Biomedical subjects

Yukuo Konishi

Publications and source records attributed to Yukuo Konishi.

14 recordsLinked to original sources

PubMed2006

Auditory dominance in the error correction process: a synchronized tapping study.

The goal of this study was to reveal auditory dominance in the error correction process that operates in the synchronized tapping paradigm. We presented six female subjects with a sound and a flash, alternately and successively. The subjects' task was to tap in synchrony with the sequence of the attended to modality (the target sequence). The inter-onset interval of the target sequence was 996 ms but varied irregularly between 996 - alpha ms and 996 + alpha ms for the distractor sequence. We found that tapping accuracy was influenced by the irregularity of the distractor sequence. As distractor stimuli were temporally separated from target stimuli, auditory-visual integration in timing did not occur in our experiment. Therefore, the irregularity of the distractor sequence must have directly influenced the error correction process in timing and not indirectly by affecting the target sequence to subsequently influence the error correction process. We also found that tapping accuracy was influenced by the irregularity of the auditory distractor, even when the irregularity was unnoticeable, but it was not affected by the irregularity of the visual distractor when the irregularity was unnoticeable, which suggests that the error correction process is located before, or is independent of, the perception of irregularity in timing. We conclude that the error correction process depends more on temporal information from the auditory system than on information from the visual system.

Acoustic Stimulation↗

PubMed2006

[Development of auditory-visual spatial integration using saccadic response time as the index].

We measured saccadic response time (SRT) to investigate developmental changes related to spatially aligned or misaligned auditory and visual stimuli responses. We exposed 4-, 5-, and 11-month-old infants to ipsilateral or contralateral auditory-visual stimuli and monitored their eye movements using an electro-oculographic (EOG) system. The SRT analyses revealed four main results. First, saccades were triggered by visual stimuli but not always triggered by auditory stimuli. Second, SRTs became shorter as the children grew older. Third, SRTs for the ipsilateral and visual-only conditions were the same in all infants. Fourth, SRTs for the contralateral condition were longer than for the ipsilateral and visual-only conditions in 11-month-old infants but were the same for all three conditions in 4- and 5-month-old infants. These findings suggest that infants acquire the function of auditory-visual spatial integration underlying saccadic eye movement between the ages of 5 and 11 months. The dependency of SRTs on the spatial configuration of auditory and visual stimuli can be explained by cortical control of the superior colliculus. Our finding of no differences in SRTs between the ipsilateral and visual-only conditions suggests that there are multiple pathways for controlling the superior colliculus and that these pathways have different developmental time courses.

Acoustic Stimulation↗

PubMed2004

Developing the brain -- a proposal to pediatricians.

What we should do as pediatric neurologists to solve educational problems may be not only to find symptomatic solutions but also to drastically re-evaluate 'the view of children'. Brain science, rapidly advancing at present, gives us some new scientific achievements, such as neuronal cell death, synaptic overproduction/elimination, sensitive period, higher cortical function of neonates, and neural correlates, useful for this re-evaluation. From this aspect, I have made a proposal for the establishment of new developmental neurology.

Brain↗

PubMed2004

Learned audio-visual cross-modal associations in observed piano playing activate the left planum temporale. An fMRI study.

Lip reading is known to activate the planum temporale (PT), a brain region which may integrate visual and auditory information. To find out whether other types of learned audio-visual integration occur in the PT, we investigated "key-touch reading" using functional magnetic resonance imaging (fMRI). As well-trained pianists are able to identify pieces of music by watching the key-touching movements of the hands, we hypothesised that the visual information of observed sequential finger movements is transformed into the auditory modality during "key-touch reading" as is the case during lip reading. We therefore predicted activation of the PT during key-touch reading. Twenty-six healthy right-handed volunteers were recruited for fMRI. Of these, 7 subjects had never experienced piano training (naïve group), 10 had a little experience of piano playing (less trained group), and the remaining 9 had been trained for more than 8 years (well trained group). During task periods, subjects were required to view the bimanual hand movements of a piano player making key presses. During control periods, subjects viewed the same hands sliding from side to side without tapping movements of the fingers. No sound was provided. Sequences of key presses during task periods consisted of pieces of familiar music, unfamiliar music, or random sequences. Well-trained subjects were able to identify the familiar music, whereas less-trained subjects were not. The left PT of the well-trained subjects was equally activated by observation of familiar music, unfamiliar music, and random sequences. The naïve and less trained groups did not show activation of the left PT during any of the tasks. These results suggest that PT activation reflects a learned process. As the activation was elicited by viewing key pressing actions regardless of whether they constituted a piece of music, the PT may be involved in processes that occur prior to the identification of a piece of music, that is, mapping the complex sequence structure of hand movements onto the sequence of sounds.

