Prevalence and Associated Factors of Pathological Internet Use and Online Risky Behaviors Among Japanese Elementary School Children.

BACKGROUND: Little is known about pathological Internet use (PIU) and online risky behaviors among elementary school children. We aimed to investigate the prevalence and factors associated with PIU and online risky behaviors. METHODS: A school-based cross-sectional study was conducted in Toyama, Japan in 2018. The study included 13,413 children in the 4th-6th grades (mean, 10.5 years old) from 110 elementary schools (61.1% of elementary schools in Toyama). We assessed PIU using Young's Diagnostic Questionnaire (YDQ) and risky behaviors. Poisson regression analysis was conducted. RESULTS: Totally, 13,092 children returned questionnaires (response rate 97.6%). The prevalence of PIU was 4.2% and that of each risky behavior was as follows: 21.6% for spending money online, 6.6% for uploading personal movies, 5.2% for interpersonal issues, and 2.4% for having met strangers. PIU was significantly associated with boys (prevalence ratio [PR] 1.26; 95% confidence interval [CI], 1.04-1.52), skipping breakfast (PR 1.43; 95% CI, 1.14-1.79), Internet time (for 2∼3 h, PR 3.49; 95% CI, 2.63-4.65; for 3∼4 h, PR 4.45; 95% CI, 3.27-6.06; and for ≥4 h, PR 8.25; 95% CI, 6.45-10.55), physical inactivity (PR 2.63; 95% CI, 2.00-3.47), late bedtime (PR 1.86; 95% CI, 1.45-2.39 for ≥11 p.m.), no rules at home (PR 1.22; 95% CI, 1.01-1.46), no child-parent interaction (PR 1.37; 95% CI, 1.06-1.77), and no close friends in real life (PR 1.69; 95% CI, 1.30-2.19). CONCLUSIONS: PIU and risky behaviors were not rare among the elementary school children. Besides unhealthy lifestyles, social and family environments were associated with PIU. Having child-parent interaction and helping children develop close friendships in real life are effective deterrents to PIU.

Association of short sleep duration and long media use with caries in school children.

BACKGROUND: Individual lifestyle factors are associated with dental caries in children. The aim of this study was to investigate comprehensively the association between dental caries in elementary school children and lifestyle factors of the children and their parents. METHODS: Children from five elementary schools in Takaoka city, Toyama Prefecture, Japan (1,699: 848 boys, 851 girls, age range 6-12 years) participated in a survey conducted in March 2016. Questions on socioeconomic status (SES) and lifestyle factors in the children and their parents were included. Children who received treatment for three or more dental caries were defined as having many caries. Logistic regression analysis was performed to evaluate whether these factors were associated with the number of caries. RESULTS: The percentage of children with many caries (≥3) was 38.4%. In univariate analysis, being in 5th or 6th grade, frequent snacking, short sleep duration, long hours of media use, paternal smoking, and parental skipping of breakfast were significantly associated with many caries. Lack of affluence was marginally significant. In multivariate analysis, the association of short hours of sleep and long hours of media use remained significant. The adjusted odds ratio (OR) for media use of 1-2 h and more than 2 h were 1.79 (95% confidence interval [CI]: 1.30-2.46) and 2.24 (95% CI: 1.61-3.11) respectively. The adjusted OR for less than 8 h of sleep was 1.49 (95% CI: 1.07-2.06). CONCLUSIONS: Long duration of media use and short duration of sleep were associated with dental caries. Establishing a healthy lifestyle is necessary for preventing dental caries in children.

Associations of socioeconomic status and lifestyle factors with dental neglect of elementary school children: the MEXT Super Shokuiku School Project.

BACKGROUND: Despite the fact that there are parents who do not take children with untreated dental caries to a dental clinic, few studies have been conducted to identify the responsible underlying social and family factors. The aim of this study was to investigate whether socioeconomic status and lifestyle factors are associated with dental neglect in elementary school children. METHODS: This study was conducted in 2016 with 1655 children from the Super Shokuiku School Project in Toyama. Using Breslow's seven health behaviors, the survey assessed: the grade, sex, and lifestyle of the children; parental internet and game use and lifestyle; socioeconomic status. The odds ratios (OR) and 95% confidence intervals (CIs) for having untreated dental caries were calculated using logistic regression analysis. RESULTS: Among the children participating, 152 (3.2%) had untreated dental caries. Among them, 53 (34.9%) had not been taken to a dental clinic despite the school dentist's advice. Dental neglect was significantly associated with children in higher grades (OR, 2.08; 95% CI, 1.14-3.78), father's Internet and game use ≥ 2 h/day (OR, 1.99; 95% CI, 1.02-3.88), not being affluent (OR, 2.78; 95% CI, 1.14-6.81), and non-engagement in afterschool activities (OR, 1.99; 95% CI, 1.10-3.62). CONCLUSIONS: Socioeconomic status was the strongest factor associated with dental neglect despite the fact that the children's medical expenses are paid in full by the National Health Insurance in Toyama, Japan. Future studies should investigate what factors prevent parents of non-affluent families from taking their children to dental clinics and how they can be socially supported to access adequate medical care.

