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Introduction: Accumulating evidence indicates that the amygdala exhibits early signs of Alzheimer's disease (AD) pathology. However, it is still unknown whether the atrophy of distinct subfields of the amygdala also participates in the transition from healthy cognition to mild cognitive impairment (MCI).
Methods: Our sample was derived from the AD Neuroimaging Initiative 3 and consisted of 97 cognitively healthy (HC) individuals, sorted into two groups based on their clinical follow-up: 75 who remained stable (s-HC) and 22 who converted to MCI within 48 months (c-HC). Anatomical magnetic resonance (MR) images were analyzed using a semi-automatic approach that combines probabilistic methods and a priori information from ex vivo MR images and histology to segment and obtain quantitative structural metrics for different amygdala subfields in each participant. Spearman's correlations were performed between MR measures and baseline and longitudinal neuropsychological measures. We also included anatomical measurements of the whole amygdala, the hippocampus, a key target of AD-related pathology, and the whole cortical thickness as a test of spatial specificity.
Results: Compared with s-HC individuals, c-HC subjects showed a reduced right amygdala volume, whereas no significant difference was observed for hippocampal volumes or changes in cortical thickness. In the amygdala subfields, we observed selected atrophy patterns in the basolateral nuclear complex, anterior amygdala area, and transitional area. Macro-structural alterations in these subfields correlated with variations of global indices of cognitive performance (measured at baseline and the 48-month follow-up), suggesting that amygdala changes shape the cognitive progression to MCI.
Discussion: Our results provide anatomical evidence for the early involvement of the amygdala in the preclinical stages of AD.
Highlights: Amygdala's atrophy marks elderly progression to mild cognitive impairment (MCI).Amygdala's was observed within the basolateral and amygdaloid complexes.Macro-structural alterations were associated with cognitive decline.No atrophy was found in the hippocampus and cortex.
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http://dx.doi.org/10.1002/trc2.12436 | DOI Listing |
J Psychiatr Res
August 2025
Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan. Electronic address:
Background: Ketamine is effective for treatment-resistant depression (TRD), where its mechanism remains unclear. Though the amygdala plays an important role in emotional processing and mood state, no study has explored the relationship between amygdalar subfield volumes and ketamine's effect in patients with TRD. We hypothesized that amygdalar subfield volume changes would correlate with clinical response to ketamine in patients with TRD.
View Article and Find Full Text PDFEpileptic Disord
August 2025
Department of Epilepsy, Movement Disorders and Physiology, Kyoto University, Kyoto, Japan.
Background: Late-onset temporal lobe epilepsy (TLE) sometimes manifests with enlargement of the amygdala or hippocampus. This study aimed to clarify the yet unknown clinical significance of amygdala-hippocampal enlargement in late-onset TLE.
Methods: We retrospectively analyzed the late-onset TLE (≥ 60 years old) patients admitted to Kyoto University Hospital between 2000 and 2019.
Psychol Med
August 2025
Department of Psychological Medicine, https://ror.org/0220mzb33Institute of Psychiatry, Psychology, and Neuroscience, King's College London, London, UK.
Background: Preclinical evidence suggests that diazepam enhances hippocampal γ-aminobutyric acid (GABA) signalling and normalises a psychosis-relevant cortico-limbic-striatal circuit. Hippocampal network dysconnectivity, particularly from the CA1 subfield, is evident in people at clinical high-risk for psychosis (CHR-P), representing a potential treatment target. This study aimed to forward-translate this preclinical evidence.
View Article and Find Full Text PDFBrain Res Bull
August 2025
Department of Radiology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China. Electronic address:
Background: We aimed to investigate the pattern of atrophy in the hippocampus and amygdala subregions in patients with retinal detachment (RD) and its correlation with cognition and emotion.
Methods: The study recruited 32 patients diagnosed with RD alongside 33 healthy controls (HCs), carefully matched for sex and age. Magnetic resonance imaging (MRI) scans of all participants underwent automated segmentation to delineate hippocampal and amygdala subfields, utilizing FreeSurfer v6.
World J Diabetes
July 2025
Department of Radiology, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
Background: Increasing evidence has shown that hippocampal damage serves as a marker of early cognitive decline in patients with type 2 diabetes mellitus (T2DM); however, the association between hippocampal subregion volume changes and cognitive decline in different dimensions remains unclear.
Aim: To investigate changes in hippocampal subregion volumes in patients with T2DM and their relationship with cognitive function impairment.
Methods: Sixty patients with T2DM and 32 healthy controls were recruited.