BACKGROUND AND PURPOSE: In 1948, Paul Yakovlev described an additional limbic circuit located basolateral to James Papez's circuit (1937) and included orbitofrontal cortex, amygdala, and dorsomedial nucleus of thalamus. This circuit is shown to be an important component of subcortical cognitive abilities. We aimed to demonstrate this circuit in a multiple sclerosis (MS) cohort using diffusion tensor imaging (DTI) and evaluate its role in MS-related cognitive impairment (CI). METHODS: We enrolled cognitively intact (n = 10) and impaired (n = 36) MS patients who underwent a comprehensive cognitive assessment; the minimal assessment of cognitive function in MS (MACFIMS) and structural magnetic resonance imaging. Correlation analyses between volumetric and DTI-derived values of the orbitofrontothalamic (OFT), amygdalothalamic tracts (ATTs), and dorsomedial nucleus of thalamus and CI index derived from MACFIMS were computed after adjustment for age, education, and lesion load. RESULTS: We observed a consistent trend between CI index and bilateral dorsomedial nucleus’ mean diffusivity (MD) (r =.316; P =.02), left OFT Fractional anisotropy (FA) (r = −.302; P =.02), MD (r =.380;.006), and radial diffusivities (RDs) (r =.432; P =.002), also with right ATT FA (r = −.475; P =.0006) and left ATT FA (= −.487; P =.0005). After Bonferroni correction, correlations of left OFT RD and right and left ATT FA with CI were found to be significant. CONCLUSIONS: Our study provides in vivo DTI delineation of Yakovlev's historical basolateral limbic circuit and establishes a role in MS-related CI. These findings may potentially pave the way for future clinical studies using targeted invasive and noninvasive neurostimulation modalities for CI in MS.
Bibliographical noteFunding Information:
and Disclosure: This study was funded by a K-23 (the project # K23 NS072134) training award to FN and DUNN research foundation to KH. We wish to thank Vipul Kumar Patel for helping in data acquisition. The authors have no potential conflict of interest to disclose.
Correspondence: Address correspondence to Zafer Keser, MD, Department of Neurology, University of Texas McGovern Medical School, 6431 Fannin St. Suite 7.044, Houston, TX 77030. E-mail: Zafer.Keser@uth.tmc.edu Acknowledgments and Disclosure: This study was funded by a K-23 (the project # K23 NS072134) training award to FN and DUNN research foundation to KH. We wish to thank Vipul Kumar Patel for helping in data acquisition. The authors have no potential conflict of interest to disclose.
© 2018 by the American Society of Neuroimaging
- Cognitive impairment
- diffusion tensor imaging
- multiple sclerosis