Negative BOLD responses during hand and foot movements: An fMRI study.

The present study employed functional magnetic resonance imaging (fMRI) to examine the characteristics of negative blood oxygen level-dependent (Negative BOLD) signals during motor execution. Subjects repeated extension and flexion of one of the following: the right hand, left hand, right ankle, or left ankle. Negative BOLD responses during hand movements were observed in the ipsilateral hemisphere of the hand primary sensorimotor area (SMI), medial frontal gyrus (MeFG), middle frontal gyrus (MFG), and superior frontal gyrus (SFG). Negative BOLD responses during foot movements were also noted in the bilateral hand SMI, MeFG, MFG, SFG, inferior frontal gyrus, middle temporal gyrus, parahippocampal gyrus, anterior cingulate cortex, cingulate gyrus (CG), fusiform gyrus, and precuneus. A conjunction analysis showed that portions of the MeFG and CG involving similar regions to those of the default mode network were commonly deactivated during voluntary movements of the right/left hand or foot. The present results suggest that three mechanisms are involved in the Negative BOLD responses observed during voluntary movements: (1) transcallosal inhibition from the contralateral to ipsilateral hemisphere in the SMI, (2) the deactivated neural network with several brain regions, and (3) the default mode network in the MeFG and CG.

Illusory Motion Reproduced by Deep Neural Networks Trained for Prediction.

The cerebral cortex predicts visual motion to adapt human behavior to surrounding objects moving in real time. Although the underlying mechanisms are still unknown, predictive coding is one of the leading theories. Predictive coding assumes that the brain's internal models (which are acquired through learning) predict the visual world at all times and that errors between the prediction and the actual sensory input further refine the internal models. In the past year, deep neural networks based on predictive coding were reported for a video prediction machine called PredNet. If the theory substantially reproduces the visual information processing of the cerebral cortex, then PredNet can be expected to represent the human visual perception of motion. In this study, PredNet was trained with natural scene videos of the self-motion of the viewer, and the motion prediction ability of the obtained computer model was verified using unlearned videos. We found that the computer model accurately predicted the magnitude and direction of motion of a rotating propeller in unlearned videos. Surprisingly, it also represented the rotational motion for illusion images that were not moving physically, much like human visual perception. While the trained network accurately reproduced the direction of illusory rotation, it did not detect motion components in negative control pictures wherein people do not perceive illusory motion. This research supports the exciting idea that the mechanism assumed by the predictive coding theory is one of basis of motion illusion generation. Using sensory illusions as indicators of human perception, deep neural networks are expected to contribute significantly to the development of brain research.

Effects of mastication on human somatosensory processing: A study using somatosensory-evoked potentials.

The aim of the present study was to investigate the effects of mastication on somatosensory processing using somatosensory-evoked potentials (SEPs). Fourteen healthy subjects received a median nerve stimulation at the right wrist under two conditions: Mastication and Control. SEPs were recorded in five sessions for approximately seven minutes: Pre, Post 1, 2, 3, and 4. Subjects were asked to chew gum for five minutes after one session in Mastication. Control included the same five sessions. The amplitudes and latencies of P14, N20, P25, N35, P45, and N60 components at C3', frontal N30 component at Fz, and P100 and N140 components at Pz were analyzed. The amplitude of P45-N60 was significantly smaller at Post 1, 2, 3, and 4 than at Pre in Control, but not in Mastication. The latency of P25 was significantly longer at Post 2, 3, and 4 than at Pre in Control, but not in Mastication. The latency of P100 was significantly longer at Post 2 than at Pre in Control, but not in Mastication. These results suggest the significant effects of mastication on the neural activity of human somatosensory processing.

Temporal dynamics of neural activity in motor execution and inhibition processing.

Although many neuroimaging studies using functional magnetic resonance imaging have shown the neuronal networks for motor execution and inhibition processing, the precise activation timing of each brain region is not yet well understood. In the present study, we investigated the temporal dynamics of neural activities in multiple brain regions using magnetoencephalography (MEG) and electroencephalography (EEG) simultaneously during somatosensory Go/No-go paradigms. The results of MEG showed that neural activities in the bilateral premotor area at approximately 150 ms and in the primary motor cortex at approximately 250 ms were only detected in Go trials, while brain responses in the bilateral prefrontal cortex at approximately 170 ms were only observed in No-go trials. In addition, the amplitudes of the N140 and P300 components in EEG was significantly larger in No-go trials than in Go trials, and the latencies of N140 and P300 were significantly later in No-go trials than in Go trials. Our results indicated the time courses of neural processing in response execution and inhibition processing, and revealed differences in their underlying neural mechanisms.

