Biomedical subjects

Yukuo Konishi

Publications and source records attributed to Yukuo Konishi.

5 recordsLinked to original sources

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

[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

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↗