MEG Working Memory N-Back Task Reveals Functional Deficits in Combat-Related Mild Traumatic Brain Injury

Ming-Xiong Huang; Sharon Nichols; Ashley Robb-Swan; Annemarie Angeles-Quinto; Deborah L Harrington; Angela Drake; Charles W Huang; Tao Song; Mithun Diwakar; Victoria B Risbrough; Scott Matthews; Royce Clifford; Chung-Kuan Cheng; Jeffrey W Huang; Anusha Sinha; Kate A Yurgil; Zhengwei Ji; Imanuel Lerman; Roland R Lee; Dewleen G Baker

doi:10.1093/cercor/bhy075

MEG Working Memory N-Back Task Reveals Functional Deficits in Combat-Related Mild Traumatic Brain Injury

Cereb Cortex. 2019 May 1;29(5):1953-1968. doi: 10.1093/cercor/bhy075.

Authors

Ming-Xiong Huang^{1

2}, Sharon Nichols³, Ashley Robb-Swan², Annemarie Angeles-Quinto², Deborah L Harrington^{1

2}, Angela Drake⁴, Charles W Huang⁵, Tao Song², Mithun Diwakar⁶, Victoria B Risbrough^{1

7

8}, Scott Matthews⁹, Royce Clifford^{1

7

8}, Chung-Kuan Cheng¹⁰, Jeffrey W Huang¹¹, Anusha Sinha¹², Kate A Yurgil^{1

8

13}, Zhengwei Ji², Imanuel Lerman¹, Roland R Lee^{1

2}, Dewleen G Baker^{1

7

8}

Affiliations

¹ Radiology, Research, and Psychiatry Services, VA San Diego Healthcare System, San Diego, CA, USA.
² Department of Radiology, University of California, San Diego, CA, USA.
³ Department of Neuroscience, University of California, San Diego, CA, USA.
⁴ Cedar Sinai Medical Group Chronic Pain Program, Beverly Hills, CA, USA.
⁵ Department of Bioengineering, University of California, San Diego, CA, USA.
⁶ Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA.
⁷ Department of Psychiatry, University of California, San Diego, CA, USA.
⁸ VA Center of Excellence for Stress and Mental Health, San Diego, CA, USA.
⁹ ASPIRE Center, VASDHS Residential Rehabilitation Treatment Program, San Diego, CA, USA.
¹⁰ Department of Computer Science and Engineering, University of California, San Diego, CA, USA.
¹¹ Columbia University, New York, NY, USA.
¹² California Institute of Technology, Pasadena, CA, USA.
¹³ Loyola University New Orleans, LA, USA.

PMID: 29668852
DOI: 10.1093/cercor/bhy075

Abstract

Combat-related mild traumatic brain injury (mTBI) is a leading cause of sustained cognitive impairment in military service members and Veterans. However, the mechanism of persistent cognitive deficits including working memory (WM) dysfunction is not fully understood in mTBI. Few studies of WM deficits in mTBI have taken advantage of the temporal and frequency resolution afforded by electromagnetic measurements. Using magnetoencephalography (MEG) and an N-back WM task, we investigated functional abnormalities in combat-related mTBI. Study participants included 25 symptomatic active-duty service members or Veterans with combat-related mTBI and 20 healthy controls with similar combat experiences. MEG source-magnitude images were obtained for alpha (8-12 Hz), beta (15-30 Hz), gamma (30-90 Hz), and low-frequency (1-7 Hz) bands. Compared with healthy combat controls, mTBI participants showed increased MEG signals across frequency bands in frontal pole (FP), ventromedial prefrontal cortex, orbitofrontal cortex (OFC), and anterior dorsolateral prefrontal cortex (dlPFC), but decreased MEG signals in anterior cingulate cortex. Hyperactivations in FP, OFC, and anterior dlPFC were associated with slower reaction times. MEG activations in lateral FP also negatively correlated with performance on tests of letter sequencing, verbal fluency, and digit symbol coding. The profound hyperactivations from FP suggest that FP is particularly vulnerable to combat-related mTBI.

Keywords: blast brain injury; frontal pole; magnetoencephalography; traumatic brain injury; working memory.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Adult
Brain / physiopathology*
Brain Concussion / etiology
Brain Concussion / physiopathology*
Brain Concussion / psychology*
Brain Waves
Combat Disorders / complications
Combat Disorders / pathology*
Combat Disorders / physiopathology*
Humans
Magnetoencephalography
Male
Memory, Short-Term / physiology*
Neuropsychological Tests
Veterans

Abstract

Publication types

MeSH terms

Grants and funding