The primary focus of the Language and Aging Lab is to investigate the ways in which language processing differs between younger and older adults at both the behavioral and neural level. Past research has demonstrated that while language comprehension is generally well-maintained with increasing age, older adults often experience declines in language production abilities, which can be characterized by slower speech rates, slower and less accurate object naming, and increased frequency of tip-of-the-tongue states. Given this, many of the current projects in our lab seek to more fully explore age differences in language production, using functional magnetic resonance imaging and a variety of behavioral paradigms to better understand the factors that may contribute to these production deficits. For example, we are currently investigating the ways in which the presence of distracting information during picture naming affects activation of brain regions that support language production. This particular project uses a Picture Word Interference paradigm to find support at the neural level for some of the theories that have traditionally been used to explain age differences in language production (e.g. Inhibition deficits and transmission deficits). A second ongoing project seeks to explore the way in which task difficulty may contribute to age differences in language production. Using a novel modification of the Go/No-Go task which participants complete inside the scanner, we are able test whether increasing task demands related to picture naming differentially affects older adults’ ability to recruit core language processing regions when compared to younger adults. A third project examines age differences in multisensory processing. Using a behavioral paradigm that utilizes the McGurk effect, we are working to provide neural evidence to support the behaviorally-based theory that age-related declines in sensory processes (i.e. audio and visual processing) can be compensated for by increased efficiency of multisensory processing.
Changes in White Matter Integrity and its Behavioral Correlates in Older Adults
Diffusion Tensor Imaging (DTI) is a neuroimaging technique that tracks the movement of water molecules through the brain. The direction in which water molecules travel is determined in part by the orientation of fiber tracts in the brain. Thus, through the use of DTI, researchers can better understand the structure of the brain and how different parts of the brain are connected to each other. Because brain structure has been shown to change with age, it is particularly important to understand how such changes may affect various aspects of cognition.To this end, we collected DTI data in both older and younger adults, as well as behavioral measures that incorporate tests of speed, recall, verbal fluency, and other executive functions. Our current project seeks to investigate the relationships between age, brain structure, and cognitive functioning.
Healthy aging is accompanied by changes in fine motor control that compromise dexterity and changes in cognition that may compromise activities such as driving, cooking, and navigation. Previous work suggests that such changes in motor control and cognition may be related to one another and to brain structure (Holtrop, Loucks, Sosnoff, & Sutton, 2014; Romero-Garcia, Atienza, & Cantero, 2013), white matter connectivity ( Davis et al., 2009; Madden et al., 2009), brain function (Dennis, Bowman, & Peterson, 2014; Dennis & Cabeza, 2011; Dennis, Kim, & Cabeza, 2007; Rizio & Dennis, 2014), and genetics (Dennis et al., 2010; Glahn et al., 2013). The goal of this research is to determine the relations between cognition, grip force control, genetics, brain structure, and brain function in healthy older adults. Although there is a wealth of literature in each of the above-mentioned disciplines and its relation to healthy aging, this represents the first investigation to combine measures of cognition, grip force control, genetics, and brain structure and function in healthy older adults.