following sleep onset and decreased gradually thereafter. Furthermore, SWA power of children with ASD was significantly negatively correlated with the time of their sleep onset in the lab and at home, as reported by parents.

Conclusions

These results suggest that children with ASD may have a dysregulation of sleep homeostasis that is manifested in reduced sleep pressure. The extent of this dysregulation in individual children was apparent in the amplitude of their SWA power, which was indicative of the severity of their individual sleep disturbances. We, therefore, suggest that disrupted homeostatic sleep regulation may contribute to sleep disturbances in children with ASD.

The Relationship between Trial-by-Trial Variability and Oscillations of Cortical Population Activity

Neural activity fluctuates over time, creating considerable variability across trials. This trial-by-trial neural variability is dramatically reduced (“quenched”) after the presentation of sensory stimuli. Likewise, the power of neural oscillations, primarily in the alpha-beta band, is also reduced after stimulus onset. Despite their similarity, these phenomena have so far been studied and discussed independently. We hypothesized that the two phenomena are tightly coupled in electrophysiological recordings of large cortical neural populations. To test this, we examined magnetoencephalography (MEG) recordings of healthy subjects viewing repeated presentations of a visual stimulus. The timing, amplitude, and spatial topography of variability-quenching and power-suppression were remarkably similar. Neural variability quenching was eliminated by excluding the alpha-beta band from the recordings, but not by excluding other frequency-bands. Moreover, individual magnitudes of alpha-beta band-power explained 86% of between-subject differences in variability quenching. An alternative mechanism that may generate variability quenching is increased phase alignment across trials. However, changes in inter-trial-phase-coherence (ITPC) exhibited distinct timing and no correlations with the magnitude of variability quenching in individual participants. These results reveal that neural variability quenching is tightly coupled with stimulus-induced changes in the power of alpha-beta band oscillations, associating two phenomena that have so far been studied in isolation.

Neural Variability Quenching Predicts Individual Perceptual Abilities

Neural activity during repeated presentations of a sensory stimulus exhibits considerable trial-by-trial variability. Previous studies have reported that trial-by-trial neural variability is reduced (quenched) by the presentation of a stimulus. However, the functional significance and behavioral relevance of variability quenching and the potential physiological mechanisms that may drive it have been studied only rarely. Here, we recorded neural activity with EEG as subjects performed a two-interval forced-choice contrast discrimination task. Trial-by-trial neural variability was quenched by ∼40% after the presentation of the stimulus relative to the variability apparent before stimulus presentation, yet there were large differences in the magnitude of variability quenching across subjects. Individual magnitudes of quenching predicted individual discrimination capabilities such that subjects who exhibited larger quenching had smaller contrast discrimination thresholds and steeper psychometric function slopes. Furthermore, the magnitude of variability quenching was strongly correlated with a reduction in broadband EEG power after stimulus presentation. Our results suggest that neural variability quenching is achieved by reducing the amplitude of broadband neural oscillations after sensory input, which yields relatively more reproducible cortical activity across trials and enables superior perceptual abilities in individuals who quench more.

SIGNIFICANCE STATEMENT

Variability quenching is a phenomenon in which neural variability across trials is reduced by the presentation of a stimulus. Although this phenomenon has been reported across a variety of animal and human studies, its functional significance and behavioral relevance have been examined only rarely. Here, we report novel empirical evidence from humans revealing that variability quenching differs dramatically across individual subjects and explains to a certain degree why some individuals exhibit better perceptual abilities than others. In addition, we found a strong relationship between variability quenching and suppression of broadband neural oscillations. Together, our results reveal the importance of reproducible cortical activity for enabling better perceptual abilities and suggest a potential underlying mechanism that may explain why variability quenching occurs.

Characterization and identification of microbial communities in bovine necrotic vulvovaginitis

Bovine necrotic vulvovaginitis (BNVV) is a severe and potentially fatal disease of post-partum cows that emerged in Israel after large dairy herds were merged. While post-partum cows are commonly affected by mild vulvovaginitis (BVV), in BNVV these benign mucosal abrasions develop into progressive deep necrotic lesions leading to sepsis and death if untreated. The etiology of BNVV is still unknown and a single pathogenic agent has not been found. We hypothesized that BNVV is a polymicrobial disease where the normally benign vaginal microbiome is remodeled and affects the local immune response. To this end, we compared the histopathological changes and the microbial communities using 16S rDNA metagenetic technique in biopsies taken from vaginal lesions in post-partum cows affected by BVV and BNVV. The hallmark of BNVV was the formation of complex polymicrobial communities in the submucosal fascia and abrogation of neutrophil recruitment in these lesions. Additionally, there was a marked difference in the composition of bacterial communities in the BNVV lesions in comparison to the benign BVV lesions. This difference was characterized by the abundance of Bacteroidetes and lower total community membership in BNVV. Indicator taxa for BNVV were Parvimonas, Porphyromonas, unclassified Veillonellaceae, Mycoplasma and Bacteroidetes, whereas unclassified Clostridiales was an indicator for BVV. The results support a polymicrobial etiology for BNVV.

