Dataset Description: This dataset encompasses information extracted from a systematic review on associative learning (generalization) in the context of aging and AD. Data was systematically collected from studies published between 2004 and 2024, covering neuroimaging measures linked to cognitive function and aging. Key elements of the dataset include publication details (authors, year, journal), sample sizes, neuroimaging modalities used, DOI links, and reported outcomes. The dataset integrates neuroimaging findings from structural MRI, resting-state functional MRI (rs-fMRI), task-based fMRI, and Diffusion Tensor Imaging (DTI) with cognitive performance across generalization tasks. Studies predominantly utilized MRI scanners at field strengths of 1.5 Tesla, 3 Tesla, 4 Tesla, and 7 Tesla, with a focus on regions such as the medial temporal lobe, hippocampus, frontal and temporal lobes, parietal lobe, precuneus, subcortical and thalamic regions, cingulate and caudate, as well as the cerebellum. Methodology The protocol for the metadata analysis was pre-registered on AsPredicted (#187862) and followed a rigorous systematic review process. Searches were conducted on PubMed and EMBASE to identify peer-reviewed studies published in English between 2004 and 2024 that investigated associative learning in relation to aging and AD. Inclusion criteria required that studies involved participants aged 45 years or older and included clinical diagnoses of cognitive impairment such as mild cognitive impairment (MCI), AD, or dementia, along with neuroimaging techniques. Exclusion criteria were applied to filter out animal studies, review papers, case studies, studies unrelated to aging and AD, those without MRI data, and those involving only participants younger than 45 years. The search strategy utilized a broad set of keywords related to generalization, cognitive decline, neuroimaging, AD, and memory processes, ensuring the identification of all relevant studies. Each stage of the systematic review—database search, duplicate removal, title and abstract screening, and full-text evaluation—was documented and summarized in a PRISMA flow diagram. Extracted data included authors, year of publication, sample size, neuroimaging modalities, reported outcomes, and journal titles. The dataset was meticulously organized and unrelated studies were excluded based on the predefined criteria, leading to a comprehensive compilation of studies examining the impact of aging and neurodegeneration on generalization and associated neuroimaging markers.

Variable Type Width Decimals Label Values Missing Columns Align Measure Author String 10 0 First Author of the Study None 10 Left Nominal Year Numeric 5 0 Year of the Study -9 11 Right Scale Aging Status Numeric 2 0 Cognitive State (HC: Healthy Controls; MCI: Mild Cognitive Impairment; AD: Alzheimer's Disease) HC-1, MCI-2, AD-3, MCIvsHC-4, ADvsHC-5, MCIvsAD-6 -9 11 Right Nominal Overall N Numeric 3 0 Overall Number of Participants -9 11 Right Scale Overall Mean Age Numeric 5 2 Overall - Mean Age (years) -9 11 Right Scale Overall Age SD Numeric 4 2 Overall Age SD -9 11 Right Scale HC N Numeric 3 0 HC- Number of Participants -9 11 Right Scale HC Mean Age Numeric 5 2 HC-Mean Age (years) -9 11 Right Scale HC Age SD Numeric 4 2 HC-Age SD -9 11 Right Scale MCI N Numeric 3 0 MCI Number of Participants -9 11 Right Scale MCI Mean Age Numeric 5 2 MCI-Mean Age (years) -9 11 Right Scale MCI Age SD Numeric 3 2 MCI-Age SD -9 11 Right Scale AD N Numeric 3 0 AD-Number of Participants -9 11 Right Scale AD Mean Age Numeric 5 2 AD-Mean Age (years) -9 11 Right Scale AD Age SD Numeric 4 2 AD-Age SD -9 11 Right Scale Effect Size Numeric 8 4 Effect Size (Cohen's d) -9 11 Right Scale Standard Error Numeric 8 4 Standard Error -9 11 Right Scale Cognitive Task Numeric 8 0 Generalization Task Modality Generalization-1 Face-Name-2 Paired Association-3 Pattern/Spatial-4 Associative Memory/Discrimination-5 -9 8 Right Nominal ROI Numeric 8 0 Region of Interest Medial Temporal Lobe and Hippocampal Subfields-1 Frontal and Temporal Lobe-2 Parietal and Precuneus Regions-3 Subcortical and Thalamic Regions-4 Cingulate and Caudate-5 Cerebellum-6 -9 8 Right Nominal MRI Modality Numeric 8 0 Neuroimaging Modality No Specified-0, Structural MRI-1, Task-Based MRI-2, DRI-3, rsMRI-4, Multiple-5 -9 8 Right Nominal MRI Scanner Numeric 8 0 MRI Scanner Tesla No Specified-0, 1.5T-1, 3.0T-2, 4.0T-3, 7.0T-4 -9 8 Right Nominal Atlas String 8 0 Atlas Type None 8 Left Nominal Coordinates String 8 0 ROI Coordinates None 8 Left Nominal Key: HC: Healthy Controls; MCI: Mild Cognitive Impairment; AD: Alzheimer's Disease; SD: standard Deviation;

Abstract: This dataset supports a comprehensive metadata analysis aimed at exploring emerging evidence for generalization deficits as a sensitive early measure of cognitive and neural decline in Alzheimer's disease (AD). It includes data on neuroimaging biomarkers, cognitive performance metrics related to generalization, and study-specific metadata extracted from multiple peer-reviewed publications. The data was curated and standardized to facilitate comparisons across studies, focusing on multimodal approaches to understanding aging and AD. This dataset serves as a resource for researchers investigating the interrelationships between generalization and neuroimaging, contributing to early AD diagnosis and interventions. It can be used for further meta-analyses, training predictive models, and hypothesis generation in aging and neuroimaging research.