Electrocardiographic activity depends on the relative position between intimate persons.

Interpersonal space (IPS) refers to the area surrounding the body in which we engage in social interactions while maintaining our comfort. Numerous previous studies have reported the psychological and physiological changes associated with the proximity of two people engaged in face-to-face interaction. Currently, there is limited knowledge about how the relative position between two socially intimate individuals affects their psychological and physiological states. This research measured the subjective discomfort and electrocardiographic responses of participants when standing static at various relative positions. The highest discomfort, lowest heart rate, and highest heart rate variability (HRV; parasympathetic activity index) were observed when the friend stood in the face-to-face position. Interestingly, heart rate also decreased when the friend stood on the right side, although HRV did not change. We interpreted the results as suggesting that the presence of a familiar person elicits the electrocardiographic responses associated with an increase in parasympathetic activity.

Direct gaze enhances interoceptive accuracy.

Direct-gaze signals are known to modulate human cognition, including self-awareness. In the present study, we specifically focused on 'bodily' self-awareness and examined whether direct gaze would modulate one's interoceptive accuracy (IAcc)-the ability to accurately monitor internal bodily sensations. While viewing a photograph of a frontal face with a direct gaze, an averted face or a mere white cross as a baseline, participants were required to count their heartbeats without taking their pulse. The results showed higher IAcc in the direct-gaze condition than in the averted-face or baseline condition. This was particularly the case in participants with low IAcc at baseline, indicating that direct gaze enhanced the participants' IAcc. Importantly, their heart rate was not different while viewing the direct gaze and averted face, suggesting that sensitivity to interoceptive signals, rather than physiological arousal, is heightened by direct gaze. These findings demonstrate the role of social signals in our bodily interoceptive processing and support the notion of the social nature of self-awareness.

Automatic facial mimicry in response to dynamic emotional stimuli in five-month-old infants.

Human adults automatically mimic others' emotional expressions, which is believed to contribute to sharing emotions with others. Although this behaviour appears fundamental to social reciprocity, little is known about its developmental process. Therefore, we examined whether infants show automatic facial mimicry in response to others' emotional expressions. Facial electromyographic activity over the corrugator supercilii (brow) and zygomaticus major (cheek) of four- to five-month-old infants was measured while they viewed dynamic clips presenting audiovisual, visual and auditory emotions. The audiovisual bimodal emotion stimuli were a display of a laughing/crying facial expression with an emotionally congruent vocalization, whereas the visual/auditory unimodal emotion stimuli displayed those emotional faces/vocalizations paired with a neutral vocalization/face, respectively. Increased activation of the corrugator supercilii muscle in response to audiovisual cries and the zygomaticus major in response to audiovisual laughter were observed between 500 and 1000 ms after stimulus onset, which clearly suggests rapid facial mimicry. By contrast, both visual and auditory unimodal emotion stimuli did not activate the infants' corresponding muscles. These results revealed that automatic facial mimicry is present as early as five months of age, when multimodal emotional information is present.

Orthographic Reading Deficits in Dyslexic Japanese Children: Examining the Transposed-Letter Effect in the Color-Word Stroop Paradigm.

In orthographic reading, the transposed-letter effect (TLE) is the perception of a transposed-letter position word such as "cholocate" as the correct word "chocolate." Although previous studies on dyslexic children using alphabetic languages have reported such orthographic reading deficits, the extent of orthographic reading impairment in dyslexic Japanese children has remained unknown. This study examined the TLE in dyslexic Japanese children using the color-word Stroop paradigm comprising congruent and incongruent Japanese hiragana words with correct and transposed-letter positions. We found that typically developed children exhibited Stroop effects in Japanese hiragana words with both correct and transposed-letter positions, thus indicating the presence of TLE. In contrast, dyslexic children indicated Stroop effects in correct letter positions in Japanese words but not in transposed, which indicated an absence of the TLE. These results suggest that dyslexic Japanese children, similar to dyslexic children using alphabetic languages, may also have a problem with orthographic reading.

Delayed disengagement of attention from snakes in children with autism.

In the visual search task, it is well known that detection of a tilted straight line as the target among vertical lines that act as distractors is easier than vice versa, and that detection of a snake image as the target among flower images is easier than vice versa. In this study, the degree of such search asymmetry was compared between 18 children with autism and 14 typically developing (TD) children. The results revealed that compared to TD children, children with autism were disproportionally slow when asked to detect the flower among the snake images, suggesting the possibility that they experienced difficulty of disengaging their attention from the snake images. This delayed disengagement would serve itself as an enhanced attentional bias toward snakes in children with autism that is similar to characteristics of visual search performance in anxiety patients.

Absence of predispositional attentional sensitivity to angry faces in children with autism spectrum disorders.

A rapid allocation of attention towards threatening stimuli in the environment is crucial for survival. Angry facial expressions act as threatening stimuli, and capture humans' attention more rapidly than emotionally positive facial expressions - a phenomenon known as the Anger Superiority Effect (ASE). Despite atypical emotional processing, adults with Autism Spectrum Disorders (ASD) have been reported to show ASE similar to typically developed (TD) individuals. One important question is whether the basic process for ASE is intact in individuals with ASD or whether instead they acquire an alternative process that enables ASE. To address this question, we tested the prevalence of ASE in young children with and without ASD using a face-in-the-crowd task. ASE was clearly observed in TD children, whereas ASD children did not show the effect. In contrast to previous reports of ASE in adults or relatively older children with ASD, our results suggest that in ASD basic predispositional mechanisms to allocate attention quickly towards angry faces are not preserved.

