Page 84 - Q. Neuroscience

[Q. Neuroscience-51]

Repetitive head injury alters olfactory-associated

electroencephalographic, behavioral and pathological

sequelae in mice

Younghyun Yoon¹˙²˙#, YunHee Seol¹˙#, Hyoenjoo Im¹, Hyun Soo Shim¹, Hio-Been Han¹˙³, Jeongeun Kum¹˙⁴,

Jee Hyun Choi¹˙⁴˙*, Hoon Ryu¹˙⁵˙*

¹Center for Neuroscience, Korea Institute of Science and Technology, Seoul 02792, ROK, ²Department of Electrical

Engineering and Computer Science, Vanderbilt University, Nashville 37235, USA, ³Program of Brain and Cognitive
Engineering, Korea Institute of Science and Technology, Daejeon 34141, ROK, ⁴Department of Neuroscience,
Division of Bio-Medical Science & Technology, Seoul 02792, ROK, ⁵Boston University Alzheimer’s Disease Center

and Department of Neurology, Boston University School of Medicine, Boston 02130, USA

A series of repeated mild traumatic brain injury (TBI) by collision sports or accidents lead to long-term cognitive

impairments with an increased risk for neurodegenerative and psychiatric disorders. Olfactory dysfunction has been
observed as one of the most prominent symptoms in TBI patients, but the exact pathological mechanism is not

fully understood. In this present study, we investigated the acute effects of repetitive TBI on olfactory functioning
and its pathological neuronal injuries using a TBI mouse model that mimics concussions in humans.

Electroencephalography (EEG) neural impairments were observed in the olfactory bulb. Modulation index values for
delta-phase were significantly attenuated in fast oscillations in concussed mice and cross-frequency couplings

between delta phase and beta/low gamma amplitude were also significantly reduced. Through pathological
examination, we found a significant increase in p-Tau (S202/T205) in olfactory bulb-associated areas. Furthermore,
neuronal atrophy was correlated with p-Tau level. Lastly, TBI mice showed for an abnormal loss of preference in

home bedding under Y-maze conditions compared to controls. Together, p-Tau alterations may serve as important

biomarkers of olfactory track-associated dysfunctions and behavioral impairments