Shigekazu Higuchi

Kyushu University | Kyudai · Faculty of Design, Department of Human Science

Context: The sensitivity of melatonin to light suppression is expected to be higher in children because children have large pupils and pure crystal lenses. However, melatonin suppression by light in children remains unclear. Objective: We investigated whether light-induced melatonin suppression in children is larger than that in adults. Methods...

Our aim was to determine the association between melanopsin gene polymorphism and pupillary light reflex under diverse photic conditions, including different intensities andwavelengths. A total of 195 visually corrected subjects volunteered for investigation of the melanopsin gene of single nucleotide polymorphism (SNP) of rs1079610 (I394T). The ge...

Sleep debt reportedly increases emotional instability, such as anxiety and confusion, in addition to sleepiness and psychomotor impairment. However, the neural basis of emotional instability due to sleep debt has yet to be elucidated. This study investigated changes in emotional responses that are elicited by the simulation of short-term sleep loss...

Epidemiological studies have shown that playing a computer game at night delays bedtime and shortens sleeping hours, but the effects on sleep architecture and quality have remained unclear. In the present study, the effects of playing a computer game and using a bright display on nocturnal sleep were examined in a laboratory. Seven male adults (24....

The purpose of the present study was to clarify the relationship between nighttime sleep and effectiveness of inpatient rehabilitation for stroke patients during convalescence. Fifteen patients participated. Nighttime sleep was measured by actigraph recording. Actual sleep time was significantly correlated with discharge motor Functional Independen...

Background Previous studies have reported that the sense of “self” is associated with specific brain regions and neural network activities. In addition, the mirror system, which functions when executing or observing an action, might contribute to differentiating the self from others and form the basis of the sense of self as a fundamental physical...

Background There is no consensus on reporting light characteristics in studies investigating non-visual responses to light. This project aimed to develop a reporting checklist for laboratory-based investigations on the impact of light on non-visual physiology. Methods A four-step modified Delphi process (three questionnaire-based feedback rounds a...

Humans have a circadian rhythm for which the period varies among individuals. In the present study, we investigated the amount of natural phase delay of circadian rhythms after spending a day under dim light (Day 1 to Day 2) and the amount of phase advance due to light exposure (8000 lx, 4100 K) the following morning (Day 2 to Day 3). The relations...

We aimed to establish a method for estimating dim light melatonin onset (DLMO) using mathematical slopes calculated from melatonin concentrations at three sampling points before and after sleep in children. The saliva of 30 children (mean age ± SD: 10.2 ± 1.3 years old) was collected under dim-light conditions up to six times every hour starting at...

Background The aim of this study was to examine the effect of others’ gaze on an observer’s microsaccades. We also aimed to conduct preliminary investigations on the relationship between the microsaccadic response to a gaze and a gazer’s facial expression and attention-deficit/hyperactivity disorder (ADHD) tendencies. Methods Twenty healthy underg...

Physiological effects of light exposure in humans are diverse. Among them, the circadian rhythm phase shift effect in order to maintain a 24-h cycle of the biological clock is referred to as non-visual effects of light collectively with melatonin suppression and pupillary light reflex. The non-visual effects of light may differ depending on age, an...

Background It is known that the circadian rhythm phase in adults can be advanced in a natural light-dark cycle without electrical lighting. However, the effect of advanced sleep-wake timing according to the natural light-dark cycle on children’s circadian phase is unclear. We investigated the effects of approximately 2 weeks of camping life with li...

Background It has been shown in laboratory experiments using human subjects that ingestion of the non-essential amino acid l -serine before bedtime enhances the advance of circadian phase induced by light exposure the next morning. In the present study, we tested the effect of ingestion of l -serine before bedtime on circadian phase in real life an...

Aesthetic preference occurs in everyday experience. Studies have suggested that aesthetic preference (such as observing other's motion) affects social interaction via enhanced neural processing. This study investigated the effect of aesthetic preference on neural activities, in response to walking motion. Twenty participants observed biological mot...

Background Blue-enriched white light at night has the potential to delay the circadian rhythm in daily life. This study was conducted to determine whether the use of high correlated color temperature (CCT) light at home at night is associated with delay of sleep timing in university students. Methods The survey was conducted in 2014–2015 in 447 un...

