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A commentary published in Frontiers in Ecology & Evolution discusses a study on the generative power of language in birds, specifically the Japanese tit. The study suggests that these birds have evolved a cognitive capacity called "core-Merge," which allows them to combine two words into a single unit. The researchers conducted experiments that showed the birds respond differently to alert-recruitment call sequences compared to separate alert and recruitment calls, indicating that they recognize the sequence as a single unit. The commentary addresses criticisms of the study and argues that the results provide evidence for core-Merge. The text also discusses conflicting theories on the origins of language's productivity. [Extracted from the article]

One of the cognitive capacities underlying language is core-Merge, which allows senders to combine two words into a sequence and receivers to recognize it as a single unit. Recent field studies suggest intriguing parallels in non-human animals, e.g., Japanese tits (Parus minor) combine two meaning-bearing calls into a sequence when prompting antipredator displays in other individuals. However, whether such examples represent core-Merge remains unclear; receivers may perceive a two-call sequence as two individual calls that are arbitrarily produced in close time proximity, not as a single unit. If an animal species has evolved core-Merge, its receivers should treat a two-call sequence produced by a single individual differently from the same two calls produced by two individuals with the same timing. Here, we show that Japanese tit receivers exhibit antipredator displays when perceiving two-call sequences broadcast from a single source, but not from two sources, providing evidence for core-Merge in animals. It has been hypothesized that language depends on a capacity to produce and recognize two items (e.g., "come" + "talk") as a single unit (e.g., "come talk"). Here, the authors show that a wild passerine also uses this capacity in vocal communication. [ABSTRACT FROM AUTHOR]

The hormone melatonin is synthesized from serotonin by two enzymatic reactions (AANAT and ASMT/HIOMT) in the pineal gland following a circadian rhythm with low levels during the day and high levels at night. The robust nightly peak of melatonin secretion is an output signal of the circadian clock to the whole organism. However, so far the regulatory roles of endogenous melatonin in mammalian biological rhythms and physiology processes are poorly understood. Here, we establish congenic mouse lines (>N10 generations) that are proficient or deficient in melatonin synthesis (AH+/+ or AH−/− mice, respectively) on the C57BL/6J genetic background by crossing melatonin‐proficient MSM/Ms with C57BL/6J. AH+/+ mice displayed robust nightly peak of melatonin secretion and had significantly higher levels of pineal and plasma melatonin vs AH−/− mice. Using this mice model, we investigated the role of endogenous melatonin in regulating multiple biological rhythms, physiological processes, and rhythmic behaviors. In the melatonin‐proficient (AH+/+) mice, the rate of re‐entrainment of wheel‐running activity was accelerated following a 6‐hour phase advance of dark onset when comparted with AH−/− mice, suggesting a role of endogenous melatonin in facilitating clock adjustment. Further in the AH+/+ mice, there was a significant decrease in body weight, gonadal weight and reproductive performance, and a significant increase in daily torpor (a hypothermic and hypometabolic state lasting only hours during adverse conditions). Endogenous melatonin, however, had no effect in the modulation of the diurnal rhythm of 2‐[125I]‐iodomelatonin receptor expression in the SCN, free‐running wheel behavior in constant darkness, life span, spontaneous homecage behaviors, and various types of social‐emotional behaviors. The findings also shed light on the role of endogenous melatonin in mice domestication and provide new insights into melatonin's action in reducing energy expenditure during a food shortage. In summary, the congenic mice model generated in this study offers a significant advantage toward understanding of the role of endogenous melatonin in regulating melatonin receptor‐mediated rhythm behaviors and physiological functions. [ABSTRACT FROM AUTHOR]

A correction is presented to the article "Intake of 25-hydroxyvitamin D3 reduces duration and severity of upper respiratory tract infection: A randomized, double-blind, placebo-controlled, parallel group comparison study " which appeared in the January 05, 2018 issue.

