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HOME >> Profile
of Norihiro Sadato
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Education |
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| 1977-1979 |
Premedical Course, Faculty of Medicine,
Kyoto University |
| 1979-1983 |
Medical Course, Faculty of Medicine, Kyoto University
(Degree: MD) |
| 1990-1994 |
Postgraduate School (Internal Medicine), Kyoto University
(Degree: PhD) |
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Positions and
Employment |
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| 1983-1985 |
Resident, Medicine, Tenri Hospital, Nara,
Japan |
| 1985-1988 |
Resident, Department of Radiology, Tenri
Hospital, Nara, Japan |
| 1988-1990 |
Staff, Department of Radiology, Tenri
Hospital, Nara, Japan |
| 1988-1990 |
Clinical Fellow, Department of Neuroradiology,
University of Maryland Medical System, Baltimore, Maryland,
USA |
| 1993-1995 |
Visiting Fellow, Human Motor Control
Section, NINDS, NIH, Bethesda, USA |
| 1995 |
Assistant Professor, Department of Radiology,
Fukui Medical School, Fukui, Japan |
| 1995-1998 |
Lecturer, Biomedical Imaging Research
Center, Fukui Medical School |
| 1998 |
Associate Professor, Biomedical Imaging
Research Center, Fukui Medical School |
| 1999-present |
Professor, Section of Cerebral Integration,
Division of Cerebral Research, National Institute for
Physiological Sciences, Okazaki, Japan |
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Certification |
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| 1983 |
National Medical Practitioner’s, Japan |
| 1991 |
Japanese Board of Radiology |
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Other Experience
and Professional Memberships |
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| 1985-present |
Japanese Society of Radiology |
| 1990-present |
Japanese Society of Nuclear Medicine |
| 1990-present |
Society of Nuclear Medicine (USA) |
| 1994-present |
American Academy of Neurology (Associate) |
| 1994-present |
Society for Neuroscience (USA) |
| 1995-present |
Japanese Society for Neuroscience |
| 1997-present |
International Society of Cerebral Blood
Flow and Metabolism |
| 1998-present |
Japanese Society of Magnetic Resonance |
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Honors |
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| 1995 |
NIH 1995 Fellows Award for Research Excellence |
| 1998 |
1998 The 36th Award
of the Japanese Society of Nuclear Medicine |
| 1999 |
1999 1998 Giovanni Di Chiro Award for Outstanding
Scientific Research |
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List of
10 major publications |
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| 1. |
Sadato, N., Zeffiro, T.A., Campbell,
G., Konishi, J., Shibasaki, H. and Hallett, M.
Regional cerebral blood flow changes in motor cortical areas after
transient anesthesia of the forearm.
Ann Neurol, 1995. 37: p. 74-81. |
| 2. |
Okazawa, H., Naito, Y., Yonekura, Y., Sadato, N.,
Hirano, S., Nishizawa, S., Magata, Y., Ishizu, K.,
Tamaki, N., Honjo, I. and Konishi, J.
Cochlear implant efficiency in pre- and postlingual deafness A study
with  and
PET.
Brain, 1996. 119: p. 1297-1306. |
| 3. |
Sadato, N., Pascual-Leone, A., Grafman, J., Ibanez,
V., Deiber, M.-P., Dold, G. and Hallett, M.
Activation of the primary visual cortex by Braille reading in blind
subjects.
Nature, 1996. 380: p. 526-528. |
| 4. |
Cohen, L.G., Celnik, P., Pascual-Leone, A., Corwell,
B., Faiz, L., Dambrosia, J., Honda, M., Sadato, N.,
Gerloff, C., Catala, M.D. and Hallett, M.
Functional relevance of cross-modal plasticity in blind humans.
Nature, 1997. 389: p. 180-183. |
| 5. |
Yamada, H., Sadato, N., Konishi, Y., Kimura, K.,
Tanaka, M., Yonekura, Y. and Ishii, Y.
A rapid brain metabolic change in infants detected by fMRI.
NeuroReport, 1997. 8: p. 3775-3778. |
| 6. |
Sadato, N., Pascual-Leone, A., Grafman, J., Deiber,
M.P., Ibanez, V. and Hallett, M.
Neural networks for Braille reading by the blind.
