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conditions were equally and significantly impaired 6 weeks post injury
in comparison with the no-mTBI (p
<
0.001 and p
<
0.03 respectively)
and the mTBI
+
EE groups (p
<
0.001 for the 30 g, and p
<
0.017 for the
50 g). No differences were found between the control and the EE mice.
Two separate finding emerge: (1) the significantly positive effects of the
placement in EE following mTBI, on the rehabilitative process of the
tested behaviors in the affected mice; (2) the lack of difference between
the groups of mice affected by 30 gr or by 50 gr. Further studies are
needed in order to characterize the exact pathways involved in the
positive effects of the EE on mice recovery from mTBI. Possible
clinical implications indicate the importance of adapting correlates of
EE to humans, i.e., prolonged and intensive physical activity – possibly
combined with juggling training and intensive cognitive stimulation.
Keywords: Enriched Environment, Novel Object Recognition, Y
maze, mice
C1-08
TRAUMATIC BRAIN INJURY CORRELATES IN A VUL-
NERABLY HOUSED POPULATION
William Panenka
1
, Toby Schmitt
1
, Fidel Vila-Rodriguez
1
, Talia
Vertinsky
3
, Wayne Su
1
, Kristina Gigas
2
, William MacEwan
1
, Allen
Thornton
2
, William Honer
1
, Donna Lang
3
, Alexander Rauscher
3
1
University of British Columbia, Psychiatry, Vancouver, Canada
2
Simon Fraser University, Psychology, Burnaby, Canada
3
University of British Columbia, Radiology, Vancouver, Canada
Background:
Marginally housed or homeless populations have ele-
vated rates of medical and psychiatric illness, and may have a higher
rate of traumatic brain injury (TBI). TBI may act to predispose,
trigger, or perpetuate many other adverse health issues.
Objective:
To describe the frequency and severity of TBI in a sample
of marginally house individuals resident in Vancouver’s downtown
single room occupancy (SRO) hotels, and to characterize the relationship
between TBI and multiple health parameters in this population.
Methods:
A prospective community sample of 297 individuals was
evaluated at baseline with psychiatric and neurological assessments,
cognitive testing and multimodal MRI.
Results:
185 of 297 subjects (62%) endorsed a previous history of
any serious face of head injury. 37% (108) of subjects endorsed TBI
as defined by loss of consciousness or confusion after the head trauma,
and 81.7% of these were males. Assault was the most common
mechanism (41%) followed by falls (14%). The distribution of mild,
moderate, and severe TBI was 33%, 27%, and 19% respectively, and
we were unable to accurately determine severity in 21%. Magnetic
Resonance Imaging showed significant encephalomalacia consistent
with head trauma in 15 subjects (5% of the total sample). Compared to
subject with no history of TBI, those with TBI reported more dizzi-
ness and fainting (p
=
0.001), seizures (p
=
0.031), and memory com-
plaints (p
=
0.02). In addition, subjects with TBI were more likely to
have a history of alcohol dependence (p
=
0.012), a diagnosis of bi-
polar I disorder (p
=
0.047) and to have been charged with a criminal
offense (p
=
0.014). There were no differences on neuropsychological
testing between the groups.
Conclusions:
Individuals in marginalized housing have a high rate
of TBI and trauma related findings on cranial MRI. Neuropsychiatric
correlations of TBI in this group include dizziness, fainting, memory
problems, seizures, alcohol dependence, bipolar disorder and crimi-
nality. These findings suggest that specialized acquired brain injury
services may benefit vulnerably housed individuals.
Keywords: Traumatic Brain Injury, homeless, marginalized hous-
ing, Psychiatry
C1-09
CONTROLLED CORTICAL IMPACT INCREASES COCAINE
INTAKE IN RATS: A POTENTIAL ROLE FOR NEUROIN-
FLAMMATION IN ADDICTION
Cole Vonder Haar
1
1
University of British Columbia, Psychology, Vancouver, Canada
2
University of California - San Francisco, Physical Therapy and
Rehabilitation Science, San Francisco, USA
Recent clinical evidence has begun to show relationships between
traumatic brain injury (TBI) and numerous psychiatric disorders. One
large concern put forth by clinicians is the possibility that TBI and
drug addiction may be linked. However, it is difficult to elucidate
causation of this relationship in clinical settings due to the complex
history of individuals. In the current study, we combined a well-
established rat model of TBI and addiction in order to determine if brain
injury increased risk for addiction. Rats were given a bilateral controlled
cortical impact over the frontal cortex at either severe (3m/s, 2.5 mm
depth) or milder (1 m/s, 0.8 mm depth) settings or a sham procedure.
After one week, rats underwent a second surgery to implant a catheter
into the jugular vein. A week later, they were placed in operant
chambers to self-administer IV infusions of cocaine (0.5 mg/kg/infu-
sion) or saline for 6 hours/day over a 10 day period. Rats were eu-
thanized at day 25 post-injury and cortical samples collected to
measure inflammatory markers via multiplex ELISA. All cocaine-
treated rats pressed the lever more and received more infusions than
saline rats regardless of injury. Brain-injured rats (both severe and
mild) pressed more for cocaine and received more infusions than
sham rats. Severe-injured rats were slower to discriminate the active
lever from the inactive lever. Levels of multiple inflammatory cyto-
kines were increased as a result of cocaine intake and TBI. A principal
components analysis revealed general patterns of change as a result of
cocaine self-administration and TBI with cocaine intake increasing
inflammatory cytokines in sham animals, but decreasing these mark-
ers in injured animals. These novel data demonstrate a causal link
between TBI and addiction and suggests that proinflammatory cyto-
kines may be responsible for this effect. Increases in neuroin-
flammation following brain injury may resemble processes found in
cocaine addiction that predispose individuals to the addictive effects
of drugs.
Keywords: Addiction, Cytokine, Controlled cortical impact, Co-
caine, Self-Administration
C1-10
STIMULUS-SPECIFIC ENHANCED CONTEXTUAL FEAR
LEARNING FOLLOWING LATERAL FLUID PERCUSSION
EXPERIMENTAL TRAUMATIC BRAIN INJURY
Ann Hoffman
1,2
, Jamie Lam
2
, Yan Cai
1
, David Hovda
1
, Christopher
Giza
1
, Michael Fanselow
2
1
UCLA, Neurosurgery; Brain Injury Research Center, Los Angeles,
USA
2
UCLA, Psychology, Los Angeles, USA
Traumatic brain injury (TBI) is a silent epidemic and is labeled the
signature injury of troops in OIF/OEF combat operations, a population
that are often exposed to stressful stimuli and emotional trauma.
While TBI is typically known to impair learning and memory for
neutral events, traumatic fear memories are enhanced after TBI,
consistent with increased prevalence of comorbid TBI and post-
traumatic stress disorder (PTSD). Changes in sensitivity to sensory
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