Effects of task repetition on event-related potentials in somatosensory Go/No-go paradigm.

We investigated the effects of task repetition on the N140 and P300 components of event-related potentials (ERPs) in somatosensory Go/No-go paradigms. A Go or No-go stimulus was presented to the second or fifth digit of the left hand, respectively, at the same probability, and subjects had to respond by pushing a button with their right thumb as quickly as possible only after the presentation of a Go stimulus. The condition comprised seven sessions of recordings, and subjects were allowed to relax for five minutes after one session. The behavioral data for the reaction time (RT), standard deviation of RT, and error rates showed the absence of an effect by task repetition. In ERP waveforms, the amplitudes of N140 and P300 decreased with task repetition, and the latency of P300 was delayed by task repetition. There was no significant effect of task repetition on the peak latency of N140. Changes in amplitude and latency values in N140 and P300 during Go/No-go paradigms reflected changes in the neural activation of response execution and inhibition processing with task repetition.

Mastication accelerates Go/No-go decisional processing: An event-related potential study.

OBJECTIVE: The purpose of the present study was to investigate the effect of mastication on Go/No-go decisional processing using event-related potentials (ERPs). METHOD: Thirteen normal subjects underwent seven sessions of a somatosensory Go/No-go paradigm for approximately 4min; Pre, and Post 1, 2, 3, 4, 5, and 6. The Control condition included the same seven sessions. The RT and standard deviation were recorded, and the peak amplitude and latency of the N140 and P300 components were analyzed. RESULTS: The RT was significantly shorter in Mastication than in Control at Post 1-3 and 4-6. The peak latency of N140 was earlier in Mastication than in Control at Post 4-6. The latency of N140 was shortened by repeated sessions in Mastication, but not by those in Control. The peak latency of P300 was significantly shorter in Mastication than in Control at Post 4-6. The peak latency of P300 was significantly longer in Control with repeated sessions, but not in Mastication. CONCLUSIONS: These results suggest that mastication may influence response execution processing in Go trials, as well as response inhibition processing in No-go trials. SIGNIFICANCE: Mastication accelerated Go/No-go decisional processing in the human brain.

Somato-motor inhibitory processing in humans: evidence from neurophysiology and neuroimaging.

Motor execution processing has been examined using an index of behavioral performance such as reaction times, kinetics, and kinematics. However, difficulties have been associated with the study of motor inhibitory processing because of the absence of actual behavioral performance. Therefore, non-invasive neurophysiological and neuroimaging methods including electroencephalography, magnetoencephalography, transcranial magnetic stimulation, and functional magnetic resonance imaging have been used to investigate neural processes in the central nervous system. We mainly reviewed research on somato-motor inhibitory processing based on data obtained by using these techniques, which can examine 'when', 'where, and 'how' motor inhibition occurs in the brain. Although to date a number of studies have used these techniques separately, few studies have utilized them in a comprehensive manner. In this review, we provide evidence that combining neurophysiological and neuroimaging methods should contribute to our understanding of how executive and inhibitory functions are implemented.

Meditation reduces pain-related neural activity in the anterior cingulate cortex, insula, secondary somatosensory cortex, and thalamus.

Recent studies have shown that meditation inhibits or relieves pain perception. To clarify the underlying mechanisms for this phenomenon, neuroimaging methods, such as functional magnetic resonance imaging, and neurophysiological methods, such as magnetoencephalography and electroencephalography, have been used. However, it has been difficult to interpret the results, because there is some paradoxical evidence. For example, some studies reported increased neural responses to pain stimulation during meditation in the anterior cingulate cortex (ACC) and insula, whereas others showed a decrease in these regions. There have been inconsistent findings to date. Moreover, in general, since the activities of the ACC and insula are correlated with pain perception, the increase in neural activities during meditation would be related to the enhancement of pain perception rather than its reduction. These contradictions might directly contribute to the 'mystery of meditation.' In this review, we presented previous findings for brain regions during meditation and the anatomical changes that occurred in the brain with long-term meditation training. We then discussed the findings of previous studies that examined pain-related neural activity during meditation. We also described the brain mechanisms responsible for pain relief during meditation, and possible reasons for paradoxical evidence among previous studies. By thoroughly overviewing previous findings, we hypothesized that meditation reduces pain-related neural activity in the ACC, insula, secondary somatosensory cortex, and thalamus. We suggest that the characteristics of the modulation of this activity may depend on the kind of meditation and/or number of years of experience of meditation, which were associated with paradoxical findings among previous studies that investigated pain-related neural activities during meditation.

