Page 80 - MEGIN Book Of Abstracts - 2023

Prominent gamma band activity during visual activity in AD patients. Moreover, positive correlation
motion perception in early-stage Alzheimer's between induced gamma activity and cognitive perfor-
disease (2022) mance might signify a compensating mechanism of in-
hibitory neurons which preserve the pyramidal neuron
Naito, Nobushige; Hirosawa, Tetsu; Tsubomoto, Makoto; from excitotoxicity in a posterior association area.
Miyagishi, Yoshiaki; Kikuchi, Mitsuru
PloS one (2022), Vol. 17, No. 4 (35436287) (0 citations)
Department of Psychiatry & Behavioral Science, Kanazawa
University, Kanazawa, Japan; Research Center for Child Men-
tal Development, Kanazawa University, Kanazawa, Japan Oscillatory Activity of the Hippocampus in
Prodromal Alzheimer's Disease: A Source-Space
INTRODUCTION Alzheimer's disease (AD) affects Magnetoencephalography Study (2022)
multiple neural pathways and regions, resulting in
various visual impairments such as motion perception. Luppi, Janne J; Schoonhoven, Deborah N; van Nifterick,
Generally, gamma-band activities during visual motion Anne M; Gouw, Alida A; Hillebrand, Arjan; Scheltens,
perception have been thought to reflect ongoing cog- Philip; Stam, Cornelis J; de Haan, Willem
nitive processes. Nevertheless, few studies have specifi-
cally examined induced gamma band activity during vi- Alzheimer Center and Department of Neurology, Amsterdam
sual motion perception in AD patients. Therefore, after Neuroscience, VU University Medical Center, Amsterdam
performing magnetoencephalography (MEG) recording UMC, The Netherlands; Department of Clinical Neurophysiol-
during apparent motion (AM) stimulation for the left ogy and MEG, Amsterdam Neuroscience, VU University Medi-
hemi-visual field in patients diagnosed as having AD in cal Center, Amsterdam UMC, The Netherlands
the early stage, we compared the results with findings
of cognitive performance. BACKGROUND In Alzheimer's disease (AD), oscillatory
activity of the human brain slows down. However, oscil-
METHODS Seventeen AD patients in the early stage latory slowing varies between individuals, particularly
and 17 controls matched for age, sex, and educa- in prodromal AD. Cortical oscillatory changes have
tional attainment participated in this study. For each shown suboptimal accuracy as diagnostic markers. We
participant, memory performance was assessed with speculated that focusing on the hippocampus might
the Mini-Mental State Examination (MMSE) and the prove more successful, particularly using magnetoen-
Wechsler Memory Scale-Revised (WMS-R). For MEG cephalography (MEG) for capturing subcortical oscilla-
analysis, we examined power changes induced in a tory activity.
higher frequency range (20-100 Hz) after AM stimuli.
OBJECTIVE We explored MEG-based detection of hip-
RESULTS The power of induced gamma band activities pocampal oscillatory abnormalities in prodromal AD
was significantly higher in AD patients. The power of patients.
induced gamma band activities was associated with
higher performance on both MMSE and WMS-R tests METHODS We acquired resting-state MEG data of 18
for attention and concentration in AD patients. AD dementia patients, 18 amyloid-β-positive amnes-
tic mild cognitive impairment (MCI, prodromal AD)
CONCLUSIONS Given that neuronal dysfunction in AD patients, and 18 amyloid-β-negative persons with
is associated with excitotoxic neurodegeneration, and subjective cognitive decline (SCD). Oscillatory activ-
given that subsequent development of compensatory ity in 78 cortical regions and both hippocampi was
inhibitory mechanisms also contributes to pathol- reconstructed using beamforming. Between-group
ogy in AD patients, elevated gamma band oscillations and hippocampal-cortical differences in spectral power
might reflect an imbalance of inhibitory and excitatory

 ontents  Index 59
C