NNS 2015 Program & Abstract Book

Philadelphia VA Medical Center, Neurosurgery, Philadelphia, USA

University of Pennsylvania, Pharmacology, Philadelphia, USA

University of Pennsylvania, Biology, Philadelphia, USA

The electrophysiological and morphological phenotyping of human

neurons was performed on resected cortical and hippocampal tissue

from cases of Communicating Hydrocephalus, Epilepsy, Normal

Pressure Hydrocephalus and brain tumor. A clinical history of trau-

matic brain injury (TBI) was present in a number of these cases. The

differences in electrophysiological properties of adult human neurons

are being correlated to the single-cell analysis of the mRNA tran-

scriptome. With IRB approval 73 patients were enrolled with in-

formed consent, with several having a history of TBI (age 25–86). A

case report form was populated with the subject information, which

includes cortical location of the tissue, past medical history and pa-

thology report. Brain tissue that is otherwise discarded was collected

into ice-cold oxygenated artificial cerebrospinal solution to preserve

the cortical circuitry components. We developed a methodology to

electrophysiologically characterize neurons from both acute brain

slices and primary neuronal cultures. Spontaneous and induced action

potentials as well as concurrent field potentials were recorded from

350 um thick cortical and hippocampal slices using intracellular sharp

electrodes filled with potassium acetate. Dissociated adult human

neurons survived in culture for over 6 weeks. In order to electro-

physiologically characterize cultured neurons, whole-cell currents and

action potentials were recorded using patch-clamp technique, and

intrinsic membrane properties such as input resistance and membrane

potential were analyzed. Sequencing of the transcriptome for a subset

of these neurons is in process, and will allow for correlation of the

variability in the electrophysiological properties with mRNA ex-

pression. In order to develop a better understanding of the variability

of the mRNA profile of individual cells, as well as in various disease

states, identified correlations will be compared between TBI and non-

TBI cases.

Keywords: TBI, adult human neurons, electrophysiology, single

cell mRNA analysis

C6-04

TIME-COURSE PROFILE OF EEG ABNORMALITY DE-

TECTED BY QEEG POWER SPECTRAL ANALYSIS FOL-

LOWING A SINGLE CONCUSSIVE BRAIN INJURY IN RATS

Xi-Chun May Lu

, Ying Cao, Zhinlin Liao, Frank Tortella, Deborah

Shear

Walter Reed Army Institute of Research, Brain Trauma Neuropro-

tection & Neurorestoration/Psychiatry and Neuroscience, Silver

Spring, USA

Quantitative EEG (qEEG) is a sensitive measure of cerebral func-

tional changes following brain injury. In this study we applied qEEG

power spectral analysis to examine EEG power shifts caused by a

mild concussive brain injury. Rats received a single projectile con-

cussive impact (PCI) injury aimed at the right dorsal surface of the

brain, or sham procedures, immediately followed by bilateral EEG

electrode implantation and continuous EEG monitoring for 14 days.

The qEEG power spectral analysis was performed at 6, 12, 18, 24, 48,

72h, 7, and 14 days post-injury. The EEG global frequency band was

divided into standard delta, theta, alpha, beta, and gamma bands. The

relative EEG power of each band was expressed as the percent of the

total power of the global band. Spectral power analysis revealed that

moderate but significant EEG slowing occurred as early as 6h post

injury in the ipsilateral hemisphere, which persisted for at least 24h as

evidenced by a significant increase in EEG delta power (p

0.05 vs.

sham at each time point). Similar trends in EEG slowing, albeit to a

lesser degree, were measured between 48 and 72h post PCI (p

0.05),

followed by the restoration of normal EEG activities by the 7

day

post PCI which remained stable thereafter. EEG slowing in the con-

tralateral hemisphere was manifested in a delayed and more transient

fashion, with mirrored increases in the delta activity only at 18 and

24h post PCI without the subsequent tapering phenomenon observed

in the ipsilateral hemisphere. In summary, the demonstration of EEG

slowing in the rat model of mild concussive brain injury provides a

functional brain injury marker which can be used along with other

biological and behavioral measures to better understand the patho-

logical mechanisms of concussive brain injury.

Keywords: EEG Power Spectrum Analysis, Projectile Concussive

Impact Brain Injury, Rats

C7 Poster Session VI - Group C: Inflammation

C7-01

MORPHOLOGY ALONE DOES NOT DEFINE THE RANGE

OF MICROGLIAL PHENOTYPES AFTER DIFFUSE BRAIN

INJURY

Jenna Ziebell

1,2

, Jack Reddaway

1–3

, Gayatri Sadachar

1,2

, Jonathan

Lifshitz

1,2

Barrow Neurological Institute at Phoenix Children’s Hospital, Child

Health, Phoenix, USA

University of Arizona, Child Health, Phoenix, USA

University of Bath, Biology and Biochemistry, Bath, UK

Microglial activity affects neurological function. Ramified microglia

represent a naı¨ve state; whereas activated microglia, in varying pro-

portions of morphologies, indicate states of disease. Identifying cel-

lular markers associated with each microglial morphology may more

precisely define microglial function. Here, we demonstrate that mor-

phologically similar microglia do not necessarily have similar patterns

of cellular markers. Adult male Sprague-Dawley rats were subjected

to midline fluid percussion sham or brain-injury. Brain tissue was

collected at 2h, 1d, 2d, 7d, 28d and 56d post-injury. To characterize

the phenotype of microglia, immunohistochemical double-labelling

was undertaken with Iba1 in conjunction with CD45, CD68 (ED1),

CD11b, or Ox6 (MHCII). Analysis concentrated on the sensorimotor

cortex. Iba1 positive ramified microglia did not show reactivity to

CD45 or CD68. Injury-induced microglial activation included Iba1-

positive activated, amoeboid and rod microglia. When amoeboid

microglia were present, they were reactive for CD45, however no

other morphology reacted with this marker. For CD68, no microglial

morphology showed reactivity at 2h post-injury. By 1d post-injury,

some activated and amoeboid microglia showed reactivity, but rod

microglia did not. At 7d, in addition to activated and amoeboid mi-

croglia, some but not all, rod microglia showed CD68 reactivity. By

28d post-injury, CD68 reactivity had increased predominantly in ac-

tivated and amoeboid microglia. Furthermore, Ox6 was present in

some, but not all, activated and rod microglia at 7d. Intriguingly, not

all rod microglia reacted to Ox6 despite these cells appearing to be

coupled. These data indicate an over simplification in relying on

morphology for microglial activation state. Studies inevitably need to

combine morphology and cytokine receptor levels to more accurately

phenotype microglia, for which specific functions have yet to be as-

cribed. Moreover, precision medicine could manipulate microglial

phenotypes to restore neurological function. Partially supported by

NIH NINDS R01NS065052 and PCH Mission Support Funds.

Keywords: Microglia, Diffuse brain injury, Immunohistochemistry

A-86