(783.11) Cadaveric Study of Anatomical Variations in the Limbic System

Poster Board Number: C77
Introduction: AAA has separate poster presentation times for odd and even posters.
Odd poster #s – 10:15 am – 11:15 am
Even poster #s – 11:15 am – 12:15 pm

Rachel Morgan (UT Health San Antonio), Haley Nation (UT Health San Antonio)

The limbic system is a collection of brain structures responsible for affective processing, spatial coding, and certain types of memory. A comprehensive investigation of numerous limbic system components is necessary to thoroughly understand anatomical and pathological differences in individuals with related disorders (e.g. Alzheimer’s disease, depression, etc.). This study examines anatomical variations of limbic system structures including the hippocampus, dentate gyrus, amygdala, and cingulate gyrus. We hypothesize variations in each of the limbic structures studied exist and that these variations will be correlated with one another. This cadaveric study includes the dissection of 47 formalin-fixed brain hemispheres and measurements of pertinent structures. The dentate gyrus, hippocampus, and amygdala are given categorical results: ill-defined, moderately defined, and well-defined; additionally, quantitative measurements are taken for all structures. While previous research has detailed anatomical variations of some of these structures, none have investigated the existence of any relationships between them. Our results indicate variations in the classification of the dentate gyrus (36.2% well-defined, 51.5% moderately defined, and 12.8% ill-defined) and amygdala (57.4% well-defined, 40.4% moderately defined, and 2% ill-defined).  Additionally, there were significant relationships between the length of the dentate gyrus and hippocampus (p=0.004), as well as the width of the amygdala and length of the dentate gyrus (p=0.019). The length of the hippocampus was shown to be dependent on age (p=0.006); increasing age is linked to a shorter hippocampus. These findings are consistent with previously published literature, and this is the first study to highlight the relationships between these variations. The knowledge of these interactions further the understanding of the limbic system and could be used to better understand clinical presentations in future studies.