The goal of this study is to conduct a Stage I pilot study examining the feasibility, acceptability, and preliminary effects of an internet-based, asynchronous mindfulness-based stress reduction program (iMBSR) compared to an internet-based, asynchronous lifestyle education program (iLifeEd), for adults at-risk for Alzheimer's disease (AD). Sixty middle-aged and older adults (aged 50 years or older) with subjective cognitive decline will be randomized to either an 8-week iMBSR program or an 8-week iLifeEd program control group, designed to provide adequate control for placebo effects. Behavioral, neuroimaging, and ecological momentary assessment (EMA) measures of mind-wandering will be administered to determine preliminary effects as a function of engagement in the iMBSR program. AD biomarkers will be examined at pre-training and post-training assessments.

A significant limiting factor in the prognosis of AD is the absence of targeted pharmaceutical or behavioral interventions to arrest or reduce the neurodegeneration resulting from the accumulation of two key proteinopathies once cognitive symptoms are observable. In fact, in AD stage sequencing, the aggregation of Aβ in neural plaques followed by tau accumulation in neurofibrillary tangles, predates the onset of known cognitive symptoms-at times one to two decades before observable changes in cognition. Additionally, midline cortical structures of the DMN are the first sites of AD pathophysiology with activity of the DMN heavily linked with internally directed cognitions. Although these internally directed cognitions are adaptive, the ongoing nature of these spontaneous cognitions has a downstream negative impact for overall cognition, psychological well-being, and potentially, is also linked with AD pathophysiology. Mindfulness training, with its cultivation of present moment awareness, has shown promising support for its potential to reduce mind-wandering and strengthen the neural circuitry supporting sustained attention. More recently, there has also been support for mindfulness to be positively associated with lower levels of Aβ and tau pathology. Thus, the primary goal of this study is to evaluate the feasibility, acceptability, and preliminary effects of an internet-based mindfulness training program on mind-wandering, neural connectivity of the DMN, and plasma-based biomarkers of Aβ and tau pathology, which has the potential to make a significant contribution to the prevention of AD-related cognitive decline. The main hypothesis is that the iMBSR program will be feasible and acceptable and improve neural, behavioral, and EMA measures of mind-wandering and slow the accumulation of AD biomarkers. Feasibility will be defined through evaluation of recruitment, retention, and drop-out rates. Acceptability will be defined by assessing prospective acceptability, participant attendance, and program satisfaction. The investigators hypothesize that iMBSR and iLifeEd will be feasible and acceptable for adults with subjective cognitive decline, and that participants in the iMBSR group will also report lower levels of subjective cognitive decline. The investigators additionally hypothesize that iMBSR training will result in a reduction of mind-wandering thoughts and reaction time coefficient of variation (RT_CV) immediately following training. The investigators also hypothesize that network strength in the default mode network (DMN) will increase following training in the iMBSR protocol compared with the iLifeEd training. For plasma markers of amyloid and tau pathology, the investigators hypothesize that there will be a lower rate of accumulation in amyloid and tau pathology in the iMBSR group compared with the iLifeEd group.

Inclusion Criteria:

• Aged 50 years or greater
• Capable of attending screening and assessment sessions and the internet-based intervention modules
• Fluent English speaker
• Corrected (near and far) visual acuity of 20/40 or better
• Adequate hearing for experimental purposes
• Absence of diagnosed terminal illness
• Absence of diagnosed neurological disorders
• No history of psychotic disorder or substance abuse disorder diagnosed by a psychologist or psychiatrist
• Absence of medication use that significantly alters brain activity
• No history of diagnosed learning disability that would interfere with the completion of the cognitive tasks
• Report elevated scores on the self-report Everyday Cognition (E-Cog)-39 subjective cognitive decline with normatively intact performance on cognitive testing (as determined by the neuropsychological battery)
• No evidence of mild cognitive impairment or dementia as assessed by the neuropsychological measures from the National Alzheimer's Coordinating Center (NACC) Uniform Data Set OR inadequate self-reported performance of instrumental activities of daily living
• Ability to engage in light stretching/movement-based activities with or without assistive devices
• Absence of any MRI contraindications
• Not pregnant and not attempting to become pregnant
• Absence of self-reported claustrophobia
• No regular practice of meditation or yoga (defined as once or more per week) AND No previous participation in a structured mindfulness class (e.g., Mindfulness-Based Stress Reduction, intensive meditation retreat)
• Access to internet and at-home computer with a working microphone and video
• Not enrolled in other RCTs examining the efficacy of exercise training, cognitive rehabilitation, stress management, progressive muscle relaxation or other health-based rehabilitation

Exclusion Criteria:

• Aged less than 50 years
• Any physical or pragmatic limitation that prohibits attendance of screening or assessment sessions, or intervention engagement
• No fluency in English
• Corrected (near or far) visual acuity worse than 20/40
• Self-reported hearing impairment that would affect ability to hear the experimenter
• Diagnosis of terminal illness
• Presence of diagnosed neurological disorders such as: Alzheimer's disease, Vascular Dementia, Parkinson's disease, Multiple Sclerosis, Traumatic Brain Injury, Fronto-Temporal Lobar Degeneration, Lewy Body Disease
• History of psychotic disorder or substance abuse disorder diagnosed by a psychologist or psychiatrist
• Medication use that significantly alters brain activity
• History of diagnosed learning disability that would interfere with the completion of the cognitive tasks
• Does not report subjective cognitive decline AND/ OR does not perform in the normatively intact range on neuropsychological testing
• Evidence of mild cognitive impairment (MCI) or dementia OR inadequate self-reported performance of instrumental activities of daily living
• Any physical limitation or pragmatic limitation that prohibits attendance at assessment sessions and intervention modules with or without assistive devices
• Presence of MRI contraindications as assessed through the MRI screening form.
• Pregnant or attempting to become pregnant
• Self-reported claustrophobia
• Any regular practice of meditation or yoga (defined as once or more per week) OR Previous participation in a structured mindfulness class (e.g., Mindfulness-Based Stress Reduction, intensive meditation retreat)
• No access to internet or at-home computer with a working microphone and video
• Current enrollment in other RCTs examining the efficacy of exercise training, cognitive rehabilitation, stress management, progressive muscle relaxation or other health-based rehabilitation

Single-blind. Any investigators administering assessments will be blind to participants' group allocation.