Dysfunction of Inferior Parietal Lobule During Sensory Gating in Patients With Amnestic Mild Cognitive Impairment

Chia-Hsiung Cheng; Fu-Jung Hsiao; Yu-Wei Hsieh; Pei-Ning Wang

doi:10.3389/fnagi.2020.00039

Dysfunction of Inferior Parietal Lobule During Sensory Gating in Patients With Amnestic Mild Cognitive Impairment

Front Aging Neurosci. 2020 Feb 25:12:39. doi: 10.3389/fnagi.2020.00039. eCollection 2020.

Authors

Chia-Hsiung Cheng^{1

2

3

4}, Fu-Jung Hsiao⁵, Yu-Wei Hsieh^{1

2

6}, Pei-Ning Wang^{5

7

8}

Affiliations

¹ Department of Occupational Therapy, Graduate Institute of Behavioral Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
² Healthy Aging Research Center, Chang Gung University, Taoyuan, Taiwan.
³ Department of Psychiatry, Chang Gung Memorial Hospital, Linkou, Taiwan.
⁴ Laboratory of Brain Imaging and Neural Dynamics (BIND Lab), Chang Gung University, Taoyuan, Taiwan.
⁵ Brain Research Center, National Yang-Ming University, Taipei, Taiwan.
⁶ Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Linkou, Taiwan.
⁷ Division of General Neurology, Department of Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.
⁸ Department of Neurology, National Yang-Ming University, Taipei, Taiwan.

Abstract

Patients with amnestic mild cognitive impairment (aMCI) demonstrate significant cognitive deficits, especially in the memory aspect. The memory deficiency might be attributed to the difficulties in the inhibitory function to suppress redundant stimuli. Sensory gating (SG) refers to the attenuation of neural responses to the second identical stimulus in a paired-click paradigm, in which auditory stimuli are delivered in pairs with inter-stimulus intervals (ISI) of 500 ms and inter-pair intervals of 6-8 s. It is considered as an electrophysiological signal to reflect the brain's automatic response to gate out repetitive sensory inputs. However, there has been no study systematically investigating SG function in aMCI patients. Thus, the present study used magnetoencephalography (MEG) to record neuromagnetic responses to a paired-click paradigm in 23 healthy controls (HC) and 26 aMCI patients. The Stimulus 2/Stimulus 1 (S2/S1) amplitude ratio was used to represent the SG function. Compared to HC, aMCI patients showed M50 SG deficits in the left inferior frontal gyrus (IFG) and right inferior parietal lobule (IPL). M100 SG defects were also observed in the right IPL. Based on the ROIs showing significant between-group SG differences, we found that a more deficient M50 SG function in the right IPL was associated with poorer performance in the immediate recall of Logic Memory (LM), Chinese Version Verbal Learning Test (CVVLT) and Digit Span Backward (DSB) Test. Furthermore, the M50 SG ratios of the right IPL together with the neuropsychological performance of LM and CVVLT demonstrated very good accuracy in the discrimination of aMCI from HC. In conclusion, compared to HC, aMCI patients showed a significant SG deficit in the right IPL, which was correlated with the auditory short-term memory function. We suggest the combination of SG in the right IPL, LM and CVVLT to be sensitive indicators to differentiate aMCI patients from HC.

Keywords: aging; inhibitory control; magnetoencephalography (MEG); mild cognitive impairment; sensory gating.