Page 94 - MEGIN Book Of Abstracts - 2023

Translational Research in Biomedicine, Kaohsiung Chang Keywords: APOE4, MEG, MRI, mismatch negativity, subjec-
Gung Memorial Hospital, Chang Gung University College tive memory complaint
of Medicine, Kaohsiung, Taiwan; Department of Neurology,
Chang Gung Memorial Hospital, Linkou, Taiwan; Laboratory Psychophysiology (2021), Vol. 58, No. 6 (33792049) (3
of Brain Imaging and Neural Dynamics (BIND Lab), Chang citations)
Gung University, Taoyuan, Taiwan; Department of Neurology,
National Yang-Ming Chiao-Tung University, Taipei, Taiwan;
Brain Research Center, National Yang-Ming Chiao-Tung Neuromagnetic evidence of abnormal automatic
University, Taipei, Taiwan inhibitory function in subjective memory complaint
(2021)
ABSTRACT The cross-sectional identification of sub-
jective cognitive decline (SCD) in cognitively normal Sun, Hua-Hsuan; Lin, Mei-Yin; Nouchi, Rui; Wang, Pei-
adults is particularly important for the early effective Ning; Cheng, Chia-Hsiung
prevention or intervention of the future development
of mild cognitive impairments (MCI) or Alzheimer's Bali Psychiatric Center, Ministry of Health and Welfare, New
disease (AD). A pre-attentive neurophysiological signal Taipei City, Taiwan; Department of Physical Medicine and
that reflects the brain's ability to detect the changes Rehabilitation, Taichung Hospital, Ministry of Health and
of the environment is called mismatch negativity Welfare, Taichung, Taiwan; Smart Aging Research Center
(MMN) or its magnetic counterpart (MMNm). It has (S.A.R.C), Tohoku University, Sendai, Japan; Department of
been shown that patients with MCI or AD demonstrate Neurology, National Yang Ming Chiao Tung University, Taipei,
reduced MMN/MMNm responses, while the exact pro- Taiwan; Department of Psychiatry, Chang Gung Memorial
file of MMN/MMNm in SCD is substantially unknown. Hospital, Linkou, Taiwan
We applied magnetoencephalographic recordings to
interrogate MMNm activities in healthy controls (HC, ABSTRACT Subjective memory complaint (SMC), a self-
n = 29) and individuals with SCD (n = 26). Furthermore, perceived worsening in memory capacity concurrent
we analyzed gray matter (GM) volumes in the MMNm- with normal performance on standardized cognitive
related regions through voxel-based morphometry and assessments, is considered a risk factor for the devel-
performed apolipoprotein E4 (APOE4) genotyping for opment of Alzheimer's disease (AD). Deficient sensory
all the participants. Our results showed that there were gating (SG), referring to the lack of automatic inhibition
no significant differences in GM volume and propor- of neural responses to the second identical stimulus,
tions of APOE4 carriers between HC and SCD groups. has been documented in prodromal and incident AD
However, individuals with SCD exhibited weakened patients. However, it remains unknown whether the
z-corrected MMNm responses in the left inferior cognitively normal elderly with SMC demonstrate al-
parietal lobule and right inferior frontal gyrus (IFG) as terations of SG function compared with those without
compared to HC. Based on the regions showing signifi- SMC. A total of 19 healthy controls (HC) and 16 SMC
cant between-group differences, z-corrected MMNm subjects were included in the present study. Neural
amplitudes of the right IFG significantly correlated with responses to the auditory paired-stimulus paradigm
the memory performance among the SCD participants. were recorded by the magnetoencephalography and
Our data suggest that neurophysiological changes of analyzed by the distributed source imaging method
the brain, as indexed by MMNm, precede structural of minimum norm estimate. The SG of M50 and M100
atrophy in the individuals with SCD compared to those components were measured using the amplitude
without SCD. ratio of the second response over the first response at
the cortical level. Compared to HC, subjects with SMC
showed significantly increased M50 SG ratios in the
inferior parietal lobule (IPL). Furthermore, M50 SG ratios
in the right IPL yielded an acceptable discriminative

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