Rosalind Franklin University Cell Biology & Anatomy Professor's Results On Neural Plasticity

The Chicago
Medical School (CMS) of the Rosalind Franklin University of Medicine and
Science (RFUMS) today announced that Assistant Professor of Cell Biology &
Anatomy, Athanasios Tzounopoulos, has uncovered novel forms of synaptic
plasticity that occur at the very first step in the processing of sound in
the central nervous system. His findings are being released today in
Neuron, one of two leading journals in Neuroscience.


"The ability to observe synaptic plasticity and uncover its cellular
mechanisms at such an early, relatively unprocessed stage allows us to
study the role of these mechanisms in sensory processing," said Professor
Tzounopoulos. "Our findings also show that the brain is able to change
itself as a result of previous experience at places where processing is
much simpler and better understood. This new capability could have a
significant impact on our understanding and cures for disorders caused by
neural plasticity-like mechanisms," he added.



These findings may be relevant for understanding the mechanisms of
human tinnitus. Tinnitus is the perception of ringing, buzzing, roaring, or
other noises in the ears or head - when there is no external source of the
noise. It is estimated that more than 50 million Americans experience
tinnitus to some degree. Of these, about 12 million have tinnitus severe
enough to seek medical attention. Many learn to ignore the sounds and
experience no major effects. However, about two million patients are so
seriously debilitated that they cannot function normally, finding it
difficult to hear, work or sleep. Though research is providing more
evidence for the causes and treatments of tinnitus, there is no real
understanding of the biological bases of tinnitus, nor are there any
treatments that help most sufferers. Recent studies point to the central
nervous system as the site for the maintenance of tinnitus. Moreover,
animal models of tinnitus indicate a role for the dorsal cochlear nucleus
(DCN, an auditory brainstem nucleus), the brain area where Professor
Tzounopoulos performed his studies.



"It is quite possible that transient exposure to intense sound might
induce long-term changes in the balance of excitation and inhibition in the
DCN, through the mechanisms described in our recent findings. Our studies,
by providing a detailed understanding on how this plasticity is induced,
expressed, and modulated at the cellular level may ultimately lead to
treatments for tinnitus," said Professor Tzounopoulos.



According to these recent findings, newly formed hypotheses suggest
that concerted operation of different forms of synaptic plasticity gate
sensory activation of the DCN and can lead to activity-dependent modulation
of timing precision. Timing is an important feature in the brain and
especially in the auditory system. Many neurons in the auditory system are
known for their ability to fire action potentials that occur in a precise
temporal relationship to the stimulus (phase locking). Activity-dependent
modulation of spike timing precision through these mechanisms is a new
concept that may allow sensory systems to adapt to different patterns of
sensory activity and to properly integrate and encode varying sensory
stimuli.
















Recent studies have shown that more robust and faithful brainstem
timing encoding is observed in trained individuals (musicians) compared to
untrained individuals (non-musicians). While these types of learning
phenomena have been attributed to cortical plasticity until now, our
studies suggest that the brainstem itself has the mechanisms and the
capability to support such learning. Similar studies have established that
brainstem timing precision serves as a reliable marker of individuals with
learning disabilities. Faulty mechanisms of neural timing at the brainstem
may be the biological basis of malfunction in children with learning
disabilities. "Therefore, elucidation of mechanisms underlying synaptic
plasticity and timing precision in the brainstem may provide the cellular
basis for these learning disabilities," said Professor Tzounopoulos.



Rosalind Franklin University of Medicine and Science educates medical
doctors, health professionals, and biomedical scientists in a personalized
atmosphere. The University is located at 3333 Green Bay Road, North
Chicago, IL 60064, and encompasses Chicago Medical School, College of
Health Professions, Dr. William M. Scholl College of Podiatric Medicine,
and School of Graduate and Postdoctoral Studies. Visit us at
rosalindfranklin and lifeindiscovery.


Rosalind Franklin University of Medicine and Science

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