Aging- and Learning-Related Changes in Immediate Early Gene Expression

Due to the growing portion of the population that is expected to reach old age in the coming years, incidences of aging-relatedneurodegenerative disorderslike Alzheimer\u27sdiseaseare also expected to become more prevalent.To determine areas of the brain that may be functionally impaired, the expression of immediate early genes (IEGs) such as c-Fosand Zif-268were studied, because expression of these in abrainregion can indicate aging-related changes in activity. Tostudylearning- and aging-related changes in the expression of IEGs, immunohistochemistry was usedtolabel IEGs.Thus, this study is designed to explore the relationship between aging-related changes in cognitive function and neuronal activity during learning and memory.In thepresent experiment, rats were subjected to either trace fear conditioning, trace fear conditioning with extinction, pseudo conditioning, or were left naive and thus remained in their home cage.Prior analyses illustrated that adult rats showed increased levels of c-Fosand Zif-268 in the prelimbic and infralimbic medial prefrontal cortex after training, while this increase is less pronounced in aged animals. Additionally, training resulted in increased expression of c-Fosin the lateral amygdala for all age groups, while no changes were observed after extinction for aged or middle aged rats. No discrepancy between age groups and their ability to acquire the training was found, but variation in IEG expression suggests differences in brain function between groups. Ongoing research is studying the expression of these IEGs in the dorsal and ventral hippocampus. Studying aging-related changes in IEG expression in conjunction with their learning-dependent changes allows for the identification of how information processing changes across the lifespan