Several studies have reported regulatory effects of estrogens on fear conditioning in female rodents. However, these studies used different doses, durations, and/or administration methods, and reported inconsistent results. To clarify the effect of estrogen on fear conditioning, we investigated the effects of different doses and durations of estradiol administration on freezing behavior during contextual fear conditioning in ovariectomized (OVX) mice. In Experiment 1, OVX ICR mice received a single subcutaneous (s.c.) injection of either oil vehicle (control, 0.1 ml sesame oil) or varied doses (0.5 μg/0.1 ml, 5 μg/0.1 ml, or 50 μg/0.1 ml) of 17β-estradiol-3-benzoate (EB). Fear conditioning was conducted two days post-EB treatment, and the mice were tested for the learned fear response the following day. In Experiment 2, OVX female mice received an s.c. implantation of a Silastic capsule (I.D. 1.98 × 20.0 mm) containing either vehicle or varied doses (0.05 μg/0.1 ml, 0.5 μg/0.1 ml, 5 μg/0.1 ml, 50 μg/0.1 ml) of EB. Two weeks after implantation, fear conditioning was conducted. During the tests conducted 24 h after conditioning, the high dose EB group showed longer freezing times in both experiments, and lower locomotor activity compared to the control or lower dose groups. In Experiment 3, serum estradiol concentrations of the mice that were treated like those in Experiment 2, were measured; the serum levels of estradiol increased linearly according to the dose of EB administered. The results suggest that mice treated with a high dose of EB exhibit enhanced fear learning, regardless of treatment duration. As a woman’s vulnerability to emotional disorders increases in the peripregnancy period, during which estrogen levels are high, the results from the high-dose EB groups may be important for understanding the hormonal mechanisms involved in these disorders. [ABSTRACT FROM AUTHOR]

Objectives: This study aimed to assess the effect of 25-hydroxyvitamin D3 (25OHD) which is a hydroxide of vitamin D3 ingestion on upper respiratory tract infection (URTI).Design and Setting: A prospective, randomized, double-blind, placebo-controlled study was performed from December 2015 to September 2016 in the Nihonbashi Egawa Clinic, Kei Medical Office TOC Building Medical Clinic, and Medical Corporation Kaiseikai Kita-Shinyokohama Medical Clinic, in Japan.Participants: Four hundred twenty eight participants aged 45-74 years were screened by their serum 25-hydoroxyvitamin D concentration.Intervention: The participants were randomized to either 25OHD (10 μg/day) or placebo capsule, daily, for 16 consecutive weeks.Measurements: The primary outcome measure was the incidence proportion of URTI, and the secondary outcome measures were the physical severity score, the quality-of-life (QOL) score, the duration of URTI, and the incidence proportion of new URTI events every four weeks. Data were collected using cold diary Wisconsin Upper Respiratory Symptom Survey-21 (WURSS-21) during the intervention.Results: Of 428 participants screened, 252 with serum 25-hydroxyvitamn D levels were deficient or insufficient (75 nmol/L or less) were enrolled in this study. Of these, 105 placebo and 110 25OHD group subjects completed the study. For the incidence proportion of URTI, no effect of 25OHD intake was observed. On the other hand, the duration of URTI was shorter in the 25OHD (P = 0.061) compared to placebo. For the incidence proportion of URTI every four weeks, the incidence of new URTI was decreased in both groups over the time of intake. However, when the 25OHD and the placebo were compared, a decrease in the incidence proportion of URTI was seen earlier in the 25OHD. When the total physical severity score and the total QOL score during the study were assessed, they both were significantly improved in the 25OHD compared to placebo.Conclusions: The intake of 25OHD may reduce the duration of URTI, the physical severity, and the QOL when suffering from URTI. [ABSTRACT FROM AUTHOR]

Mice produce ultrasonic vocalizations featuring a variety of syllables. Vocalizations are observed during social interactions. In particular, males produce numerous syllables during courtship. Previous studies have shown that vocalizations change according to sexual behavior, suggesting that males vary their vocalizations depending on the phase of the courtship sequence. To examine this process, we recorded large sets of mouse vocalizations during male–female interactions and acoustically categorized these sounds into 12 vocal types. We found that males emitted predominantly short syllables during the first minute of interaction, more long syllables in the later phases, and mainly harmonic sounds during mounting. These context- and time-dependent changes in vocalization indicate that vocal communication during courtship in mice consists of at least three stages and imply that each vocalization type has a specific role in a phase of the courtship sequence. Our findings suggest that recording for a sufficiently long time and taking the phase of courtship into consideration could provide more insights into the role of vocalization in mouse courtship behavior in future study. [ABSTRACT FROM AUTHOR]