A nighttime nap is expected to mitigate melatonin suppression during night work by blocking light input to the retina, but it is unclear. In the present study, we investigated the effects of a nap break on melatonin level, subjective sleepiness, and vigilance performance during simulated night work. Eleven healthy young males (mean ± SD age: 22.2 ±...

A nighttime nap is expected to mitigate melatonin suppression during night work by blocking light input to the retina, but it is unclear. In the present study, we investigated the effects of a nap break on melatonin level, subjective sleepiness, and vigilance performance during simulated night work. Eleven healthy young males (mean ± SD age: 22.2 ±...

Purpose To investigate the contributions of ocular crystalline lens transmittance spectra and pupil size on age‐related differences in the magnitude of light‐induced melatonin suppression at night. The first aim was to demonstrate that spectral lens transmittance in children can be measured in vivo with a Purkinje image‐based system. The second aim...

A method for rapid and objective assessment of ocular lens density and transmittance is needed for research and clinical practice. The aim of this study was to determine whether the Purkinje image-based technique can be used for objective and accurate quantification of spectral density and transmittance of ocular media (the mainly crystalline lens)...

The mirror system is a brain network that gets activated during action performance and observation. Brain mu waves have been used as a mirror system activity index; however, mu rhythm is prone to contamination by occipital alpha wave activity, thus raising a concern regarding its reliability as an index of the mirror system activity. In this study,...

Exposure to light at night results in disruption of endogenous circadian rhythmicity and/or suppression of pineal melatonin, which can consequently lead to acute or chronic adverse health problems. In the present study, we investigated whether exposure to very dim light or very bright light for a short duration influences melatonin suppression, sub...

In this study, we investigated the effect of projecting a face image to a curved surface on brain activity related to facial expression cognition. The participants observed the facial expression images that appear on the curved surface (cylinder) and the flat surface. The EEG was measured, and event-related potentials such as N170, VPP and LPP, whi...

Background Child maltreatment is a major health and social welfare problem, with serious and longstanding consequences. Impulse control ability plays an important role in reducing the risk of child maltreatment. The aim of this study was to investigate the associations of oxytocin (OXT) and prolactin (PRL) with behavior inhibition using children’s...

Background: It is known that the activities of the mirror system are related to imitation and understanding of the intention of an action. It has been reported that the activity of the mirror system is higher for observations for imitating and understanding the intention of an action than for simple observations. However, observations that facilita...

Light-induced melatonin suppression in children is reported to be more sensitive to white light at night than that in adults; however, it is unclear whether it depends on spectral distribution of lighting. In this study, we investigated the effects of different color temperatures of LED lighting on children's mela-tonin secretion during the night....

BACKGROUND: Previous studies have demonstrated the importance of the inhibition of automatic imitation in social interactions. Additionally, cognitive traits are known to vary among individuals. According to the empathizing-systemizing (E-S) model, personality can be quantified by empathizing and systemizing drives in causal cognition. Since inhibi...

Age-related decrease of crystalline lens transmittance is thought to be a factor affecting non-image forming (NIF) responses such as melatonin suppression and pupillary light reflex (PLR). In this study, we estimated pupillary spectral sensitivities of children and young adults and we compared them. Fourteen healthy primary school children and thir...

Background: The human mirror neuron system exists in adults, and even in children. However, a significant, unanswered question in the literature concerns age differences in the effect of visual orientation of human body movements. The observation of actions performed by others is known to activate populations of neural cells called mirror neuron sy...

Background The psychological care of abused children in the child protection system is an urgent issue in Japan. Child abuse has a serious impact on children’s emotion and behavior, but there is virtually no evidence about how child abuse affects sleep, which is closely related to behavioral and emotional control. In this study, we sought to identi...

Procedure for evaluating emotional and behavioral problems. (DOCX)

Prevalence of sleep symptoms in abused children. (DOCX)

Brief sleep questionnaire (19 items). Please answer the following questions based on your recollection of how the child has slept over the past month. Describe the child’s sleeping habits on normal days rather than on days when something out of the ordinary occurred (eg, when the child caught a cold). (DOCX)

Background: It is known that emotion regulatory responses of humans are changed by the experiences they have, but in particular, they are changed by becoming a mother. A recent study has found how a woman's emotion regulatory response to a child's crying changes after becoming a mother. However, mothers' emotion regulatory responses other than tho...

Background There is a dearth of sleep questionnaires with few items and confirmed reliability and validity that can be used for the early detection of sleep problems in children. The aim of this study was to develop a questionnaire with few items and assess its reliability and validity in both children at high risk of sleep disorders and a communit...

