Changes in cortical activity in the OBiden model of multiple

sclerosisKate Van Pelt

CMMG SURP 2016Gow Lab

What is multiple sclerosis (MS)?

• MS is classically thought to be an immune-mediated demyelinating disorder of the central nervous system (CNS)

• Estimated to effect around 2.5 million patients worldwide • MS is highly variable and manifests in a host of physical,

neurological, and psychiatric symptoms• Characterized by:

• White matter lesions – Motor impairment• Gray matter lesions – Deficits in memory and cognition

(Mayo Clni, 2015)

The OBiden model• A primary white matter pathology MS model• Pathology induced weekly throughout lifespan

beginning at 2 months• OBiden mice show evidence of a depression-like

endophenotype from 6-12 months• At 12 months, OBiden mice demonstrate

impairments in learning and memory

Electroencephalography (EEGs)

• EEGs record electrical activity from the brain

• Clinical EEGs in MS patients suggest a relationship between cognitive impairment in MS and abnormal EEG activity compared to healthy controls (Leocani et al., 2001)

• Waves of interest:• Delta (0-5 Hz)• Theta (5-12 Hz)

•EEGs measure:• Power• Coherence

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Interhemispheric coherence• A measure of coupling

between frequency spectra originating from separate channels

• 0 - 1.0 scale• Used as an indication of

functional association between two brain regions (Thatcher et al., 2004)

• Interhemispheric coherence: measures degree of association between the two hemispheres

coherence

coherence↓

↑

Decreased coherence at 12 months in OBiden mice

Relative power at 12 months

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OBiden mice have normal coherence at 6 months

Relative power at 6 months

Conclusions• Clinical EEGs of MS patients report decreases in

interhemispheric coherence in the theta band compared to healthy controls (Leocani et al., 2001)

• Compared to 12 months, 6 month OBiden mice do not demonstrate significant differences in interhemispheric coherence

• OBiden mice show impairment at 12 months in learning and memory tasks correlated with a dropout of theta band coherence

• These findings suggest that the electrophysiological pathology documented at 12 months arises between the 6-month and 12-month time points

AcknowledgementsPI: Dr. Alexander Gow

Lab Members:Dr. Kathleen Maheras Cherie SouthwoodChelsea R. RichardsonDaniel Z. Radecki