Neural Representations of Memory Transformation (MEM_TRANS)

Investigators overarching goal is to provide evidence for the link between altered spatiotemporal (where and when) neural mechanisms and the extent of changed memory maintenance in healthy older adults and to identify potential neural markers of compensatory function (cognitive resource). Investigators preliminary studies suggest that healthy older adults, compared to younger adults, benefit behaviorally from increased coupling between frontal and parietal brain waves when retrieving and updating well-consolidated visuomotor sequence memory via stronger top-down cognitive control of memory maintenance. Thus, Investigators central hypothesis is that the dynamics across cortical and subcortical regions (i.e., spatiotemporal representations) during transitions between different levels of memory stability indicate the efficiency of memory maintenance. The rationale is that while temporal and spatial neural signatures carry distinct mechanistic information, the joint definition of spatial and temporal representations will allow the differentiation of compensatory versus neurodegenerative mechanisms.

To investigate the spatiotemporal neural dynamics during memory maintenance mechanisms, healthy older adults will practice a computer-based online visuomotor sequence learning task over consecutive days until reaching a performance plateau. At the performance plateau, participants will undergo concurrent electroencephalography and magnetic resonance imaging (EEG-fMRI) while being exposed to a behavioral interference intervention to perturb the stability of the previously stored memory trace to extract spatiotemporal neural dynamics during these transitional states. Additionally, participants will undergo an additional brain scan to quantify aging-related neurodegeneration based on grey- and white-matter integrity, cerebral perfusion, and resting-state connectivity. Cognitive functioning and putative confounders of learning and memory will be quantified with standardized assessments. The experimental procedures include an individual number of daily computer-based sessions of task practice at home, and two lab visits including questionnaires, neuropsychological testing, and two MRI brain scans distributed over approximately two weeks.

Eligibility Criteria:
Inclusion Criteria:

* Age 18 years or older (80 of the final sample will be ≥60years of age)
* Cognitively unimpaired, ambiguous, or mildly impaired cognitive function, defined as a score of ≥18 in the Montreal Cognitive Assessment (MOCA).
* No previous stroke, brain tumor, neurodegenerative disease, or trauma to the head
* Ability to give consent for study participation
* Ability to perform a computer task requiring responding to visual cues and typing on a standard computer keyboard with both index and middle fingers for 30 minutes daily.

Exclusion Criteria:

* Inability to use both index and middle fingers to type on a standard computer keyboard
* Dementia defined as a score of \<18 in the Montreal Cognitive Assessment (MOCA)
* Uncorrected vision, hindering perception of visual cues presented on a standard computer screen
* Medication use at the time of study that may interfere with learning, including but not limited to carbamazepine, flunarizine, sulpiride, rivastigmine, and dextromethorphan.
* Neuromuscular disorders that affect fine motor control of the hands.
* Presence of neurological or psychiatric disorders
* Presence of scalp injury or disease
* Prior intracranial surgery
* Prior brain radiotherapy
* Prior history of intracranial tumor, intracranial infection, or cerebrovascular malformation
* Metal in the head or neck
* Contraindications to MRI (such as severe claustrophobia, implanted medical devices)