Association between lifestyle, parental smoke, socioeconomic status, and academic performance in Japanese elementary school children: the Super Diet Education Project.

BACKGROUND: Health and education are closely linked. However, few studies have explored the correlates of children's academic performance in Japan. We aimed to investigate comprehensively the associations of low academic performance among school children with lifestyles, parental smoke, and socioeconomic status. METHODS: In 2016, children aged 6 to 13 years from the Super Diet Education School Project were surveyed using questionnaires. The survey explored the lifestyles and subjective academic performance of 1663 children and asked their parents about parental smoke and subjective socioeconomic status. Academic performance and socioeconomic status were divided into three levels. Then, we defined subjective academic performance in the lower two levels as low academic performance. The odds ratios (OR) were analyzed by logistic regression analysis. RESULTS: Among all participants, 299 (18.0%) children reported low academic performance. In general, low academic performance was significantly associated with late wakeup time (OR = 1.36 for 6:30 to < 7 a.m. and OR = 2.48 for ≥ 7 a.m.), screen time ≥ 2 h (OR = 1.35), studying at home < 1 h (OR = 1.82), paternal smoke (OR = 1.47), maternal smoke (OR = 1.87), and low socioeconomic status (OR = 1.48). Analyses stratified by grade showed stronger associations between academic performance and socioeconomic status in senior (OR = 1.62 for middle, OR = 1.52 for low in grades 4 to 6) than in junior children (OR = 1.15 for middle, OR = 1.38 for low in grades 1 to 3). CONCLUSIONS: Children's lifestyles, parental smoke, and socioeconomic status were significantly associated with low academic performance among Japanese children. Parents and health care providers should take these findings into consideration to prevent children from having low academic performance.

Prevalence of molar incisor hypomineralization and regional differences throughout Japan.

BACKGROUND: Molar incisor hypomineralization (MIH) frequently occurs in children worldwide. However, MIH prevalence throughout Japan has not yet been investigated. The purpose of this study was to clarify MIH prevalence rates and to consider potential regional differences throughout Japan. METHODS: A total of 4496 children aged 7-9 years throughout Japan were evaluated in this study. MIH prevalence rates among children were evaluated in eight regions throughout Japan. A child's residence was defined as the mother's residence during pregnancy. The localization of demarcated opacities and enamel breakdown was recorded on a standard code form using a guided record chart. Logistic regression analysis was used to evaluate whether MIH prevalence rates differed among age groups, sex, and regions. RESULTS: The overall prevalence of MIH in Japan was 19.8%. The prevalence of MIH was 14.0% in the Hokkaido region, 11.7% in the Tohoku region, 18.5% in the Kanto Shin-Etsu region, 19.3% in the Tokai Hokuriku region, 22.3% in the Kinki region, 19.8% in the Chugoku region, 28.1% in the Shikoku region, and 25.3% in the Kyushu region. These regional differences were statistically significant. Moreover, MIH prevalence rates decreased with age. No significant sex differences in MIH prevalence rates were demonstrated. CONCLUSIONS: To our knowledge, this is the first MIH study carried out in several regions throughout Japan. Regional differences existed in MIH prevalence rates; particularly, MIH occurred more frequently in children residing in southwestern areas than those in northeastern areas of Japan.

Galanin-induced decreases in nucleus accumbens/striatum excitatory postsynaptic potentials and morphine conditioned place preference require both galanin receptor 1 and galanin receptor 2.

The neuropeptide galanin has been shown to alter the rewarding properties of morphine. To identify potential cellular mechanisms that might be involved in the ability of galanin to modulate opiate reward, we measured excitatory postsynaptic potentials (EPSPs), using both field and whole-cell recordings from striatal brain slices extracted from wild-type mice and mice lacking specific galanin receptor (GalR) subtypes. We found that galanin decreased the amplitude of EPSPs in both the dorsal striatum and nucleus accumbens. We then performed recordings in slices from knockout mice lacking either the GalR1 or GalR2 gene, and found that the ability of galanin to decrease EPSP amplitude was absent from both mouse lines, suggesting that both receptor subtypes are required for this effect. In order to determine whether behavioral responses to opiates were dependent on the same receptor subtypes, we tested GalR1 and GalR2 knockout mice for morphine conditioned place preference (CPP). Morphine CPP was significantly attenuated in both GalR1 and GalR2 knockout mice. These data suggest that mesolimbic excitatory signaling is significantly modulated by galanin in a GalR1-dependent and GalR2-dependent manner, and that morphine CPP is dependent on the same receptor subtypes.

