Hong LI, Abstract Co-Author: Nothing to Disclose

Haibo Xu, Presenter: Nothing to Disclose

Haiwei Han, Abstract Co-Author: Nothing to Disclose

Jingtao Zhang, Abstract Co-Author: Nothing to Disclose

Ming Yuchi, Abstract Co-Author: Nothing to Disclose

Cheng Luo, Abstract Co-Author: Nothing to Disclose

This study investigated the alterations of the functional connectivity between the hippocampus and the other brain regions associated with visual memory in mesial temporal epilepsy (mTLE) patients during resting state of brain by resting-state fMRI.

22 mTLE patients diagnosed by the comprehensive use of detailed history and neurological examinations, scalp EEG with sphenoidal electrodes, conventional magnetic resonance imaging (cMRI) were performed resting-state fMRI. They were divided into two groups according to the side of epileptogenic focus, that is, right mTLE group and left mTLE group. 12 healthy volunteers with known absence of neurological or psychiatric disorders were recruited as controls. The "seed voxel" approach was used to examine the hippocampal connectivity on the resting-state fMRI data so as to define the right hippocampus as “seed voxel” in right mTLE group, and likewise, the left hippocampus as “seed voxel” in left mTLE group. In addition, regional spontaneous low-frequency (<0.08 Hz) blood oxygenation level dependent fluctuations (LFBF) coherence patterns in mTLE group was examined and compared with the control group.

The right mTLE group showed more decrease in functional connectivity of visual-related regions.The left mTLE group showed more severely and extensively disrupted functional connectivity than the right mTLE group. In the right mTLE group, the patients showed significantly decreased ReHo in the cuneus and precuneus. Moreover, significantly increased ReHo correlations were found in the right cerebellum and right superior temporal gyrus.In the left mTLE group, documented was significantly increased ReHo at bilateral fusiform, precentral gyrus, postcentral, middle cingulate gyrus, left middle frontal gyrus, and significantly decreased ReHo at medial frontal gyrus, posterior cingulate, and thalamus.

This study demonstrated that impaired hippocampal functional connectivity in the mTLE patients induced widely regional variation at the default-mode network. It is noted that the alteration of functional connectivity in the right mTLE group might be closely associated with visuo-spatial memory. While global functional connectivity impairment and lower correlation of intra-hippocampus tended to be present in the left mTLE patients.

Resting-state fMRI may be of potential clinical assessment of abnormal visuo-spatial memory associated with mTLE.

LI, H, Xu, H, Han, H, Zhang, J, Yuchi, M, Luo, C, The Altered Function Connectivity Associated with Visual Memory in the Right Mesial Temporal Epilepsy: Evidence from the Resting State fMRI.  Radiological Society of North America 2012 Scientific Assembly and Annual Meeting, November 25 - November 30, 2012 ,Chicago IL. http://archive.rsna.org/2012/12020350.html