Yu mei Zhang MD, Presenter: Nothing to Disclose

Cheng wei Wang MD, Abstract Co-Author: Nothing to Disclose

Hong Yang MD, Abstract Co-Author: Nothing to Disclose

Zhan Feng, Abstract Co-Author: Nothing to Disclose

Yong Li, Abstract Co-Author: Nothing to Disclose

To evaluate the effective resting-state functional connectivity between PCC and other brain region and to understand the neuropathological mechanisms of amnestic mild cognitive impairment (aMCI), using Granger causality analysis method.

The effective connectivity between PCC and other brain regions was compared between 13 aMCI patients (aged 65.5 ± 9.7) and 14 healthy group-matched on age, sex and education controls (aged 65.9 ± 9.1)；The recruited patients demonstrated CDR scores of 0.5 and matched Petersen’s criteria with the neuropsychological examination. Imaging data were collected on a 3 T MR (GE Signa HDx). Functional data were acquired using a single shot GRE EPI sequence (TR/TE =2000/35 ms, flip angle=90°,FOV=256mm2, matrix= 64×64, 36 slices, slice thickness=3 mm, and 1 mm interslice）.Structural data was acquired via a 3D fast field echo T1-weighted sequence (sagittal, TR/TE =8.2/3.2ms , flip angle=12°, FOV=256mm2, matrix= 256 × 256, slice thickness 1 mm, no gap, in-plane voxel size 1 mm × 1 mm). Resting-state fMRI data analysis was performed using the DPARSF and REST-GCA software. The results of posterior cingulated cortex (PCC) in the Meta analysis of aMCI were applied as the coordinates of the seed point for GCA analysis based on coefficient. Effective connectivity from PCC to brain region and vice versa were achieved. Two-sample T test was applied for the analysis of the differences of effective connectivity between the two groups.  

Significant lower connectivity (P<0.01) was observed in aMCI patients compared to controls, with decreased effective connectivity from PCC to the left cerebellar hemisphere, the left medial temporal lobe and bilateral prefrontal. Nevertheless, while considering the whole brain region connected to the PCC, connectivity enhanced in right thalamus, the left cerebellar hemisphere, the left superior temporal gyrus; where decreased in left frontal lobe, the left orbital gyrus.

The cognitive control functions reduced in aMCI, especially in the left frontal lob; The compensatory mechanisms of brain were active when the nerve transduction pathway was damaged. The loop of left cerebellar hemisphere and PCC may participate in the integration and management of episodic memory.

Cognitive function disorders are observed in aMCI patients, which may provide information on the neuropathological mechanisms of aMCI.

Zhang, Y, Wang, C, Yang, H, Feng, Z, Li, Y, Effective Connectivity of Amnestic Mild Cognitive Impairment Based on Granger Causality Analysis.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010265.html