We previously showed that treatment of mice with the Flt3 ligand (Flt3L) prevents development of lethal experimental cerebral malaria and inhibits parasitemia during Plasmodium berghei ANKA (PbA) infection. In this study, we investigated the mechanisms underlying the reduction of parasitemia in Flt3L-treated mice. Studies using gene knockout mice and antibody treatment indicated that the anti-parasitemia effect of Flt3L was mediated by innate immune system and was dependent on MyD88, IFN-γ, IL-12 and natural killer ( NK) cells. The number of NK cells and their ability to produce IFN-γ was enhanced in Flt3L-treated mice. Phagocytic activity of splenocytes was increased in Flt3L-treated mice after PbA infection when compared with that in untreated mice, and this activity was mainly mediated by the accumulation of F4/80mid CD11b+ cells in the spleen. In both MyD88 −/− and IFN-γ −/− mice, the proportion of F4/80mid CD11b+ cells was not increased in the spleen of Flt3L-treated mice after infection. These correlations suggest that NK cells produce IFN-γ in Flt3L-treated mice, and accumulation of F4/80mid CD11b+ cells in the spleen is promoted by an IFN-γ -dependent manner, culminating in the inhibition of parasitemia. These findings imply that Flt3L promotes effective innate immunity against malaria infection mediated by interplay among varieties of innate immune cells. [ABSTRACT FROM AUTHOR]

Aim To evaluate ex vivo effectiveness of the three formulations of bleaching materials for intracoronal bleaching of root filled teeth using the walking bleach technique. Methodology Extracted premolar teeth were stained artificially with human blood. After biomechanical preparation, the root canals were filled and a 3-mm thick intermediate base of zinc phosphate cement was placed at the level of the cementoenamel junction. The teeth were divided into four groups ( n = 12): C (control, without bleaching material), A1 (sodium perborate + distilled water), A2 (sodium perborate + 10% carbamide peroxide) and A3 (sodium perborate + 35% carbamide peroxide). The bleaching materials were changed at 7 and 14 days. Evaluation of shade was undertaken with aid of the VITA Easyshade™ (Δ E* ab) and was performed after tooth staining and at 7, 14 and 21 days after bleaching, based on the CIELAB system. Data were analysed byanova for repeated measurements, Tukey and Dunnett tests (α = 0.05). Results The Tukey test revealed that group A1 (10.58 ± 4.83 Δ E* ab) was statistically different from the others (A2, 19.57 ± 4.72 Δ E* ab and A3, 17.58 ± 3.33 Δ E* ab), which were not different from each other. At 7 days: A1 was significantly different from A2; at 14 and 21 days: A2 and A3 were significantly better than A1; the Dunnett test revealed that the control group was different from A1, A2 and A3 at all periods ( P < 0.05). Conclusion Sodium perborate associated with both 10% and 35% carbamide peroxide was more effective than when associated with distilled water. [ABSTRACT FROM AUTHOR]

A number of consistent clinical observations provide direction for the hypothesis that pathological sensitization of neuronal systems may be an important factor for relapse or the onset of stimulant-induced psychosis (eg, methamphetamine or amphetamine psychosis, cocaine psychosis and phencyclidine psychosis) and schizophrenia. First, psychotic symptoms can be produced in normal subjects by stimulants. Secondly, a large portion of schizophrenic patients exhibit exacerbation of psychotic symptoms in response to stimulants at doses which would not be psychotogenic in normal subjects. Lastly, the ability of stress to precipitate the onset and relapse of schizophrenia is well documented. In this regard, acute responses to stimulants provide useful information for relapse prediction of schizophrenia and substance abuse. This paper addresses the nature and role of pathological sensitization in relapse of stimulant- and phencyclidine-induced psychosis and schizophrenia, and its relation to pathophysiology of schizophrenia. [ABSTRACT FROM AUTHOR]