Effects of BMS-902483, an α7 nicotinic acetylcholine receptor partial agonist, on cognition and sensory gating in relation to receptor occupancy in rodents.

The α7 nicotinic acetylcholine receptor is thought to play an important role in human cognition. Here we describe the in vivo effects of BMS-902483, a selective potent α7 nicotinic acetylcholine receptor partial agonist, in relationship to α7 nicotinic acetylcholine receptor occupancy. BMS-902483 has low nanomolar affinity for rat and human α7 nicotinic acetylcholine receptors and elicits currents in cells expressing human or rat α7 nicotinic acetylcholine receptors that are about 60% of the maximal acetylcholine response. BMS-902483 improved 24h novel object recognition memory in mice with a minimal effective dose (MED) of 0.1mg/kg and reversed MK-801-induced deficits in a rat attentional set-shifting model of executive function with an MED of 3mg/kg. Enhancement of novel object recognition was blocked by the silent α7 nicotinic acetylcholine receptor agonist, NS6740, demonstrating that activity of BMS-902483 was mediated by α7 nicotinic acetylcholine receptors. BMS-902483 also reversed ketamine-induced deficits in auditory gating in rats, and enhanced ex vivo hippocampal long-term potentiation examined 24h after dosing in mice. Results from an ex vivo brain homogenate binding assay showed that α7 receptor occupancy ranged from 64% (novel object recognition) to ~90% (set shift and gating) at the MED for behavioral and sensory processing effects of BMS-902483.

Impaired synaptic plasticity and learning in mice lacking beta-adducin, an actin-regulating protein.

The adducin family of proteins interacts with the actin cytoskeleton and the plasma membrane in a calcium- and cAMP-dependent manner. Thus, adducins may be involved in changes in cytoskeletal organization resulting from synaptic stimulation. beta-Adducin knock-out mice were examined in physiological and behavioral paradigms related to synaptic plasticity to elucidate the role the adducin family plays in processes underlying learning and memory. In situ hybridization for alpha- and beta-adducin demonstrates that these mRNAs are found throughout the brain, with high levels of expression in the hippocampus. Schaffer collateral-CA1 tetanic long-term potentiation decayed rapidly in acute hippocampal slices from beta-adducin knock-out mice, although baseline spine morphology and postsynaptic density were normal. Interestingly, the input-output relationship was significantly increased in hippocampal slices from beta-adducin knock-out mice. Furthermore, beta-adducin knock-out mice were impaired in performance of fear conditioning and the water maze paradigm. The current results indicate that beta-adducin may play an important role in the cellular mechanisms underlying activity-dependent synaptic plasticity associated with learning and memory.

Reversible septal inactivation disrupts hippocampal slow-wave and unit activity and impairs trace conditioning in rabbits (Oryctolagus cuniculus).

This study investigated the effects of medial septal microinfusion of the local anesthetic, procaine (MS Pro), on hippocampal neurophysiology and learning of the rabbit (Oryctolagus cuniculus) classically conditioned jaw movement (CJM) response. Both the percentage and the amplitude of hippocampal theta decreased after procaine administration, and unit recordings from the MS Pro group showed significantly smaller conditioning-related hippocampal neural responses than those from controls. The MS Pro group took significantly longer to reach learning criterion than did the control group. Interpreted in the context of previous studies, the present result suggests that nonselective blocking of all septal projection systems, as well as fibers of passage, using procaine can be less detrimental to learning than an imbalance between GABAergic and cholinergic septohippocampal projections, as produced by septal infusion of anticholinergics.

Theta-contingent trial presentation accelerates learning rate and enhances hippocampal plasticity during trace eyeblink conditioning.

Hippocampal theta activity has been established as a key predictor of acquisition rate in rabbit (Orcytolagus cuniculus) classical conditioning. The current study used an online brain--computer interface to administer conditioning trials only in the explicit presence or absence of spontaneous theta activity in the hippocampus-dependent task of trace conditioning. The findings indicate that animals given theta-contingent training learned significantly faster than those given nontheta-contingent training. In parallel with the behavioral results, the theta-triggered group, and not the nontheta-triggered group, exhibited profound increases in hippocampal conditioned unit responses early in training. The results not only suggest that theta-contingent training has a dramatic facilitory effect on trace conditioning but also implicate theta activity in enhancing the plasticity of hippocampal neurons.