Preliminary evidence that different mechanisms underlie the anger superiority effect in children with and without Autism Spectrum Disorders.

Previous studies have demonstrated that angry faces capture humans' attention more rapidly than emotionally positive faces. This phenomenon is referred to as the anger superiority effect (ASE). Despite atypical emotional processing, adults and children with Autism Spectrum Disorders (ASD) have been reported to show ASE as well as typically developed (TD) individuals. So far, however, few studies have clarified whether or not the mechanisms underlying ASE are the same for both TD and ASD individuals. Here, we tested how TD and ASD children process schematic emotional faces during detection by employing a recognition task in combination with a face-in-the-crowd task. Results of the face-in-the-crowd task revealed the prevalence of ASE both in TD and ASD children. However, the results of the recognition task revealed group differences: In TD children, detection of angry faces required more configural face processing and disrupted the processing of local features. In ASD children, on the other hand, it required more feature-based processing rather than configural processing. Despite the small sample sizes, these findings provide preliminary evidence that children with ASD, in contrast to TD children, show quick detection of angry faces by extracting local features in faces.

Intensive exposure to narrative in story books as a possibly effective treatment of social perspective-taking in schoolchildren with autism.

One of the major characteristics of autism is impairment of communication and socialization. While such impairment per se has been well documented, research into effective interventions for children with this developmental disorder is still limited. Here we present preliminary evidence for the possibility of improvement of the capability of social perspective-taking in schoolchildren with autism by having intensive experience with narrative, in which they were exposed to narrative in story books read by their parents over a consecutive 5- to 6-day-period. When their capability was evaluated on the basis of a conventional role-taking task, the mean score tended to increase after the exposure as compared to before the exposure, whereas such a change was not recorded in children who did not experience such exposure. These effects were confirmed when the children were retested 4 months later. Although preliminary, the current study represents a step toward the development of more effective social perspective-taking interventions for children with autism.

Viewing images of snakes accelerates making judgements of their colour in humans: red snake effect as an instance of 'emotional Stroop facilitation'.

One of the most prevalent current psychobiological notions about human behaviour and emotion suggests that prioritization of threatening stimuli processing induces deleterious effects on task performance. In order to confirm its relevancy, 108 adults and 25 children were required to name the colour of images of snakes and flowers, using the pictorial emotional Stroop paradigm. When reaction time to answer the colour of each stimulus was measured, its value was found to decrease when snake images were presented when compared with when flower images were presented. Thus, contrary to the expectation from previous emotional Stroop paradigm research, emotions evoked by viewing images of snakes as a biologically relevant threatening stimulus were found to be likely to exert a facilitating rather than interfering effect on making judgements of their colour.

Estrogen biosynthesis in the gonad of the frog Rana rugosa.

In certain species of amphibians gonadal differentiation is influenced by steroid hormones. In the case of the frog Rana rugosa testosterone given to tadpoles reverses sex from female to male, while the opposite reversal - male to female - can be achieved using estradiol-17ß. In this study, we investigated whether CYP19 (P450 aromatase), the enzyme responsible for a production of estradiol-17ß, was present in the differentiating gonad of R. rugosa. Initially, we immunized rabbits against frog CYP19 peptides and performed immunostaining using specific antibodies purified from that serum. CYP19-reactive signals were observed in gonadal somatic cells of the female, but not male tadpoles at stage (St.) I (the stage prior to phenotypic sex determination in tadpoles of R. rugosa). Immunopositive signals were also produced in ovarian somatic cells froglets at St. XXV (just after the completion of metamorphosis). We also examined the enzymatic activity of CYP19 in the differentiating gonad of R. rugosa. Reverse-phase HPLC (high performance liquid chromatography) analysis revealed that [(3)H]testosterone was converted to [(3)H]estradiol-17ß in the gonad of tadpoles at St. I. Interestingly, the rate of conversion was much higher in females than in males. To the best of our knowledge, this is the first report on the biosynthesis of estradiol-17ß in the gonad of amphibians, and the co-incident identification of active CYP19 enzyme in the differentiating gonad of R. rugosa. Based on our results, we conclude that estradiol-17ß may be involved in ovarian differentiation in this species.

Structural changes in gonadal basement membranes during sex differentiation in the frog Rana rugosa.

Here we report that structural changes in gonadal basement membranes during sex differentiation in the frog Rana rugosa are revealed using an antibody to its laminin component. Immunohistochemical staining indicated that the first sexual dimorphism appeared in testicular cords and ovarian cavities in differentiating gonads of tadpoles at St. 25-3W, three weeks after they reached St. 25. During development, as the testis enlarged, testicular cord partitions appeared to form by invagination of the testicular epithelium. Ovarian cavities also increased in volume. Laminin-positive basement membranes initially surrounded a partial surface of oocytes close to the ovarian cavity, fully covering growing oocytes by St. X. Laminin-reactive signals were present in somatic cells outside seminiferous tubules in the testis and outside oocytes in one-year-old frogs. BrdU-labeling showed that the number of dividing germ cells increased continuously in male gonads but increased in females only up to St. V, declining at St. X and thereafter. The number of dividing germ cells declined when the basement membranes had fully covered the oocytes. Together, these findings suggest that the first sexual dimorphism in the gonad of R. rugosa first appears as a structural change in the basement membranes. Finally, we speculate that the basement membrane on the surface of oocytes may affect their proliferation in this species.