Relationship between performance variables and baseball ability in youth baseball players.

The present study investigated the relationship of performance variables and anthropometric measurements on baseball ability in 164 youth baseball players (age: 6.4-15.7 years). To evaluate their baseball performance, ball speeds in pitching and batting were recorded and kinetic energies of the pitched and hit balls were calculated. To record anthropometric and physical fitness characteristics, height and weight were measured and a battery of physical fitness tests covering standing long jump, side steps, sit-ups, 10-m sprint, trunk flexion, back strength, and grip strengths of both hands were conducted. The results of a multiple regression analysis revealed several significant predictors: age, body mass index (BMI), standing long jump, 10-m sprint, and grip strength for pitched ball kinetic energy and age, BMI, standing long jump, and back strength for hit ball kinetic energy. This study provides scientific evidence that relates certain specific physical performance tests and body characteristics with high achievement in the actual performance of pitching and batting. Youth players, their parents, coaches, and trainers would benefit by addressing these characteristics when planning training programs to improve the baseball performance of youth players.

Relative age effects in Japanese baseball: an historical analysis.

The present study investigated the existence of the relative age effect, a biased distribution of birth dates, in Japanese professional baseball players born from 1911 to 1980. Japan applies a unique annual-age grouping for sport and education, which is from April 1 to March 31 of the following year. Thus, athletes were divided into four groups based on their month of birth; quarters Q1 (April-June), Q2 (July-September), Q3 (October-December), and Q4 (January-March of the following year). There were statistically biased distributions of birth dates among players born in the 1940s and subsequent decades (medium effects), and similar (but small) relative age effects were observed among players born in the 1910s, 1920s, and 1930s. The magnitude of the relative age effect changed with time, and socio-cultural factors such as international competition and media coverage may have contributed greatly to this effect.

Cortical rhythm of No-go processing in humans: an MEG study.

OBJECTIVE: We investigated the characteristics of cortical rhythmic activity in No-go processing during somatosensory Go/No-go paradigms, by using magnetoencephalography (MEG). METHODS: Twelve normal subjects performed a warning stimulus (S1) - imperative stimulus (S2) task with Go/No-go paradigms. The recordings were conducted in three conditions. In Condition 1, the Go stimulus was delivered to the second digit, and the No-go stimulus to the fifth digit. The participants responded by pushing a button with their right thumb for the Go stimulus. In Condition 2, the Go and No-go stimuli were reversed. Condition 3 was the resting control. RESULTS: A rebound in amplitude was recorded in the No-go trials for theta, alpha, and beta activity, peaking at 600-900 ms. A suppression of amplitude was recorded in Go and No-go trials for alpha activity, peaking at 300-600 ms, and in Go and No-go trials for beta activity, peaking at 200-300 ms. CONCLUSION: The cortical rhythmic activity clearly has several dissociated components relating to different motor functions, including response inhibition, execution, and decision-making. SIGNIFICANCE: The present study revealed the characteristics of cortical rhythmic activity in No-go processing.

Association of relative age effects in sports with number of years in school.

The present study investigated the association of the relative age effect, a biased distribution of birth dates, with a high school versus university background in Japanese professional soccer and baseball players. The number of athletes born in the first quarter (April-June) was larger than the number born in the fourth quarter (January-March) for both soccer and baseball; however, the magnitude of the relative age effect differed with years in school. The skew of birth dates was stronger among players who only graduated high school than those who graduated university or college. This phenomenon was confirmed in both baseball and soccer players. The findings suggest relative age effects in professional sports to be related to years of age and years in school.

Sex differences in relative age effects among Japanese athletes.