Background: The circadian clock is modulated by the timing of ingestion or food composition, but the effects of specific nutrients are poorly understood. Objective: We aimed to identify the amino acids that modulate the circadian clock and reset the light-induced circadian phase in mice and humans. Methods: Male CBA/N mice were orally administered...

It is important to understand how photoreceptors contribute to non-image-forming visual functions to enable the design of light environments that support optimal circadian rhythm regulation. The purpose of this study was to investigate the contribution of melanopsin-expressing ganglion cells (mRGCs) to circadian rhythm regulation using the silent s...

Humans show various responses to the environmental stimulus in individual levels as “physiological variations.” However, it has been unclear if these are caused by genetic variations. In this study, we examined the association between the physiological variation of response to light-stimulus and genetic polymorphisms. We collected physiological dat...

Relative maps for the SNPs examined in this study. (A) Six SNPs on PER2 and (B) four SNPs on PER3 are numbered serially, and their rs numbers, alleles reported, and allele frequencies of JPT in the HapMap database are shown respectively. (TIF)

Melatonin profiles of the subjects. (A) The raw data of melatonin concentration in all the subjects. The bold line shows the average. The start time of light exposure (0 h) was individually set 3 and 3.5 hours before the midpoint of sleep of each subject. There was a large interindividual difference. The dots shows the melatonin concentration measu...

Ancestral allele frequencies of SNPs (A) in PER2 and (B) in PER3. Three groups, Subjects, Northern Kyushu and Ryukyu were genotyped in this study. N represents the number of individuals. (TIF)

Comparison of the distributions of percentages of melatonin suppression for major haplotypes of (A) PER2 and (B) PER3. The thick middle lines in the boxes represent the medians, and the tops and bottoms of the boxes represent the third and the first quartiles, respectively. One dot represents one chromosome, and the numbers of chromosomes, n, are s...

Difference of changes in percentages of melatonin suppression between the genotypes of PER2. The percentages of melatonin suppression by light exposure in Hap1, Hap2, and Hap3 homozygotes. The data are shown as the mean + SD. (TIF)

An NJ tree for the PER2 intron sequences and the divergence times of the haplotypes with 1000 bootstrap replicates. The phased sequences that had homozygotes of three major haplotypes (Hap1, Hap2, and Hap3) in YRI, CEU, and JPT were obtained from the 1000 Genome Project (phase 3) database. The arrows represent divergence times. (TIF)

Comparison of the distributions of percentages of melatonin suppression for PER2 alleles of (A) SNP1, (B) SNP5, and (C) SNP6. The thick middle lines in the boxes represent the medians, and the tops and bottoms of the boxes represent the third and the first quartiles, respectively. One dot represents one chromosome, and the numbers of chromosomes, n...

Comparison of the distributions of (A) percentages of pupil constriction and (B) MEQ score for four major haplotypes of PER3. The thick middle lines in the boxes represent the medians, and the tops and bottoms of the boxes represent the third and the first quartiles, respectively. One dot represents one chromosome, and the numbers of chromosomes, n...

Haplotype frequencies for (A) PER2 and (B) PER3. The numbers of local populations included in the geographical region are shown in parentheses. N represents the numbers of the individuals. The combined frequencies of the remaining haplotype (Residuals) are less than 1.0% in all the geographical regions. (TIF)

Comparison of the distributions of (A) percentages of pupil constriction and (B) MEQ score for three major haplotypes of PER2. Thick middle lines in the boxes represent the medians, and the tops and bottoms of the boxes represent the third and the first quartiles, respectively. One dot represents one chromosome, and the numbers of chromosomes, n, a...

The intuitiveness of tangible user interface (TUI) is not only for its operator. It is quite possible that this type of user interface (UI) can also have an effect on the experience and learning of observers who are just watching the operator using it. To understand the possible effect of TUI, the present study focused on the mu rhythm suppression...

In the present study, we investigated the effect of the image of hands on mu rhythm suppression invoked by the observation of a series of tool-based actions in a goal-directed activity. The participants were 11 university students. As a source of visual stimuli to be used in the test, a video animation of the porcelain making process for museums wa...

Light is the strongest synchronizer of human circadian rhythms, and exposure to residential light at night reportedly causes a delay of circadian rhythms. The present study was conducted to investigate the association between color temperature of light at home and circadian phase of salivary melatonin in adults and children. Twenty healthy children...

