Project Abstract: A neurocomputational model of age-related differences innavigationFor many individuals navigation skills decline with increasing age particularly for novelenvironments with which the individual is not already highly familiar. Impairments innavigation are particularly evident for those with mild cognitive impairment a significantrisk factor for Alzheimers disease and Alzheimers related dementia (ADRD). Yet ourunderstanding of age-related differences in navigation remains underdeveloped. Thedominant explanation for age-related differences in navigation relates to impairments inthe cognitive map yet the explanatory capabilities of this model are limited particularlyin explaining the heterogeneity of age-related differences in navigation. Here we seekto develop a novel computational model that employs an approximate Bayesianframework to better account for age-related differences in navigation. We focus inparticular on testing hypotheses related to greater reliance on multimodal cue integration(Aim 1) and strategy rigidity (Aim 2) in older adults. These ideas will be tested usinghighly immersive virtual reality in which participants don a head-mounted display andfree ambulate hallways. The experiment in Aim 1 will provide critical tests of ourcomputational model by employing conditions involving both matching and mismatchingvisual and idiothetic (body-based) cues. This will allow us to test Aim 1 and whetherolder adults rely on multimodal integration to a greater extent than younger adults. Theexperiment in Aim 2 will test whether older adults rely on previous trials to a greaterextent than younger adults particularly for matching and mismatching trials. This willallow us to test the extent to which older adults might show strategy rigidity by over-relying on past trials. Aim 1&2 will also allow us to test ideas related to individualdifferences in navigation strategies which can be assessed based on the variability insubject responses within the different conditions tested. Finally we will test a subset ofindividuals with mild cognitive impairment (MCI) to provide initial and exploratory testingof their navigational deficits in our experiments. The outcomes of this project have thepotential to provide a new understanding of age-related differences in navigation bydeveloping a sophisticated and novel computational model that we test in detail withexperiments in immersive virtual reality.