The present study investigated the relative age effect (RAE), a biased distribution of elite athletes' birthdates, in Japanese female athletes. Japan applies a unique annual-age grouping for sport and education, which is from April 1 to March 31 of the following year. A total of 1,335 female athletes were evaluated from six sports: softball, soccer, volleyball, basketball, badminton, and track and field (long distance), and compared with male athletes. All athletes played in the top level of Japanese leagues for each sport in 2010. Distribution of the birth dates in each female sport showed a significant RAE only in volleyball. For males, significant RAEs were observed in baseball, soccer, and track and field. Findings suggest that the determinants of RAEs in sports may differ between males and females.

Diffuse central hypomyelination presenting as 4H syndrome caused by compound heterozygous mutations in POLR3A encoding the catalytic subunit of polymerase III.

We describe a 33-year-old male patient with mental retardation and cerebellar ataxia whose brain magnetic resonance imaging (MRI) showed diffuse central hypomyelination. The associated hypogonadotropic hypogonadism and hypodontia were consistent with the clinical diagnosis of 4H syndrome. Two compound heterozygous mutations in POLR3A were found: p.Met852Val and p.Asn1249His. MRI of the brain showed cerebellar atrophy, atrophy of the corpus callosum, and diffuse hypomyelination extending as far as the U-fibers, with preservation of the basal ganglia. T2 hyperintensity was observed in the bilateral middle cerebellar peduncles. The patient showed almost normal development until 4-5years of age. After 25years of age, the patient showed a gradual but consistent motor and cognitive deterioration. We demonstrated the involvement of the corticospinal tract electrophysiologically, but peripheral nerve conduction was normal. Although this disease may start very early in life, the clinical course in the present case suggests that brains that initially appear to have developed normally may show dysfunction later in life, although the pathophysiological bases for this dysfunction may not be evident on MRIs.

The relationship between reaction time and response variability and somatosensory No-go potentials.

We investigated the relationship between reaction time (RT) and response variability and somatosensory Go/No-go potentials. Event-related potentials following electrical stimulation of the second (Go stimulus) or fifth (No-go stimulus) digit of the left hand were recorded from 16 subjects, and Go and No-go stimuli were presented at an even probability. The subjects were instructed to respond to the Go stimuli by pushing a button with their right thumb. We analyzed the correlation between RT and the N140 and P300 components, and between the standard deviation (SD) of RT and the N140 and P300. Neither the amplitude nor latency of the No-go-N140 (N140 evoked by No-go stimuli) or the Go-N140 (N140 evoked by Go stimuli) related significantly with RT and the SD of RT. There was a significant negative correlation between RT and the amplitude of the No-go-P300 (P300 evoked by No-go stimuli) at Fz and C3, indicating that subjects with a shorter RT had a No-go-P300 of larger amplitude. The latency of the Go-P300 (P300 evoked by Go stimuli) at Pz and C3 showed a significant correlation with RT. The SD of RT was significantly correlated with the amplitudes of the No-go-P300 at C3 and Go-P300 at Pz and C4, and the latency of the No-go-P300 at Cz and Go-P300 at Fz, Cz, Pz, C3, and C4. Our results suggest that response speed and variability for the Go stimulus in Go/No-go paradigms affect No-go-related neural activity for the No-go stimulus.

Relative age effect in Japanese male athletes.

The present study investigated the relative age effect, a biased distribution of elite athletes' birthdates, in Japanese male athletes. Japan applies a unique annual-age grouping for sport and education, which is from April 1 to March 31 of the following year. A total of 4,318 male athletes was evaluated from 12 sports: baseball, soccer, basketball, volleyball, handball, golf, horse racing, rugby, American football, sumo, Ekiden (track and field in long distance), and badminton. They played in the top level of Japanese leagues for each sport in 2010. The distribution of the birth dates was examined in each sport and showed significant relative age effect in baseball, soccer, volleyball, Ekiden, basketball, sumo, and horse racing, but not in all sports. The findings suggest that although the school year in Japan starts on April 1, significant relative age effects are observed in some sporting events.

The relationship in gating effects between short-latency and long-latency somatosensory-evoked potentials.