Abstract Increased sensitivity to stress associated with noradrenergic hyperactivity and dopaminergic changes may precipitate stress-related psychiatric disorders. The present study examines the relation between this increased sensitivity and vulnerability to subsequent spontaneous recurrences of methamphetamine (MAP) psychosis (i.e. flashbacks). Plasma monoamine metabolite levels were assayed in 18 subjects with flashbacks, of whom ten experienced a single flashback and eight experienced further subsequent flashbacks; in 21 subjects with a history of MAP psychosis who did not experience flashbacks; and 33 controls. A square-root transformation was applied to monoaminergic values, rendering the distribution normal. The subjects with flashbacks had undergone frightening stressful experiences during previous MAP use. The dominant factor triggering flashbacks was a mild tear of other people. During flashbacks, plasma noradrenaline levels markedly increased and 3-methoxytyramine levels, an indicator of dopamine release, were elevated. Among the 18 subjects with flashbacks, the ten with subsequent flashbacks had markedly increased noradrenaline levels during flashbacks, whereas the eight with a single flashback displayed small increases in noradrenaline levels as well as 3-methoxytyramine levels. Thus, a mild fear of other people may have elicited memories of MAP psychosis, related to frightening stressful experiences through increased sensitivity to stress associated with noradrenergic hyperactivity, involving increased dopamine release. Robust noradrenergic hyperreactivity to mild stress may predispose subjects to subsequent flashbacks. [ABSTRACT FROM AUTHOR]

Abstract We studied the factors precipitating spontaneous recurrences of methamphetamine (MAP)-induced paranoid-hallucinatory states (referred to as "flashbacks") in 28 flashbackers, along with 18 non-flashbackers with a history of MAP psychosis. Plasma levels of catecholamines and their metabolites were assayed in the 28 flashbackers, the 18 non-flashbackers, 8 subjects with persistent MAP psychosis, and 33 normal controls (22 MAP users and 11 non-users). The flashbackers had been exposed to significantly higher numbers of stressful events, and/or MAP-induced frightening paranoid-hallucinatory states during previous MAP use, than the non-flashbackers. Factors triggering the flashbacks met the DSM-III-R criteria for a mild psychosocial stressor. During flashbacks, plasma norepinephrine levels increased and plasma levels of 3-methoxytyramine, which is an indicator of dopamine release, showed a smaller increase. It follows that stressful experiences together with MAP use may induce sensitization to mild psychosocial stressors. Noradrenergic hyperactivity and some degree of increased dopamine release may be involved in this process. Stress sensitization may elicit memories of MAP psychosis associated with stressful experiences in response to mild psychosocial stressors, leading to the occurrence of flashbacks. Sensitization to stress associated with noradrenergic hyperactivity, involving increased dopamine release may be central to spontaneous recurrences of MAP psychosis. [ABSTRACT FROM AUTHOR]

Abstract This paper examines noradrenergic hyperactivity in response to stress in the development of spontaneous recurrences of methamphetamine (MAP) psychosis, a phenomenon known as flashbacks, in studies of psychedelic drug use. We studied predictors of flashbacks in 36 subjects with flashbacks, along with 80 subjects with a histroy of MAP psychosis who did not experience flashbacks. Plasma monoamine metabolite levels were assayed in 26 of the 36 subjects with flashbacks, 16 of the 80 subjects without flashbacks, nine subjects with persistent MAP psychosis, and 28 normal controls. None of the 28 controls became psychotic. A square root transformation was applied to all monoaminergic values, resulting in data nearly normally distributed. The subjects with flashbacks had been exposed to stressful events or threatening paranoid-hallucinatory states or both during previos MAP use. Most flashbacks occurred under conditions that provoked a mild fear of other people. Plasma norepinephrine levels were markedly increased during flashbacks. Thus, stressful experiences together with MAP use may have induced noradrenergic hyperreactivity to a mild stress, which in turn may elicit memories of MAP psychosis associated with stressful experiences. A mild fear of other people precipitated the flashbacks, including markedly increased noradrenergic activity. The results of this study suggest that noradrenergic hyperreactivity to a mild stress is a precipitating factor in spontaneous recurrences of MAP psychosis. [ABSTRACT FROM AUTHOR]