Speaker
Description
The heart and brain are bidirectionally connected, integrating autonomic functions such as heart rate and blood pressure with cognitive and emotional processing. At the interface between the two lies the locus coeruleus (LC), a primary source of norepinephrine in the brain with connections to the autonomic nervous system. However, the LC is particularly vulnerable to neurodegeneration even in healthy aging. LC-sensitive MRI studies indicate an inverted U-shape pattern in LC signal intensity, peaking around 60 years of age, followed by a decline associated with reduced structural integrity likely from potential neuronal loss. This decline shows considerable inter-individual variability, which may reflect differences in autonomic nervous system activity that also exhibits age-related changes. Previous research in older adults has associated higher LC structural integrity, as measured by MRI signal intensity, with lower heart rate variability (HRV), a key indicator of parasympathetic activity. However, the interplay between LC structural integrity, HRV, and aging, remains unclear. To address this gap, Study 1 will investigate the bidirectional relationship between LC structural integrity and HRV over time. This longitudinal analysis will assess whether baseline measures of LC structural integrity or HRV can predict changes in the other measure over time, and vice versa. Further, given the shift in autonomic balance with aging—characterized by decreased parasympathetic tone and increased sympathetic activity—Study 2 will examine how LC structural integrity relates to sympathetic indices of cardiovascular activity in older adults. Understanding these complex interactions could provide valuable insights into common mechanisms underlying cognitive decline and autonomic dysregulation in older adults, potentially informing the development of targeted interventions to maintain cognitive and autonomic health in aging populations.