Brain, 1998. 121(Pt 7): p. 1213-29. |
| 7. |
Morita, T., Kochiyama, T., Yamada, H., Konishi, Y.,
Yonekura, Y., Matsumura, M. and Sadato, N.
Difference in the metabolic response to photic stimulation of the
lateral geniculate nucleus and the primary visual cortex of infants:
a fMRI study.
Neurosci Res, 2000. 38: p. 63-70. |
| 8. |
Sadato, N., Ibanez, V., Deiber, M.-P. and Hallett,
M.
Gender difference in premotor activity during active tactile discrimination.
Neuroimage, 2000. 5: p. 532-40. |
| 9. |
Yamada, H., Sadato, N., Konishi, Y., Muramoto, S.,
Kimura, K., Tanaka, M., Yonekura, Y., Ishii, Y. and
Itoh, H.
A milestone for normal development of the infantile brain detected
by functional MRI.
Neurology, 2000. 55(2): p. 218-23. |
| 10. |
Sadato, N., Okada, T., Honda, M. and Yonekura, Y.
Critical period for cross-modal plasticity in blind humans: a functional
MRI study.
Neuroimage, 2002. 16: p. 389-400. |
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Description
of the main scientific contribution |
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1. Studies about cross-modal plasticity in
the blind: Activation of the visual cortex of the blind during
tactile discrimination.
Primary visual cortex receives visual input from the eyes, but
is not known to receive input from other sensory modalities.
To determine whether the visual cortex receives input from the
somatosensory system, Sadato et al. (1996, 1998) used positron
emission tomography (PET) to measure activation during tactile
discrimination tasks in normal subjects and in Braille readers
blinded in early life (before 14 y.o.). Blind subjects showed
activation of primary and secondary visual cortical areas during
tactile tasks, whereas normal controls showed deactivation.
A simple tactile stimulus that did not require discrimination
produced no activation of visual areas in either group. Thus
in blind subjects, cortical areas normally reserved for vision
may be activated by other sensory modalities.
The age dependency of this remarkable reorganization was investigated
by fMRI (Sadato et al. 2002). Blind subjects, irrespective of
the age at onset of blindness, exhibited higher activity in
the visual association cortex than did sighted subjects. V1
was activated in blind subjects who lost their sight before
16 years of age, whereas it was suppressed in blind subjects
who lost their sight after 16 years of age during a tactile
discrimination task. This suggests that the first 16 years of
life represent a critical period for a functional shift of V1
from processing visual stimuli to processing tactile stimuli.
To address the functional relevance of the visual cortices of
the blind during tactile task, transcranial magnetic stimulation
was utilized (Cohen et al. 1997, 1999) to disrupt the function
of different cortical areas in people who were blind from an
early age as they identified Braille or embossed Roman letters.
Transient stimulation of the occipital (visual) cortex induced
errors in both tasks and distorted the tactile perceptions of
early blind, but not late blind subjects. In contrast, occipital
stimulation had no effect on tactile performance in normal-sighted
subjects. Taken together with the neuroimaging studies they
conclude that blindness from an early age (before 15 y.o.) can
cause the primary visual cortex to be recruited to a role in
somatosensory processing.
2. Functional neuroimaging studies of babies
During development, the brain produces a vast excess of neurons,
synapses, and dendritic spines as part of the maturational process.
An age-related changes in synaptic density has been determined
in the human primary visual cortex: rapid synapse production
starts postnatally at the age of 2 months. To depict developmental
changes of activity-related metabolism in human visual cortex,
functional magnetic resonance imaging (fMRI) from the neonatal
period was performed (Yamada, et al. 1997, 1999). A rapid metabolic
changing pattern accompanying normal human brain maturation
was revealed by fMRI with photic stimulation. Infants older
than 8 weeks of age showed a stimulus-related signal decrease
in the visual cortex, whereas younger neonates showed a signal
increase. This inversion of response was not observed in the
lateral geniculate nucleus which synaptogenesis is completed
before delivery (Morita, et al. 2000). It is also independent
of the white matter maturation (Yamada, et al. 1999). Hence
inversion of the response suggests a change in oxygen consumption
during neuronal activation, which is related to rapid synapse
formation and accompanying increased metabolism. fMRI can detect
dynamic metabolic changes during the brain maturation, and provides
a new clue in the detection of abnormal brain development or
central nervous system plasticity.
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