Differential mastication kinematics of the rabbit in response to food and water: implications for conditioned movement.

Analysis of naturalistic chewing patterns may provide insight into mapping the neural substrates of jaw movement control systems, including their adaptive modification during the classically conditioned jaw movement (CJM) paradigm. Here, New Zealand White rabbits were administered food and water stimuli orally to evaluate the influence of stimulus consistency on masticatory pattern. Chewing patterns were recorded via video camera and movements were analyzed by computerized image analysis. The mandibular kinematics, specifically the extent of dorsal/ventral, medial/lateral, and rostral/caudal movement, were significantly larger in food-evoked than water-evoked chewing. Water-evoked chewing frequency, however, was significantly higher than that of food-evoked movements. In light of known cortical mastication modulatory centers, our findings implicate different neural substrates for the responses to food and water stimuli in the rabbit. A detailed delineation of jaw movement patterns and circuitry is essential to characterize the neural substrates of CJM.

Hippocampal synaptic plasticity is impaired in the Mecp2-null mouse model of Rett syndrome.

Rett syndrome is an X-linked neurodevelopmental disorder caused by mutations in the gene encoding the transcriptional repressor methyl-CpG-binding protein 2 (MeCP2). Here we demonstrate that the Mecp2-null mouse model of Rett syndrome shows an age-dependent impairment in hippocampal CA1 long-term potentiation induced by tetanic or theta-burst stimulation. Long-term depression induced by repetitive low-frequency stimulation is also absent in behaviorally symptomatic Mecp2-null mice. Immunoblot analyses from behaviorally symptomatic Mecp2-null mice reveal altered expression of N-methyl-d-aspartate receptor subunits NR2A and NR2B. Presynaptic function is also affected, as demonstrated by a significant reduction in paired-pulse facilitation. Interestingly, the properties of basal neurotransmission are normal in the Mecp2-null mice, consistent with our observations that the levels of expression of synaptic and cytoskeletal proteins, including glutamate receptor subunits GluR1 and GluR2, PSD95, synaptophysin-1, synaptobrevin-2, synaptotagmin-1, MAP2, betaIII-tubulin and NF200, are not significantly altered. Together, these data provide the first evidence that the loss of Mecp2 expression is accompanied by age-dependent alterations in excitatory synaptic plasticity that are likely to contribute to the cognitive and functional deficits underlying Rett syndrome.

Nonpharmacological amelioration of age-related learning deficits: the impact of hippocampal theta-triggered training.

Age-related learning deficits are often attributed to deterioration of hippocampal function. Conversely, a well studied index of hippocampal activity, the rhythm, is known to enhance hippocampal plasticity and accelerate learning rate in young subjects, suggesting that manipulations of activity might be used as a means to counteract impairments related to the aging process. Here, young and older rabbits were given eyeblink conditioning trials either when exhibiting hippocampal (+) or regardless of hippocampal activity (yoked control). Although, as expected, older-yoked control animals showed a learning deficit, the older + group learned as fast as young controls, demonstrating that aging deficits, at least in eyeblink classical conditioning, can be overcome by giving trials during episodes of hippocampal activity. The use of several learning criteria showed that the benefits of hippocampal occur in multiple phases of learning that may depend on different cognitive or motor processes. Whereas there was a benefit of -triggered training in both age groups during the early phase of acquisition, the enhancement persisted in older animals, peaking during later performance. These findings have implications for theories of age-related memory deficits and may contribute to the development of beneficial treatments.

Oscillatory brain states and learning: Impact of hippocampal theta-contingent training.

Eyeblink classical conditioning is a relatively simple form of associative learning that has become an invaluable tool in our understanding of the neural mechanisms of learning. When studying rabbits in this paradigm, we observed a dramatic modification of learning rate by conducting training during episodes of either hippocampal theta or hippocampal non-theta activity as determined by on-line slow-wave spectral analysis. Specifically, if animals were given trials only when a computer analysis verified a predominance of slow-wave oscillations at theta frequencies (3-8 Hz), they learned in half as many trials as animals trained during non-theta hippocampal activity (58 vs. 115). This finding provides important evidence from awake, behaving animals that supports recent advances in our knowledge of (i) brain sites and neurobiological mechanisms of learning and memory, specifically hippocampus and theta oscillations, (ii) the biological plausibility of current models of hippocampal function that posit important roles for oscillatory potentials, and (iii) the design of interfaces between biological and cybernetic (electronic) systems that can optimize cognitive processes and performance.