Deficits in Prediction Ability Trigger Asymmetries in Behavior and Internal Representation

Predictive coding is an emerging theoretical framework for explaining human perception and behavior. The proposed underlying mechanism is that signals encoding sensory information are integrated with signals representing the brain's prior prediction. Imbalance or aberrant precision of the two signals has been suggested as a potential cause for developmental disorders. Computational models may help to understand how such aberrant tendencies in prediction affect development and behavior. In this study, we used a computational approach to test the hypothesis that parametric modifications of prediction ability generate a spectrum of network representations that might reflect the spectrum from typical development to potential disorders. Specifically, we trained recurrent neural networks to draw simple figure trajectories, and found that altering reliance on sensory and prior signals during learning affected the networks' performance and the emergent internal representation. Specifically, both overly strong or weak reliance on predictions impaired network representations, but drawing performance did not always reflect this impairment. Thus, aberrant predictive coding causes asymmetries in behavioral output and internal representations. We discuss the findings in the context of autism spectrum disorder, where we hypothesize that too weak or too strong a reliance on predictions may be the cause of the large diversity of symptoms associated with this disorder.

Search for Electron Antineutrino Appearance in a Long-Baseline Muon Antineutrino Beam

Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and antineutrino appearance also finds no discrepancy between data and PMNS predictions.

Predictive learning: its key role in early cognitive development

What is a fundamental ability for cognitive development? Although many researchers have been addressing this question, no shared understanding has been acquired yet. We propose that predictive learning of sensorimotor signals plays a key role in early cognitive development. The human brain is known to represent sensorimotor signals in a predictive manner, i.e. it attempts to minimize prediction error between incoming sensory signals and top–down prediction. We extend this view and suggest that two mechanisms for minimizing prediction error lead to the development of cognitive abilities during early infancy. The first mechanism is to update an immature predictor. The predictor must be trained through sensorimotor experiences because it does not inherently have prediction ability. The second mechanism is to execute an action anticipated by the predictor. Interacting with other individuals often increases prediction error, which can be minimized by executing one's own action corresponding to others’ action. Our experiments using robotic systems replicated developmental dynamics observed in infants. The capabilities of self–other cognition and goal-directed action were acquired based on the first mechanism, whereas imitation and prosocial behaviours emerged based on the second mechanism. Our theory further provides a potential mechanism for autism spectrum condition. Atypical tolerance for prediction error is hypothesized to be a cause of perceptual and social difficulties.

This article is part of the theme issue ‘From social brains to social robots: applying neurocognitive insights to human–robot interaction’.

Morphological lymphocytic reaction, patient prognosis and PD-1 expression after surgical resection for oesophageal cancer

BACKGROUND

Immune checkpoint inhibitors, such as antibody against programmed cell death protein (PD-1), have demonstrated antitumour effects in patients with malignancies, including oesophageal cancer. A lymphocytic reaction observed by pathological examination is a manifestation of the host immune response to tumour cells. It was hypothesized that a stronger lymphocytic reaction to tumours might be associated with favourable prognosis in oesophageal cancer.

METHODS

Using a database of resected oesophageal cancers, four morphological components of lymphocytic reactions (peritumoral, intranest, lymphoid and stromal) to tumours were evaluated in relation to clinical outcome, PD-1 expression by immunohistochemistry and total lymphocyte count in blood.

RESULTS

Resected oesophageal cancer specimens from 436 patients were included in the study. Among the four morphological components, only peritumoral reaction was associated with patient prognosis (multivariable P for trend <0·001); patients with a higher peritumoral reaction had significantly longer overall survival than those with a lower reaction (multivariable hazard ratio 0·48, 95 per cent c.i. 0·34 to 0·67). The prognostic effect of peritumoral reaction was not significantly modified by other clinical variables (all P for interaction >0·050). Peritumoral reaction was associated with total lymphocyte count in the blood (P < 0·001), supporting the relationship between local immune response and systemic immune competence. In addition, higher morphological peritumoral reaction was associated with high PD-1 expression on lymphocytes in tumours (P = 0·034).

