Neurobiological Mechanisms of Aging and Stress on Prospective Navigation
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age65-80
SponsorGeorgia Institute of Technology
About this trial
Two hallmarks of both healthy aging and age-related disease are 1) memory and navigational deficits, particularly in orienting towards goal locations and planning how to navigate to them, and 2) increased susceptibility to stress and altered regulation of the stress response. However, there are marked individual differences in these age-related changes. The investigators' proposal will help characterize factors that contribute to this variability.
Participants will be pseudorandomly assigned to stress-manipulated or control groups. The investigators will give both groups a novel immersive navigation task, validated by the PI in healthy young adults. This paradigm gives participants the opportunity to either (a) flexibly draw on spatial memory in order to plan efficient routes to goal locations, or (b) fall back on inefficient, but cognitively less-demanding, stimulus-response associations (i.e., habits). Using neuroimaging and behavioral measures, the investigators' protocol will test whether experimentally-induced stress leads individuals to bring fewer details about future locations to mind when route planning, and whether such restricted prospective thought ultimately biases participants towards relatively inflexible, habitual actions.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
adults 65-80
U.S. citizens or permanent residents
who speak fluent English
willing to come to Georgia Tech to participate in group testing sessions.
Disqualifiers
Individuals will be carefully screened using IRB-approved procedures for safety contraindications to MRI and electrical shock stimulation
(e.g., metal or electrical implants, heart arrhythmia, or medication affecting the cardiovascular system [e.g. beta-blockers]).
Epilepsy
Dementia
Trial design
Design model
Parallel
Treatments tested in this trial
Anticipatory psychological stress
BehavioralUnpredictable delivery of low-level electrical stimulation to left ankle periodically throughout psychology tasks (virtual navigation). Established procedure for inducing anticipatory stress.
Treatment groups
85 Participants
are divided into 2 treatment groupsGroup A: No-stress control groupNo intervention 0 interventions
Group B: Stress groupExperimental treatment 1 intervention
Trial outcomes
Primary outcomes
1
Behavioral probability of taking a shortcut between control and treatment groups
Probability of taking a virtual navigation shortcut on an fMRI task trial, compared between stress and control groups. Measurement tool: objective categorical measure (no scale) reflecting proportion of trials in which participants traverse the shortcut road or, alternatively, the familiar (longer) road in a virtual environment.
Time frame
Approximately 1.5 years2
fMRI activation level between control and treatment groups
Network activation levels (across frontoparietal, hippocampal, and striatal memory network) during fMRI task trials, compared between stress and control groups. Measurement tool: fMRI activity level. Scale: continuous activity level estimates from fMRI.
Time frame
Approximately 1.5 years3
Neural memory representation reactivation between control and treatment groups
Memory reactivation levels in neural activity patterns during fMRI task, compared between stress and control groups. Measurement tool: Machine learning algorithm trained to decode fMRI patterns across voxels. Scale: algorithm success at classifying fMRI patterns according to the correct location memory for a given fMRI task trial
Time frame
Approximately 1.5 yearsSecondary outcomes
1
Relationship between fMRI activity level and behavioral probability of taking a shortcut.
A linear regression will relate continuous network activity levels (Outcome measure 2) across participants with proportion of virtual navigation shortcuts (shortcut vs familiar route; Outcome measure 1). Measurement tool: fMRI and objective categorical measure of route choice behavior during fMRI task.
Time frame
Approximately 1.5 years2
2. Salivary cortisol (stress hormone) response difference between stress and control participant groups.
A two-sample t-test will compare stress hormone levels (cortisol from saliva sample) between the stress and control groups. Measurement tool: cotton swab (salivette) assay of de-identified hormone levels in saliva during fMRI task.
Time frame
Approximately 1.5 yearsSponsors and contacts
Click on the lead sponsor to view all of their trials.
Georgia Institute of Technology
Lead sponsor
National Institute on Aging (NIA)
Collaborator
Source ClinicalTrials.gov