Previous studies have demonstrated that a light-dark cycle has promoted better sleep development and weight gain in preterm infants than constant light or constant darkness. However, it was unknown whether brief light exposure at night for medical treatment and nursing care would compromise the benefits brought about by such a light-dark cycle. To...

We examined the effects of an exergame intervention on exercise performance, as well as the influence of players' personality traits on the effects of the intervention. In total, 16 elderly persons (>65 years old) participated in the study for 12 weeks. Participants were required to complete the Big Five Scale. We measured the number of times that...

Short-term interval timing i.e., perception and action relating to durations in the seconds range, has been suggested to display time-of-day as well as wake dependent fluctuations due to circadian and sleep-homeostatic changes to the rate at which an underlying pacemaker emits pulses; pertinent human data being relatively sparse and lacking in cons...

We examined the effect of sleep deprivation on self-motion perception (vection). We measured the strength of vection, its latency, and its duration in two conditions: Sleep-Deprivation and Normal-Sleep (by using the between-subject design). For the Sleep-Deprivation condition, participants did not sleep for about 20 hours. We also recorded subjecti...

The purpose of this study was to investigate the physiological and psychological effects of sit to stand exercise using a video game. Twelve young male adults performed sit to stand exercise with a video game and without a video game. Heart rate, oxygen consumption (VO2), electromyogram of lower limbs (%MVC) and perceived exertion (RPE) were measur...

Background Emotional information is frequently processed below the level of consciousness, where subcortical regions of the brain are thought to play an important role. In the absence of conscious visual experience, patients with visual cortex damage discriminate the valence of emotional expression. Even in healthy individuals, a subliminal mechani...

To assess circadian preference with a score, the Morningness-Eveningness Questionnaire (MEQ) has been used for more than 3 decades now. More recently, the Munich ChronoType Questionnaire (MCTQ) was developed: it asks for sleep-wake behavior on work and free days and uses the midpoint of sleep on free days (MSF), corrected for sleep debt accumulated...

Background In our previous studies, we found that the Ile394Thr SNP in the melanopsin gene (OPN4) was functionally associated with the pupillary light reflex. This indicates the possibility that OPN4*Ile394Thr is associated with other non-image forming responses. The aim of this study was therefore to determine whether OPN4*Ile394Thr is associated...

Evaluation of circadian phenotypes is crucial for understanding the pathophysiology of diseases associated with disturbed biological rhythms such as circadian rhythm sleep disorders (CRSDs). We measured clock gene expression in fibroblasts from individual subjects and observed circadian rhythms in the cells (in vitro rhythms). Period length of the...

Melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) play an important role in non-image forming responses to light, such as circadian photoentrainment, light-induced melatonin suppression, and pupillary light response. Although it is known that there are some single nucleotide polymorphisms (SNPs) in the melanopsin (O...

The results of neuroimaging studies have indicated that viewing emotional stimuli can lead to activity increases in brain regions associated with processing actions. We hypothesized that observation of actions involving the potential for harm (i.e., risk-taking actions) would activate emotion- and pain-related processing. We used functional magneti...

Background Some people can subconsciously wake up naturally (self-awakening) at a desired/planned time without external time stimuli. However, the underlying mechanism regulating this ability remains to be elucidated. This study sought to examine the relationship between hemodynamic changes in oxyhemoglobin (oxy-Hb) level in the prefrontal cortex a...

Background The purpose of the present study was to compare sinusoidal versus constant lower body negative pressure (LBNP) with reference to very mild whole-body heating. Sinusoidal LBNP has a periodic load component (PLC) and a constant load component (CLC) of orthostatic stress, whereas constant LBNP has only a CLC. We tested two sinusoidal patter...

Evaluating individual circadian rhythm traits is crucial for understanding the human biological clock system. The present study reports characterization of physiological and molecular parameters in 13 healthy male subjects under a constant routine condition, where interfering factors were kept to minimum. We measured hormonal secretion levels and e...

Emotional maturity and social awareness are important for adolescents, particularly college students beginning to face the challenges and risks of the adult world. However, there has been relatively little research into personality maturation and psychological development during late adolescence and the neural changes underlying this development. W...

Regions that demonstrate significant hemodynamic signal changes during the observation of risk-taking vs. safe actions. (DOC)