Authors: Sara Knowlton, Sam Chipman, Samantha Stabler, Alex Osmond, Brock Kirwan
Mentors: Brock Kirwan
Insitution: Brigham Young University
The hippocampus is a brain structure involved in recognition memory and pattern separation, or the ability to disambiguate potentially interfering or overlapping memory representations. The Mnemonic Similarity Task (MST) has been used to assess memory specificity by asking participants to encode a series of objects and later perform a recognition memory test with repeated items (targets), similar but not exact repeats (lures), and novel items (foils).
In a single-subject case study, we utilized the MST in evaluating recognition memory over various delays of a subject with anterograde amnesia. Subject MC is a healthy young adult female who underwent a unilateral amygdalohippocampectomy as a treatment for epilepsy. This procedure included the complete removal of her hippocampus in the right hemisphere, which we verified with magnetic resonance imaging. In addition to the MST, we compiled a battery of neuropsychological tests, including the Wide Range Assessment of Memory and Learning (WRAML-3), the Delis-Kaplan Executive Functioning System, and the Wechsler Abbreviated Scale of Intelligence (WASI-II) to more holistically assess MC’s memory deficits.
Preliminary analyses showed significantly lower lure discrimination when compared with control subjects, indicating deficits in pattern separation. Further analysis of MC’s MST results are being conducted to evaluate her broader ability for recognition memory.