A positron-emission tomography (PET) study has revealed that the response of the brains of older and younger adults is different to thirst.
This study disclosed the differences between younger and older adults in positron-emission tomography measurements of brain activations to thirst and satiation.
The study was conducted by researchers at the Health Science Center, the Southwest Foundation for Biomedical Research in San Antonio, the Howard Florey Institute at the University of Melbourne, Australia, and the Baker Heart Research Institute, also in Australia.
The pattern of brain activations during thirst and satiation was found to be different in twelve healthy subjects in their 60s and 70s than in 10 healthy subjects in their 20s who drank the same amounts and underwent imaging with positron-emission tomography (PET).
Dysfunction in activated neural regions could help explain why older adults show the dangerous tendency toward reduced drinking in response to dehydration.
The researchers conducted a series of studies to record brain activations to basic physiologic necessities such as thirst, body temperature regulation, air hunger and pain relief.
"These are self-sensations that have very strong motivational power," said Peter T. Fox, M.D., professor and director of the Research Imaging Center at The University of Texas Health Science Center at San Antonio.
PET imaging measures brain function rather than picturing anatomical structure.
In this study, researchers indicated a less robust cerebral blood flow in a region called the anterior midcingulate cortex in the older study participants compared to the younger subjects.
This PET study of thirst was published in the latest Proceedings of the National Academy of Sciences Online Early Edition.