Adolescent↗

PubMed2004

[New challenge for social activities in the Japanese Society of Child Neurology--establishment of Social Activity and Public Relations Committee: introductory remarks].

The Japanese Society of Child Neurology newly established Social Activity and Public Relations Committee for the purpose of flexible response to the social event publicity. The committee consists of more than 36 members and is divided into the following sub-committees: Sub-committee 1 is intended to support the management and care of patients with developmental disabilities from infancy to adolescence, Sub-committee 2 devoted to the acquisition of research grants and the communication of basic scientific research, and Sub-committee 3 to coordinate and support medical-educational relationship. These three sub-committees achieved many of their goals during their stated first year of existence.

Child↗

PubMed2004

[Current state of research funds and research facilities of the members of the Japanese Society of Child Neurology].

The state of research funds and research facilities was analyzed by a questionnaire sent to members of the Council of the Japanese Society of Child Neurology. Research funds were most frequently about 5 million yen, and only 10% of the responder received 10 million yen or more. Still, many of them replied that they were satisfied with their research funds. Research funds of the Japanese Society of Child Neurology are considered to be in a critical condition. Most of the responders wanted information about research funds and a campaign to raise them organized by the Society.

Child↗

PubMed2003

Brain imaging in awake infants by near-infrared optical topography.

Studies of young infants are critical to understand perceptual, motor, and cognitive processing in humans. However, brain mechanisms involved are poorly understood, because the use of brain-imaging methods such as functional magnetic resonance imaging in awake infants is difficult. In the present study we show functional brain imaging of awake infants viewing visual stimuli by means of multichannel near-infrared spectroscopy, a technique that permits a measurement of cerebral hemoglobin oxygenation in response to brain activation through the intact skull without subject constraint. We found that event-related increases in oxyhemoglobin were evident in localized areas of the occipital cortex of infants aged 2-4 months in response to a brief presentation of a checkerboard pattern reversal while they maintained fixation to attention-grabbing stimuli. The dynamic change in cerebral blood oxygenation was qualitatively similar to that observed in the adult brain. This result introduces near-infrared optical topography as a method for investigating the functional development of the brain in early infancy.

Brain↗

PubMed2003

Hemodynamic responses to visual stimulation in occipital and frontal cortex of newborn infants: a near-infrared optical topography study.

A near-infrared optical topography (OT) was used to reveal spatio-temporal changes in the cerebral oxygenation of newborn infants in response to brief visual stimulation. Newborn infants were presented 3-s stroboscopic light flashing at 14 Hz during spontaneous sleep. Event-related changes in oxy- and deoxyhemoglobin ([oxy-Hb] and [deoxy-Hb]) were observed over the occipital and frontal cortex. The visual stimulus produced statistically significant increases in oxyhemoglobin not only in the occipital cortex but also in the prefrontal cortex. These results suggest that the cerebrovascular coupling is already functioning in newborn's brain. The prefrontal activation implies that it may contribute to early processing of sensory signals.

Cerebrovascular Circulation↗

PubMed2003

[Developing the brain--proposal to child neurologists: how to nurture and stimulate brain development].

Infants achieve remarkable functions during the first year of life. Dendrites and synaptic connections grow and subcortical myclination takes place. In recent years, we have witnessed remarkable progress in the field of neuroscience. It has become clear that the human brain shows maximal plasticity in infancy and early childhood. This plasticity provides a golden window of opportunity to maximize human development. Excess synaptic connections are eliminated during late childhood, a phenomenon that appears to be influenced at least to some extent by the environment. In many years of clinical practice as a pediatrician, I have observed the growth and development of both normal children and those challenged with developmental disabilities. Parents need to spend time responding to and playing with their young children. The plasticity of the human brain in early life is not only an opportunity; it is also responsibility. We must provide all children with the optimal environment for both intellectual and psychological development. It seems that sensitive and sympathetic responses from caretakers are of critical importance. Physicians and basic investigators have the responsibility of further elucidating brain function, as means of discovering how to optimize the environment for development of the human brain.

Brain↗

PubMed2003

[Learning from baby].

With regards to education, there are various problems, which have repeatedly been investigated and discussed by many commissions and committees. The conclusions drawn from these efforts have, however, swung back and forth over time, like a pendulum. Apart from finding symptomatic solutions, pediatric neurologists in the 21st century should drastically re-evaluate "the view of children" by virtue of brain science that has been rapidly advancing. From this aspect, I would like to make a proposal for the establishment of new developmental neurology.