CONCLUSION

These findings should help to improve risk-adapted therapeutic strategies and help stratify patients in the future clinical setting of immunotherapy for oesophageal cancer.

74 Analysis of chromosomal abnormality of bovine IVF embryos based on next-generation sequencing

It has been suggested that bovine IVF embryos have a higher frequency of occurrence of chromosomal abnormalities than invivo-fertilised embryos, which may explain low pregnancy success, but the details have not been clarified (Yao et al. 2018 Sci. Rep. 8, 7460). In this study, chromosomal aneuploidy in blastocysts of bovine IVF and invivo-fertilised was analysed by copy number variations (CNVs) based on next-generation sequencing. The IVF bovine embryos were cultured in well of-the-well culture dishes (LinKID micro25: Dai Nippon Printing) containing 125µL of CR1aa supplemented with 5% calf serum at 38.5°C in 5% O2 and 5% CO2 for 8 days after insemination. Invitro development of embryos was monitored using time-lapse cinematography (Sugimura et al. 2010 Biol. Reprod. 83, 970-78). Invivo embryos were produced by collection of a superstimulated Japanese Black cow. Embryos that reached the blastocyst stage were divided into inner cell mass (ICM) and trophectoderm (TE) fractions by a micromanipulator with a blade. The TE and ICM samples were biopsied individually from 10 IVF and 4 invivo-derived embryos, and extracted DNA was amplified using the SurePlex DNA amplification System (Illumina). The whole-genome amplified DNA libraries were sequenced using MiSeq (Illumina). The sequencing reads were mapped onto the Bos taurus reference genome ARS-UCD1.2, obtained from the National Center for Biotechnology Information. In all 29 autosomal chromosomes and the X chromosome, CNV analysis was performed by CNV-seq (Xie and Tammi 2009 BMC Bioinformatics 10, 80). Male or female Japanese Black cattle DNA sequence was used for the reference genome. The parameter of CNV-seq was run with P-value=0.001, log2=0.6, and window size=1M. Four IVF embryos showed chromosomal duplications or deletions in either ICM- or TE-cell samples (4/10, 40%). The CNV loci between ICM and TE cells were relatively similar in each embryo. One of them was a code 1-expanded blastocyst with normal cleavage. Interestingly, CNV was not identified in another code 1-expanded blastocyst that underwent direct cleavage from 1 cell to 3 or more cells. In invivo embryos, only one embryo had a CNV (1/4, 25%). Observed CNVs in both IVF and invivo embryos were segmental duplication or deletion in each chromosome. Hence, to improve pregnancy success in bovine IVF embryos, cytogenetic evaluation may be useful for quality evaluation of embryos that are prone to chromosomal abnormalities, as well as morphological scoring.

Acute effects of difference in glucose intake on arterial stiffness in healthy subjects

BACKGROUND

Post-prandial hyperglycemia is associated with higher cardiovascular risk, which causes arterial stiffening and impaired function. Although post-prandial increases in blood glucose are proportional to the level of intake, the acute effects of different glucose intakes on arterial stiffness have not been fully characterized. The present study aimed to determine the acute effects of differences in glucose intake on arterial stiffness.

METHODS

Six healthy middle-aged and elderly individuals (mean age, 60.0 ± 12.1 years) were orally administered 15, 20, and 25 g of glucose on separate days in a randomized, controlled, cross-over fashion. Brachial-ankle pulse wave velocity, heart-brachial pulse wave velocity, cardio-ankle vascular index, brachial and ankle blood pressure, heart rate, and blood glucose and serum insulin concentrations before and 30, 60, and 90 min after glucose ingestion were measured.

RESULTS

Compared to baseline, brachial-ankle pulse wave velocity was higher at 30, 60 and 90 min after ingestion of 25 g glucose, and higher at 90 min after ingestion of 20 g glucose, but at no time points after ingestion of 15 g. Cardio-ankle vascular index was higher at 60 min than at baseline after ingestion of 25 g glucose, but not after ingestion of 15 or 20 g.

