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symptoms, visual acuity, eye alignment, near point of convergence,
vergence amplitude/facility, accommodative amplitude/facility, and
saccadic eye movement speed and accuracy.
72 children were examined with a mean age of 14.6 years. 49/72
(68%) had one or more vision problems. The most common problems
were convergence insufficiency (47.2%), accommodative insuffi-
ciency (33.3%), saccadic dysfunction (30.5%), and accommodative
infacility (11.1%). 64% with convergence insufficiency also had an
accommodative disorder. The Convergence Insufficiency Symptom
Survey (CISS) was used to assess visual symptoms. The mean CISS
score for children without a vision problem was 13.2 vs. 21.4 in
children diagnosed with significant vision problems (p
=
0.001). There
was no significant difference in the prevalence of vision problems
when comparing recent (
<
3 months) vs. longstanding (
>
3 months)
concussion injury. Patients with a vision problem also had deficits in
verbal memory and visual motor scores on computerized neurocog-
nitive testing (p
=
0.016 and p
=
0.0074).
A high prevalence of oculomotor disorders (binocular vision, ac-
commodative, and eye movement) was found in this sample of ado-
lescents with concussion. These results suggest that a vision
examination that specifically evaluates oculomotor function should be
a part of the evaluation of concussion.
Children may be particularly vulnerable to the consequences of
such deficits after concussion due to their full-time academic work at
school.
Keywords: vision, vestibular, oculomotor, concussion
PL01 New Investigators and New Visions for CNS
Iinjury Research
PL01-01
ENHANCING RESPIRATORY PLASTICITY FOLLOWING
CERVICAL SPINAL CORD INJURY
Michael Lane
, Lyandasha Zholudeva, Kristiina Negron, Timothy
Whelan, Tatiana Bezdudnaya, Victoria Spruance
Drexel University, Neurobiology, Philadelphia, USA
Impaired breathing is a devastating consequence of cervical spinal
cord injury (SCI), representing a significant burden to injured people
and increasing the risk of mortality. This is due in part to the direct
compromise of the phrenic motor system that controls diaphragm
function. While there is mounting evidence for spontaneous im-
provements in phrenic function and respiration, the extent of re-
covery – or functional plasticity – remains limited. The neuroplastic
changes contributing to this recovery remain a subject of ongoing
research. However, recent experimental studies suggest that spinal
interneurons contribute to phrenic plasticity and represent a thera-
peutic target for enhancing functional recovery post-SCI. Capita-
lizing on the potential of these cells, the goal of the present work is
to test whether transplantation of interneuron-rich neural precursor
tissue can restore anatomical continuity, contribute to formation of
novel interneuronal relays, and enhance diaphragm recovery.
Adult, female Sprague Dawley rats received lateralized C3/4 con-
tusion injuries and were allowed to recover for 1 week. At that time,
the injury site is re-exposed and allogeneic donor tissue (from de-
veloping rat spinal cord) was transplanted directly into the lesion
epicenter. Ventilation was assessed using whole-body plethysmogra-
phy weekly pre- and post-injury. One month post-injury, transneur-
onal tracing was then used to examine the extent of synaptic
integration between i) host and donor neurons, and ii) transplanted
cells and host phrenic circuitry. One month post-transplantation, ter-
minal neurophysiological studies were used to assess phrenic func-
tion, and record activity from transplanted neurons.
These experiments revealed that transplanted cells survive, prolif-
erate, restore tissue continuity and become synaptically integrated
with host phrenic circuitry. Host neurons also become integrated with
donor cells. Terminal electrophysiology has shown improvement in
phrenic function in transplant recipients. Multiunit recordings made
from within transplanted tissue have revealed phasic patterns of ac-
tivity consistent with inspiration. These results suggest that trans-
plantation of neural progenitor tissue from the developing spinal cord
may contribute to an interneuronal relay capable of improving dia-
phragm recovery following cervical SCI.
Keywords: spinal cord injury, phrenic, interneuron, neural precur-
sor, respiration
PL01-02
RNA SPLICING IN CNS DAMAGE: DIAGNOSING THE IN-
JURED SPLICEOSOME
Travis Jackson
University of Pittsburgh, Critical Care Medicine, Pittsburgh, USA
Most mammalian genes encode one or more mRNA transcripts which
give rise to multiple protein variants having altered or opposing biological
function. Acute brain injury or progressive neurodegenerative disease
disrupts spliceosomes – sites of active RNA splicing in the nucleus.
Different protein splicing factors (SFs), which modulate variant selection
of distinct gene sets, are also disturbed by injury. Aberrant SF balance
could favor translation of detrimental protein variants. Characterizing the
functions of enigmatic SFs in brain, including identification of their un-
ique mRNA targets, may yield new insights into molecular sequelae
causing neuronal dysfunction after injury. SFs may also represent novel
therapeutic targets – inhibiting or activating key SFs could be used to
correct splicing perturbations caused by damage. Here we focus discus-
sion of this topic on the splicing factor RNA Binding Motif 5 (RBM5),
and in the setting of experimental TBI. In brain, nuclear RBM5 mostly
localizes to neurons, and this finding is supported by
in vitro
evidence.
After combined control cortical impact (CCI)
+
hemorrhagic shock (HS)
in mice, RBM5 appears upregulated throughout the ipsilateral hippo-
campus and cortex. Findings here expand understandings of splicing
dysregulation after TBI and offer new concepts for future therapies.
Keywords: RNA Splicing, RNA Binding Motif 5, Controlled
Cortical Impact, Hemorrhagic Shock
PL01-03
PLASTICITY IN THE CORTICOSPINAL SYSTEM AFTER
SPINAL CORD INJURY
Monica Perez
University of Miami, Neurological Surgery, Miami, USA
The corticospinal tract is an important target for motor recovery
after spinal cord injury (SCI) in animals and humans. Using non-
invasive electrophysiological techniques we have demonstrated the
presence of plasticity in corticospinal projections targeting spinal
motoneurons of muscles located close and at a long distance from
the injury site in humans with chronic anatomically incomplete
cervical SCI. We developed tailored protocols for precisely timing
the arrival of descending and peripheral volleys at corticospinal-
motoneuronal synapses of hand muscle in humans with chronic in-
complete SCI. We found that the arrival of presynaptic volleys prior
to motoneuron discharge enhanced corticospinal transmission and
hand voluntary motor output. These findings are the first demon-
A-130