Child Development↗

PubMed2002

Functional brain imaging using fMRI and optical topography in infancy.

We performed functional magnetic resonance imaging and optical topography over the visual cortex of subjects during sedation with pentobarbital, and 8-Hz flickering light was intermittently projected onto their eyelids. Two age groups were analyzed: infants <60 days old and those >60 days old (corrected for gestational age at birth). The stimulus-related signal change was positive in the lateral geniculate nucleus regardless of the infant's age, but it reversed in the primary visual cortex from positive in the infants less than 60 days old to negative in the infants more than 60 days old (Experiment 1). We also investigated spontaneous changes in the cerebral oxygenation state of neonates and infants aged 1 month during quiet sleeping by using a form of multi-channel near-infrared spectroscopy: non-invasive optical topography. Spatially synchronized oscillations of changes in the concentration of oxy-hemoglobin (oxy-Hb) and deoxy-Hb were observed throughout the occipital cortex in neonates but not in the infants aged 1 month. Time series analysis based on the theory of non-linear oscillations showed that the mean periods of the oscillation for each infant ranged from 11 to 18s. The phase lag of oxy-Hb relative to deoxy-Hb was stable at about 3 pi/4 in neonates but in the infant aged 1 month, time lag was unstable. These findings may be due to rapid synaptogenesis in early life.

Journal Article↗

PubMed2002

The relationship between mismatch negativity and arousal level. Can mismatch negativity be an index for evaluating the arousal level in infants?

BACKGROUND: Electrophysiological and behavioral studies have shown that stimulus relevance contributes to auditory processing in sleep and auditory stimuli changes the sleep stages. So we observed changes in auditory processing due to sleep stages by recording infant mismatch negativity (MMN) during different states and investigated the arousal mechanisms. METHODS: Auditory event-related potentials (ERPs) of 26 neonates were recorded using high-density EGI EEG system. Stimuli consisted of 1000 Hz tones with 90% probability as standard and 1200 Hz with 10% probability as deviant. Study 1 was designed for the confirmation of the recording of MMN from neonates and Study 2 for investigating whether an appropriate stimulus onset asynchrony (SOA) of the stimulus would induce a clear difference in the latency or amplitude. RESULTS: (Study 1) MMN were obtained from all subjects. No differences of the latencies, amplitudes and distribution due to arousal or sleep stage were observed. After the MMN response occurred, a prominent negativity like Nc was seen in response to deviant stimuli in active sleep and waking state. (Study 2) No distinct differences between the difference states were seen in any SOA. CONCLUSIONS: Only MMN did not characterize the arousal or sleep stage. But the modality of the auditory evoked potentials (AEPs) may differ according to the state, so further detailed investigation could enable the detection of the infants' state using the AEP.

Journal Article↗

PubMed2002

Visual feature binding in early infancy.

How does the developing brain of the human infant solve the feature-binding problem when visual stimuli consisting of multiple colored objects are presented? A habituation--dishabituation procedure revealed that 1-month-old infants have the ability to discriminate changes in the conjunction of a familiar shape and color in two objects. However, this good earlier performance was followed by poorer performance at 2 months of age. The performance improved again at 3 months of age. Detailed analysis of the oculomotor behaviors revealed that the age of 2 months was a period of drastic transition when the tendency to stay with the fixated objects disappeared and repetitive saccades between the two objects emerged. Our findings suggest that the ability to perceive conjunctions of features is available to infants very early, that the perceptual/neural basis at 1 and at 3 months of age may be fundamentally different, and that feature integration by vigorous eye movements or selective attention may be the key functional difference between the age groups.

Analysis of Variance↗

PubMedDate not supplied

Age-dependent change in metabolic response to photic stimulation of the primary visual cortex in infants: functional magnetic resonance imaging study.

The blood oxygen level-dependent (BOLD) response to photic stimulation in the primary visual cortex (V1) reverses from positive to negative around 8 weeks of age. This phenomenon may be caused by increased oxygen consumption during stimulation as the result of a rapid increase of synaptic density at this age. To test this hypothesis, we applied existing mathematic models of BOLD signals to the experimental data from infants. When the stimulus-related increments of cerebral blood flow and cerebral blood volume were fixed at 60% and 20%, respectively, the mean estimated increment of the cerebral metabolic rate of oxygen of the V1 in the elder infant group (57.1% +/- 8.8%) was twice as large as that in the younger infant group (32.2% +/- 4.7%), which corresponds to the reported difference in synaptic density. The present data confirmed that a change in oxygen consumption could explain a transition from a positive to a negative BOLD response.

Age Factors↗