CONCLUSIONS

These results suggest that brachial-ankle pulse wave velocity and cardio-ankle vascular index is affected by the quantity of glucose ingested. Proposed presently is that glucose intake should be reduced at each meal to avoid increases in brachial-ankle pulse wave velocity and cardio-ankle vascular index during acute hyperglycemia.

Effectiveness of nanoparticle albumin-bound paclitaxel plus carboplatin in non-small lung cancer patients with malignant pleural effusion

Malignant pleural effusion (MPE) is a common complication occurring in cancer patients, and its management affects the prognosis of these patients. Preclinical and clinical studies have reported that treatment with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus carboplatin (CBDCA) is effective against intraperitoneal malignant tumors. To investigate the effectiveness of nab-paclitaxel plus CBDCA therapy for MPEs arising in patients with non-small cell lung cancer (NSCLC), we retrospectively analyzed the clinicopathological characteristics of 40 patients with stage IIIb or IV NSCLC who were treated with nab-paclitaxel plus CBDCA from 2013 to 2016. Out of 26 patients with MPEs who were treated with nab-paclitaxel plus CBDCA in this study, 21 patients (80.8%) had effective responses in MPEs; 6 of 21 patients exhibited complete responses (23.1%) and 15 of 21 had partial responses (57.7%). Kaplan-Meier survival curves and log-rank tests to evaluate the effectiveness of nab-paclitaxel plus CBDCA therapy against MPEs showed longer median progression-free survival (323 days vs. 26 days; p=0.009) and overall survival (not reached vs. 199 days; p=0.047) in patients with complete responses compared with those who achieved no response. There were no statistical differences between therapeutic effects on MPEs and those on systemic lesions. Nab-paclitaxel plus CBDCA therapy may be a preferred therapeutic option for patients with NSCLC who experience MPEs, and its effectiveness in treatment of MPEs may need to be evaluated separately from its therapeutic responses in systemic lesions.

Lesser suppression of response to bright visual stimuli and visual abnormality in children with autism spectrum disorder: a magnetoencephalographic study

BACKGROUND

Visual abnormality is a common sensory impairment in autism spectrum disorder (ASD), which may cause behavioral problems. However, only a few studies exist on the neural features corresponding to the visual symptoms in ASD. The purpose of this study was to investigate the relationship between cortical responses to visual stimuli and visual abnormality to examine the neurophysiological mechanisms of the visual abnormality in ASD.

METHODS

Twenty-two high-functioning children with ASD (10.95 ± 2.01 years old) and 23 age-matched typically developing (TD) children (10.13 ± 2.80 years old) participated in this study. We measured the cortical responses (i.e., activated intensity and attenuation ratio) elicited by the Original visual image and other two types of bright images (the Dot noise or Blind image, which includes overlapped particles onto the Original image or the enhanced-brightness version of the Original image, respectively) using magnetoencephalography.

RESULTS

The severity of visual abnormalities was significantly associated with behavioral problems in children with ASD. In addition, we found the increased cortical activation in response to the Original image in the left supramarginal gyrus (SMG) and middle temporal gyrus in children with ASD. However, there were no inter-group differences in the primary visual and medial orbitofrontal cortices. Furthermore, when we compared cortical responses according to the type of images, children with ASD showed lesser attenuation of the activated intensities than children with TD in response to the bright images compared with the Original image in the right SMG. These attenuation ratios (Dot noise/Original and Blind/Original) were also associated with the severity of visual abnormalities.

CONCLUSIONS

Our results show that dysfunction of stimulus-driven neural suppression plays a crucial role in the neural mechanism of visual abnormality in children with ASD. To the best of our knowledge, this is the first magnetoencephalography study to demonstrate the association between the severity of visual abnormality and lower attenuation ratios in children with ASD. Our results contribute to the knowledge of the mechanisms underlying visual abnormality in children with ASD, and may therefore lead to more effective diagnosis and earlier intervention.