Project Grant F31AG104752

INVESTIGATING THE RELATIONSHIPS BETWEEN 24-HOUR ACTIVITY CYCLE PATTERNS AND COGNITION AND WHITE MATTER INTEGRITY IN AN ADULT LIFESPAN SAMPLE - PROJECT SUMMARY/ABSTRACT AGING IS ASSOCIATED WITH COGNITIVE DECLINE, ELEVATED RISK OF ALZHEIMER'S DISEASE (AD), AND REDUCTIONS IN THE INTEGRITY OF WHITE MATTER TRACTS IN THE BRAIN CRITICAL FOR NEURAL COMMUNICATION. EFFECTIVE TREATMENTS FOR AGE- AND AD-RELATED CHANGES REMAIN LIMITED, HIGHLIGHTING THE NEED TO UNDERSTAND THE ROLE OF MODIFIABLE LIFESTYLE BEHAVIORS FOR PRESERVING COGNITION AND BRAIN HEALTH. GREATER PHYSICAL ACTIVITY, REDUCED SEDENTARY BEHAVIOR, AND SUFFICIENT SLEEP ARE EACH ASSOCIATED WITH BENEFITS TO COGNITIVE FUNCTION AND WHITE MATTER MICROSTRUCTURE. NOTABLY, PRIOR STUDIES OFTEN EXAMINE THESE BEHAVIORS INDEPENDENTLY DESPITE THEIR DEPENDENCE ON ONE ANOTHER AS COMPONENTS OF A 24-HOUR DAY. EMERGING EVIDENCE INDICATES THAT THE BALANCE OF THESE BEHAVIORS, KNOWN AS THE 24-HOUR ACTIVITY CYCLE (24HAC), IS RELATED TO EPISODIC MEMORY AND EXECUTIVE FUNCTION PERFORMANCE. HOWEVER, PREVIOUS RESEARCH IS LARGELY CROSS-SECTIONAL, LIMITED TO OLDER ADULTS, AND RARELY EXTENDED TO MARKERS OF BRAIN HEALTH SUCH AS WHITE MATTER MICROSTRUCTURE. THE PROPOSED RESEARCH WILL ADDRESS THESE GAPS BY EXAMINING CROSS-SECTIONAL AND LONGITUDINAL ASSOCIATIONS BETWEEN 24HAC PATTERNS, COGNITION, AND WHITE MATTER MICROSTRUCTURE ACROSS THE ADULT LIFESPAN, AND BY IDENTIFYING KEY MODERATORS OF THESE RELATIONSHIPS. BASELINE DATA ARE AVAILABLE FROM 303 ADULTS (18-86 YEARS; MEAN AGE = 53 YEARS), WITH 3-YEAR FOLLOW-UP DATA COLLECTION UNDERWAY (CURRENT N = 31). PHYSICAL ACTIVITY, SEDENTARY BEHAVIOR, AND SLEEP WILL BE OBJECTIVELY MEASURED USING WRIST-WORN ACCELEROMETERS AND ANALYZED USING COMPOSITIONAL DATA ANALYSIS TO ACCOUNT FOR THE INTERDEPENDENCE OF 24HAC BEHAVIORS. EPISODIC MEMORY AND EXECUTIVE FUNCTION WILL BE ASSESSED WITH STANDARDIZED NEUROPSYCHOLOGICAL ASSESSMENTS. WHITE MATTER MICROSTRUCTURE WILL BE QUANTIFIED AS FRACTIONAL ANISOTROPY DERIVED FROM DIFFUSION TENSOR IMAGING OBTAINED FROM MAGNETIC RESONANCE IMAGING. AIM 1 WILL EXAMINE THE A) CROSS-SECTIONAL AND B) LONGITUDINAL ASSOCIATIONS BETWEEN 24HAC PATTERNS AND EPISODIC MEMORY AND EXECUTIVE FUNCTION AND EVALUATE WHETHER RELATIONSHIPS VARY BY AGE. AIM 2 WILL EXAMINE THE A) CROSS-SECTIONAL AND B) LONGITUDINAL ASSOCIATIONS BETWEEN 24HAC PATTERNS AND FRACTIONAL ANISOTROPY AND EVALUATE WHETHER THE RELATIONSHIP VARIES BY AGE. EXPLORATORY AIM 3 WILL EXAMINE WHETHER ASSOCIATIONS OF THE 24HAC, COGNITION, AND WHITE MATTER INTEGRITY DIFFER BY GENETIC RISK FOR AD, INCLUDING APOE GENOTYPE AND POLYGENIC RISK SCORE. THE PROPOSED RESEARCH WILL ADVANCE UNDERSTANDING OF HOW MODIFIABLE LIFESTYLE BEHAVIORS JOINTLY RELATE TO COGNITIVE AND BRAIN HEALTH AND CLARIFY THE OPTIMAL BALANCE OF 24HAC BEHAVIORS THAT EXERT THE MOST COGNITIVE AND NEUROPROTECTIVE EFFECTS TO COMBAT AGE-RELATED DECLINE. ADDITIONALLY, THIS WORK WILL HELP IDENTIFY INDIVIDUALS AT HEIGHTENED RISK FOR COGNITIVE AND BRAIN DECLINE WHO MAY RECEIVE THE GREATEST BENEFIT FROM BEHAVIORAL INTERVENTIONS. FINDINGS WILL INFORM COMPREHENSIVE STRATEGIES TO PROMOTE HEALTHY AGING AND PROLONG THE HEALTHSPAN. THE PROPOSAL IS WELL ALIGNED WITH THE MISSION OF THE NATIONAL INSTITUTE ON AGING (NIA) TO EXTEND THE NUMBER OF INDEPENDENT, HEALTHY, ACTIVE YEARS OF LATER LIFE.