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Neuroscience is a field of biology aimed at
understanding the functions of the brain at every
level, from molecular up to the behavior. In the
brain, nerve cell or neuron is the primary
functional unit, which communicates each other
through a unique structure called synapse—a
specialized connecting junction between neurons.
Synapse releases neurotransmitters to affect
function of other cells or a brain region. Neurons
modify their properties under the influence of their
input signals. This plasticity underlies
learning/memory or neurological diseases.
The research
in my lab is directed toward studying how neurons
communicate with each other, how the
communication is modified by experiences, and how the
brain function is altered by diseases such as stroke
or
epilepsy.
Current research programs:
Stroke: A stroke occurs
when the blood supply to part of the brain is
suddenly interrupted or when a blood vessel in the
brain bursts, spilling blood into the spaces
surrounding brain cells. Brain cells die when they
no longer receive oxygen and nutrients from the
blood or there is sudden bleeding into or around the
brain. We study the mechanisms of stroke and the
process of brain damage that results from stroke,
and, essentially, are working to develop new and
better ways to help the brain repair itself to
restore important functions.
Epilepsy: Epilepsy is a brain disorder in
which clusters of nerve cells, or neurons, in the
brain sometimes signal abnormally. In epilepsy, the
normal pattern of neuronal activity becomes
disturbed, causing strange sensations, emotions, and
behavior or sometimes convulsions, muscle spasms,
and loss of consciousness. Epilepsy may
develop because of an abnormality in brain wiring,
an imbalance of nerve signaling chemicals called
neurotransmitters, or some combination of these
factors. We study how neurotransmitters interact
with brain cells to control nerve firing in the
brain contribute to seizures, with goal of enhancing
treatment for epilepsy.
Learning & Memory: We study the
synaptic plasticity and long-lasting enhancement in
signal transmission and strength between neurons. A
phenomenon called long-term potentiation (LTP) is
widely considered on of the major cellular
mechanisms that underlies learning and memory. We
study the mechanism of LTP and the implication of
LTP in the brain disorders.
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Ongoing research is focused on the role of zinc (Zn2+)
as a signaling messenger, which represents a new
challenge of research and a new school of thought on
the brain function. Our overall hypotheses are
that zinc plays active roles in synaptic transmission
and in intracellular signaling. Zinc is packed
in many selected synapses. We demonstrate that this synaptic
zinc can be released as a new type of
neurotransmitter, and that zinc is required for the
induction of LTP, a model of learning/memory
formation. Thousands proteins/enzymes have
zinc binding sites; in fact, zinc is required for
proper function, as an activator, of many of them. The
mystery of zinc homeostasis is starting to be
unraveled through the efforts by zinc biologists or zincologists. We have identified the intracellular
sites of zinc storages, which is a critical step
toward understanding zinc stability in cell. We
demonstrate that rising zinc in the condition of
hypoxic-ischemic stress is a casual factor of cell
death. These observations support that zinc acts as
an intrinsic factor of signaling pathways.
Why Zinc?
Macro-view: Zinc is an essential
micronutrient and a vital component of
enzymes/proteins. There is spectrum of health
concerns to deregulation of zinc homeostasis in the
brain. Acute human dietary deficiency is accompanied
with zinc reversible neuronal symptoms: anorexia,
smell and taste dysfunction, emotional and cognitive
disturbances, and loss of coordination. Possibly,
the special pool of zinc involved in neuronal
signaling is preferentially affected. Chronic zinc
deficiency causes memory loss and mental
retardation. Zinc deficiency has been a major
etiological factor in the syndrome of "adolescent
nutritional dwarfism" that affects millions peoples.
Zinc deregulation (or zinc overload) has also been
implicated in the stroke, epileptic seizure, brain
traumas, and Alzheimer's disease (see
our publications). Association of
zinc with Wilson's disease, bone mineral density,
and diabetes has also been studied.
Micro-view: There is increasing evidence for
the involvement of this metal ion at all levels of
function within cells; as catalysts, structural
elements and possibly as second messengers. Zinc is
essential for normal cellular function such as gene
expression and enzymatic reactions as zinc finger
motif. Catalytic zinc sites are common in membrane
and lumen proteins. Zinc may serves an additional
signaling role in the brain by its interaction with
membrane receptors and intracellular signaling
pathways, including its actions in NMDA, GABA,
glycine or ATP receptors, and calcium, K+
channels; calmodulin mediated pathways. Zinc-induced
apoptosis or rising intracellular zinc can trigger a
destructive cycle (see
our publications). Yet, mystery
of how zinc homeostasis is maintained or regulated
is an appealing challenge and, ultimately, a
promising research opportunity. |
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“Men ought to know that from nothing
else but the brain come joys, delights, laughter and
sports, and sorrows, griefs, despondency, and
lamentations. And by this, in an special manner, we
acquire wisdom and knowledge, and see and hear, and
know what are foul and what are fair, what are bad
and what are good, what are sweet and what
unsavory....And by the same organ we become mad and
delirious, and fears and terrors assail us.... All
these things we endure from the brain, when it is
not healthy.....In these way I am of the opinion
that the brain exercise the greatest power in the
man”
Hippocrates, on the
Sacred Disease (Fourth century B.C.)
"The last
frontier of the biological sciences-their ultimate
challenge-is to understand the biological basis of
consciousness and the mental processes by which we
perceive, act, learn, and remember."
<Principles of Neural
Science>
"It is our
nature to be curious about how we see and hear; why
some things feel good and others hurt; how we move;
how we reason, learn, remember, and forget; the
nature of anger and madness. These mysteries are
starting to be unraveled by basic neuroscience
research."
<Neuroscience--Exploring
the Brain>
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