PDF File - Mahidol University

350
Abstracts
patterns of behavior, interests, and activities. MRI studies in
autism have found a variety of alterations including a
decrease of size of various brain structures. In functional
neuroimaging studies such as functional MRI (fMRI),
magnetic resonance spectroscopy (MRS), positron emission
spectroscopy (PET) and single photon emission computed
tomography (SPECT), various abnormalities have been
reported. SPECT has found a decrease of regional cerebral
blood flow (rCBF) in the frontal and temporal regions and the
left cerebral hemisphere, and has shown the relationship
between rCBF and symptoms. PET has found metabolic
abnormalities in frontal monoaminergic neuron systems,
and a decrease of glucose metabolic activity in anterior
cingulate gyrus. MRS has found energy metabolism abnormality
in the frontal lobe using 31P-MRS, and abnormality in
medial temporal and lateral frontal regions using 1 H-MRS.
fMRI has found a lower activity in the amygdala during face
recognition test and in the right fusiform gyrus during face
discrimination test. These structural and functional imaging
findings suggest that the anatomic abnormalities are multiple
and not located, and are more likely to be the results of
abnormal development of connections of undefined
disturbed neural networks for complex information processing
involving the frontal cerebral cortex, limbic system, and
posterior fosse brain structures. In this presentation,
previously reported findings will be discussed in relations
with possible mechanism of symptom occurrence in autism.
TU-5B
ADHD: current concepts and neurobiology
M. Denckla
The Kennedy Krieger Institute, Baltimore, MD, USA
Aided by advances in cognitive neuroscience and neuroimaging,
the emerging current concept of ADHD is that it
represents a group of deficits in self-control; affected in
some combination are motor control, cognitive control, and
emotional control. So frequent is the comorbidity with
ADHD of Developmental Motor Coordination Disorder
that this combination mirrors Gillberg’s DAMP syndrome.
Neuroimaging implicates parallel underlying circuits
comprised of frontal, striatal, and cerebellar regions, with
consensus based on MRI measurements that somewhat smaller
total brain volumes (3–5% reductions) are of multifocal
(not diffuse) origin, mostly small frontal and striatal hypoplasia.
This topic update on ADHD will also review diagnosis,
behavioral genetics, prognosis (especially genderdiscrepant),
neurotransmitters (with implications for genetics
and pharmacotherapeutics) and non-pharmacological
therapies. The emphasis, however, will be on the following:
implications of motor localization clues; neurocognitive
elucidation that attention allocation (not attention per se) is
deficient; and evidence from in vivo MR neuroimaging, both
anatomic MRI and fMRI, that frontal-striatal-cerebellar
circuits deserve scrutiny in relation to ADHD.
SYMPOSIUM
SY-1
Pathogenesis and Prevention of Prenatal and Perinatal
Brain Damage
SY-01-1
Structural and functional studies on cadherins, synaptic
adhesion molecules
W. Shan, D.R. Colman
Fishberg Research Center for Neurobiology, The Mount
Sinai School of Medicine, New York, New York, USA
The ability of the mammalian CNS to perform complex
informative processes and highly cognitive functions is
based on the precise and specifically determined connectivity
of different neuronal cell types at synapses. Recently studies
implicate that cadherins, calcium-dependent cell adhesion
molecules, are involved in synaptic formation, specifying
connections among different synapses and functional modulation
during early development. The molecular mechanisms
by which the classic cadherin mediate adhesion are beginning
to be elucidated. We have identified certain key residues
at the interface of N-cadherin molecules that participate in
cell-cell adhesion formation. In addition, two different, but
conserved cadherins are highly likely to form hetero-interaction
at adherent junction sites, which may increase the
diversity of synaptic connections. Furthermore, synaptic
modulation could be activated in either physiological or
pathological conditions, indicating a role for cadherins in
synaptic plasticity. Taken together, our data provide insights
into the mechanisms of formation of adherens junctions,
synaptic targeting, and modulation of synaptic activity.
SY-01-2
Basic mechanisms and prevention of prenatal brain
damage
P. Evrard
Service de Neurologie Pediatrique et des Maladies Metaboliques,
Faculte de Medicine Xavier-Bichat, Hospital
Robert-Debre, Paris, France
Abstract not submitted
SY-01-3
Neurophysilogical analysis of periventricular
leukomalacia in preterm infants
A. Okumura, K. Watanabe, F. Hayakawa, T. Kato
Department of Pediatrics, Nagoya University Graduate
School of Medicine, Nagoya, Japan
PVL is an important cause of cerebral palsy in preterm
infants. Serial EEG recordings are not only of great prognostic
value but also useful to determine the timing of brain