Frontolimbic brain networks predict depressive symptoms in temporal lobe epilepsy

Nobuko Kemmotsu; N Erkut Kucukboyaci; Kelly M Leyden; Christopher E Cheng; Holly M Girard; Vicente J Iragui; Evelyn S Tecoma; Carrie R McDonald

doi:10.1016/j.eplepsyres.2014.08.018

Frontolimbic brain networks predict depressive symptoms in temporal lobe epilepsy

Epilepsy Res. 2014 Nov;108(9):1554-63. doi: 10.1016/j.eplepsyres.2014.08.018. Epub 2014 Aug 30.

Authors

Nobuko Kemmotsu¹, N Erkut Kucukboyaci², Kelly M Leyden³, Christopher E Cheng⁴, Holly M Girard⁵, Vicente J Iragui⁶, Evelyn S Tecoma⁷, Carrie R McDonald⁸

Affiliations

¹ Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA. Electronic address: nkemmotsu@ucsd.edu.
² Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA; SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA. Electronic address: erkut@ucsd.edu.
³ Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA. Electronic address: kleyden@ucsd.edu.
⁴ Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA. Electronic address: cecheng90@gmail.com.
⁵ SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA. Electronic address: hmgirard@gmail.com.
⁶ Department of Neuroscience, University of California, San Diego, La Jolla, CA, USA. Electronic address: viragui@ucsd.edu.
⁷ SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA; Department of Neuroscience, University of California, San Diego, La Jolla, CA, USA. Electronic address: etecoma@ucsd.edu.
⁸ Multimodal Imaging Laboratory, University of California, San Diego, La Jolla, CA, USA; Department of Psychiatry, University of California, San Diego, La Jolla, CA, USA; SDSU/UCSD Joint Doctoral Program in Clinical Psychology, San Diego, San Diego, CA, USA. Electronic address: camcdonald@ucsd.edu.

Abstract

Psychiatric co-morbidities in epilepsy are of great concern. The current study investigated the relative contribution of structural and functional connectivity (FC) between medial temporal (MT) and prefrontal regions in predicting levels of depressive symptoms in patients with temporal lobe epilepsy (TLE). Twenty-one patients with TLE [11 left TLE (LTLE); 10 right TLE (RTLE)] and 20 controls participated. Diffusion tensor imaging was performed to obtain fractional anisotropy (FA) of the uncinate fasciculus (UF), and mean diffusivity (MD) of the amygdala (AM) and hippocampus (HC). Functional MRI was performed to obtain FC strengths between the AM and HC and prefrontal regions of interest including anterior prefrontal (APF), orbitofrontal, and inferior frontal regions. Participants self-reported depression symptoms on the Beck Depression Inventory-II. Greater depressive symptoms were associated with stronger FC of ipsilateral HC-APF, lower FA of the bilateral UF, and higher MD of the ipsilateral HC in LTLE, and with lower FA of the contralateral UF in RTLE. Regression analyses indicated that FC of the ipsilateral HC-APF was the strongest contributor to depression in LTLE, explaining 68.7% of the variance in depression scores. Both functional and microstructural measures of frontolimbic dysfunction were associated with depressive symptoms. These connectivity variables may be moderating which patients present with depression symptoms. In particular, FC MRI may provide a more sensitive measure of depression-related dysfunction, at least in patients with LTLE. Employing sensitive measures of frontolimbic network dysfunction in TLE may help provide new insight into mood disorders in epilepsy that could eventually guide treatment planning.

Keywords: Comorbidity; DTI; Depression; Functional connectivity; Temporal lobe epilepsy; Uncinate facsiculus.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Anisotropy
Brain Mapping
Cognition Disorders / etiology
Depression / diagnosis*
Depression / etiology*
Diffusion Magnetic Resonance Imaging
Electroencephalography
Epilepsy, Temporal Lobe / complications*
Epilepsy, Temporal Lobe / psychology
Female
Frontal Lobe / pathology*
Functional Laterality
Humans
Image Processing, Computer-Assisted
Limbic System / pathology*
Magnetic Resonance Imaging
Male
Middle Aged
Nerve Net / pathology
Neuropsychological Tests
Predictive Value of Tests
Psychiatric Status Rating Scales
Video Recording
Young Adult

Abstract

Publication types

MeSH terms

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