The Effectiveness of MRI in Diagnosing Osteoarthritis as Compared to Evaluative Cadaveric Dissection

Presenter: Katherine Kennedy − Human Physiology

Faculty Mentor(s): Jon Runyeon

Session: (In-Person) ) Oral Panel—Neuron & Cognition

Osteoarthritis (OA) is the leading cause for chronic disability in the U.S, affecting over 32 million adults nationwide. Although there is no cure for the age-related disease, early detection and diagnosis is crucial in providing individuals with treatment that will improve joint function, health, and overall quality of life. With what is often said to be the gold standard of OA diagnosis, Magnetic Resonance Imaging (MRI), researchers have studied the tool’s methodological accuracy through comparing it to other widely used instruments, such as X-rays. However, all imaging methods offer indirect visualization of the pathological condition, whereas analysis of the joint cartilage itself would offer a direct way of evaluating the disease. The purpose of this study was to assess MRI effectiveness in the diagnosis of osteoarthritis through visualization of common pathological features in the knee both indirectly, using MRI, and directly through evaluative dissection of the cadaveric knee joint. It is hypothesized that the observations and measurements drawn from the direct dissection of the joints will convey clearer indications of OA and the true grade of its severity more so than MRI will through the minimal OA evidence picked up indirectly through magnetic signals. This will dismiss MRI as the gold standard for OA diagnosis and will pave the way for future research on discovering new, effective methods for early detection and accurate diagnosis of the common joint disease.

Dissociating the Time Courses of Two Neural Mechanisms Underlying the Rod-and-Frame Illusion

Presenter: Ernestine Brannon − Psychology

Faculty Mentor(s): Paul Dassonville, Jeffrey Peterson

(In-Person) Oral Panel—Neuron & Cognition

Witkin and Asch (1948) developed the rod-and-frame illusion (RFI) to investigate how the visual system uses context to determine an object’s orientation by providing a distorted visual field and examining its effects on orientation judgments. The RFI is thought to be driven by a combination of local and global mechanisms. The local mechanism is brought about by low-level visual properties causing an orientation contrast effect between the rod and edges of the frame. The global mechanism is the product of a compromise between the visual and vestibular systems. In this study, we examine the time courses associated with the local and global mechanisms thought to underlie the RFI. We also examined the effect on illusion magnitude when we isolated the global mechanism.Participants performed a two-alternative forced choice task where they made orientation judgments (clockwise or counterclockwise of vertical) of the RFI stimulus and a new type of stimulus, the knob-and-frame illusion (KFI), designed to isolate the global effect. We varied stimulus onset asynchronies to determine when the frame begins to bias perception of vertical and when the illusion reaches its full magnitude for each stimulus type. As predicted, we found the RFI had a greater illusion magnitude than the KFI. We found that the KFI and RFI unfolded under similar time courses. The influence of the frame began with negative SOAs and built until reaching a plateau early in the positive SOAs.