We investigated the relationship between short-latency and long-latency somatosensory-evoked potentials (SEPs) relating to voluntary movement. In general, the amplitudes of short-latency components in SEPs are attenuated during movement, whereas those of long-latency are enhanced, and this phenomenon is termed 'gating effects'. This study aimed to examine the relationship of changes in amplitude between short-latency and long-latency SEPs. SEPs were recorded from 11 participants at Fz, Cz, Pz, and C4' by stimulating the left median nerve. Two tasks were conducted; Control and Movement. In Control, the participant was asked to relax with no specific task. In Movement, the participant was encouraged to continue a rapid drumming motion of all fingers of the left hand at a self-paced rate. The amplitudes of short-latency SEPs, the P25 at C4' and N30 at Fz, were significantly smaller in the Movement than Control condition. By contrast, the amplitudes of long-latency SEPs, the N140 at Fz, Cz, and Pz were significantly larger in Movement than Control condition. Moreover, a significant positive correlation was observed in the rate of amplitude change between the frontal N30 and vertex N140, indicating that for the participants with a frontal N30 of smaller amplitude during Movement, the amplitude of the vertex N140 was smaller. We inferred that the neural activities in movement-related cortices affected the sources for the frontal N30 and vertex N140 in the same neuronal network simultaneously.

Effects of the interstimulus interval on somatosensory go/no-go event-related potentials.

This study investigated the characteristics of event-related potentials using somatosensory go/no-go paradigms. We manipulated the interstimulus interval and analyzed its effect on the peak amplitude and latency of the N140 and P300 components. The amplitude of N140 increased as the interstimulus interval increased, and was significantly larger in no-go than in go trials at the 1-s and 2-s interstimulus intervals, but not the 4-s and 6-s interstimulus intervals. The amplitude of P300 also increased with the interstimulus interval, and was significantly larger in no-go than in go trials at all interstimulus intervals. The reaction time in go trials was longer with increasing interstimulus interval. This study suggests that brain activities associated with go/no-go decisional processes are influenced by the interstimulus interval.

Characteristics of No-go-P300 component during somatosensory Go/No-go paradigms.

The present study investigated one of the characteristics of No-go-related brain activity during somatosensory Go/No-go paradigms, by manipulating the stimulus site and response hand. Somatosensory event-related potentials (ERPs) were recorded in ten right-handed subjects. Electrical stimulation was delivered to the second and fifth digit of one hand, and the subjects had to respond to a Go stimulus by pushing a button with the thumb contralateral to the stimulated side as quickly as possible. We focused on the peak amplitude and latency of Som-Go-P300 (P300 evoked by somatosensory Go stimuli) and Som-No-go-P300 (P300 evoked by somatosensory No-go stimuli) components. The amplitude of Som-No-go-P300, which is very similar to No-go-P300 components following visual and auditory stimulation, was significantly larger than that of Som-Go-P300 at fronto-central electrodes, indicating 'anteriorization' of the No-go-P300. The amplitude of Som-No-go-P300 was significantly larger in right than left hemispheres during right hand response conditions, but this difference was not found under left hand conditions. In addition, the difference in amplitude between Som-Go- and Som-No-go-P300, which is frequently described as 'the Go/No-go effect' on P300, was significant in the left hemisphere under right hand response conditions, whereas a significant effect was found in both the left and the right hemispheres under left hand response conditions. Our findings suggested that the anteriorization of No-go-P300 was independent of stimulus modalities such as visual, auditory, and somatosensory, and the amplitude of No-go-P300 and Go/No-go effects on P300 was affected by the response hand.

A difference exists in somatosensory processing between the anterior and posterior parts of the tongue.

The somatic sensation of the tongue is necessary for daily life, but it is difficult to know the underlying neural mechanisms. In particular, because of the vomiting reflex and several morphological problems, no neuroimaging studies have examined somatosensory processing by stimulating the posterior part of the tongue, except for two magnetoencephalographic studies (Sakamoto et al., 2008a,b). This is the first study to clarify the human cortical processing for sensory perception by the posterior part of the tongue with a newly developed device and functional magnetic resonance imaging (fMRI). Stimulation of the left and right postero-lateral parts of the tongue induced significant activity in the primary somatosensory cortex (SI) and Brodmann area 40 in the right hemisphere and the anterior cingulate cortex (ACC). In contrast, antero-lateral stimulation produced activity only in the right SI. The activated region in SI was significantly larger following stimulation of the posterior than anterior part. These results indicate that a clear difference exists in somatosensory processing between stimulation of the antero-lateral and postero-lateral parts of the tongue, and a right hemisphere is dominant for the stimulation of both antero-lateral and postero-lateral areas. The activity in BA 40 and ACC may imply that the posterior of the tongue belongs to the visceral system.