Project Summary: Spatial navigation is an essential task for living a safe, independent life. Spatial navigation
skills decline in normal aging and become progressively impaired in patients with Alzheimer’s disease (AD) 1,2,
severely impacting their daily life function, independence, and health 3. Despite the use of compensatory
navigational tools like signs, maps, and verbal directions, supporting spatial navigation in older adults and
those with age-associated neurodegenerative disease remains a challenge. A major impediment to designing
interventions is the limited understanding of how spatial direction comprehension is affected by the normal
aging process and neurodegenerative disease. The goal of this project is to determine how normal aging
and age-associated neurodegenerative disease affect spatial direction comprehension, and to
elucidate the neural mechanisms underpinning spatial direction comprehension in healthy young and
older adults.
Our primary hypothesis is that spatial direction comprehension is supported as a result of increased
connectivity between regions of the brain dedicated to encoding individual formats (i.e.,visual scenes, arrows,
and words), which will result in specific patterns of impairment among older adults and those with amnestic
mild cognitive impairment (aMCI), a precursor to Alzheimer’s disease. We also hypothesize that the
intraparietal sulcus (IPS) – a region that encodes spatial directions with respect to the navigator's current
facing direction – will function as a hub by computing spatial directions from all representational formats, an
idea which has been supported by recent advances in fMRI. To test these hypotheses, the candidate will
employ converging methodologies from cognitive neuroscience, including advanced functional magnetic
resonance imaging techniques (network neuroscience and functional connectivity), and behavioral assessment
of healthy young adults and older adults, and patients with amnestic mild cognitive impairment (aMCI).
This award will enable the candidate to learn critical new methodologies, which will help uncover the
neural instantiation of spatial direction comprehension. Through research projects and training experiences,
the candidate will apply these methodologies to test new hypotheses and questions about how spatial direction
comprehension deteriorates in older adults and in patients with age-related dementias. This research proposal
will be undertaken at the University of Florida – an elite research institution with access to fMRI, a large
population of older adults with and without age-related dementia, and experts in network neuroscience,
neurology, and cognitive neuroscience. This award will also provide critical preliminary data that will be applied
to an R01 proposal on supporting spatial navigation in older adults and those with Alzheimer’s disease and
related dementias.