Increased ongoing neural variability in ADHD

Attention Deficit Hyperactivity Disorder (ADHD) has been described as a disorder where frequent lapses of attention impair the ability of an individual to focus/attend in a sustained manner, thereby generating abnormally large intra-individual behavioral variability across trials. Indeed, increased reaction time (RT) variability is a fundamental behavioral characteristic of individuals with ADHD found across a large number of cognitive tasks. But what is the underlying neurophysiology that might generate such behavioral instability? Here, we examined trial-by-trial EEG response variability to visual and auditory stimuli while subjects' attention was diverted to an unrelated task at the fixation cross. Comparisons between adult ADHD and control participants revealed that neural response variability was significantly larger in the ADHD group as compared with the control group in both sensory modalities. Importantly, larger trial-by-trial variability in ADHD was apparent before and after stimulus presentation as well as in trials where the stimulus was omitted, suggesting that ongoing (rather than stimulus-evoked) neural activity is continuously more variable (noisier) in ADHD. While the patho-physiological mechanisms causing this increased neural variability remain unknown, they appear to act continuously rather than being tied to a specific sensory or cognitive process.

The role of positive feedback loops involving anti-dsDNA and anti-anti-dsDNA antibodies in autoimmune glomerulonephritis

Autoimmune glomerulonephritis (GN) is a potentially life-threatening renal inflammation occurring in a significant percentage of systemic lupus erythematosus (SLE) patients. It has been suggested that GN develops and persists due to a positive feedback loop, in which inflammation is promoted by the deposition in the kidney of immune complexes (IC) containing double-stranded DNA (dsDNA) and autoantibodies specific to it, leading to cellular death, additional release to circulation of dsDNA, continuous activation of dsDNA-specific autoreactive B cells and further formation of IC. We have recently presented a generic model exploring the dynamics of IC-mediated autoimmune inflammatory diseases, applicable also to GN. Here we extend this model by incorporating into it a specific B cell response targeting anti-dsDNA antibodies-a phenomenon whose occurrence in SLE patients is well-supported empirically. We show that this model retains the main results found for the original model studied, particularly with regard to the sensitivity of the steady state properties to changes in parameter values, while capturing some disease-specific observations found in GN patients which are unaccountable using our previous model. In particular, the extended model explains the findings that this inflammation can be ameliorated by treatment without lowering the level of anti-dsDNA antibodies. Moreover, it can account for the inverse oscillations of anti-dsDNA and anti-anti-dsDNA antibodies, previously reported in lupus patients. Finally, it can be used to suggest a possible explanation to the so-called regulatory role of TLR9, found in murine models of lupus; i.e., the fact that the knockdown of this DNA-sensing receptor leads, as expected, to a decrease in the level of anti-dsDNA antibodies, but at the same time results in a counter-intuitive amplification of the autoreactive immune response and an exacerbated inflammation. Several predictions can be derived from the analysis of the presented model, allowing its experimental verification.

Iodine-129 in animal thyroids from Argentina

(129)I and (127)I concentrations in animal thyroids coming from several regions of Argentina were determined by accelerator mass spectrometry (AMS) and gas chromatography (GC), respectively. The measured (129)I/(127)I ratios, ranging from 3 × 10(-12) to 4 × 10(-10), are significantly lower than those typical for areas in the northern hemisphere (10(-10)-10(-7)). The (129)I concentrations show a clear dependence with latitude and season, which can be understood considering tropospheric circulation patterns, possible (129)I sources and regional precipitation rates.

Modeling immune complex-mediated autoimmune inflammation

A number of autoimmune diseases are thought to feature a particular type of self-sustaining inflammation, caused by the deposition of immune complexes (IC) in the inflamed tissue and a consequent activation of local effector cells. The persistence of this inflammation is due to a positive feedback loop, where autoantigen particles released as part of the tissue damage caused by the inflammation stimulate autoreactive B cells, leading to the formation of further immune complexes and their subsequent deposition. We present a mathematical model for the exploration of IC-mediated autoimmune inflammation and its clinical implications. We characterize the possible differences between normal individuals and those susceptible to such inflammation, and show that both random perturbations and bifurcations can lead to disease onset. Our model explains how defects in the mechanisms responsible for cellular debris clearance contribute to the development of disease, in agreement with empirical evidence. Moreover, we show that parameters governing the dynamics of immune complexes, such as their clearance rate, have an even stronger effect in determining the behavior of the system. We demonstrate the existence of hysteresis, implying that once IC-mediated autoimmune inflammation is triggered, its long-term suppression may be difficult to achieve. Our results can serve to guide the development of novel therapies to autoimmune diseases involving this type of inflammation.

Cattle immune response to botulinum type D toxoid: Results of a vaccination study

Cattle botulism is a food-borne intoxication caused by the ingestion of preformed botulinum neurotoxins (BoNT) of serotypes B, C, or D. Protection in cattle against botulinum intoxication is based on the presence of specific serum neutralizing antibodies upon exposure. Outbreaks in vaccinated cattle have raised concerns about vaccine quality and efficacy. To this end, three different immunization protocols and the effect of maternal anti-BoNT/D antibodies, at the priming dose, were analyzed in 2-month-old dairy calves. Based on previously determined protective anti-BoNT/D antibody levels analyzed in field outbreaks, the immune response to type D toxoids was analyzed using an in-house ELISA system. Here we show that using the current vaccination strategy of using a priming dose in 2-month-old calves followed by booster doses after 4 weeks and annually thereafter, did not result in continuous protective levels of anti-BoNT/D antibodies. As a result of this vaccination protocol, only 15-31% of cattle in parities 1-3 were protected at the time of the annual booster. Vaccination study in calves indicated that adding a 6-month booster dose to the current protocol resulted in continuous protective levels of anti-BoNT/D antibodies well above the cut-off protective levels. The presence of maternally derived anti-BoNT/D antibodies did not interfere with the immune response to toxoids that can be administered to 2-month-old calves.