Showing papers by "Russell M. Church published in 2014"

Amyloid-beta accumulation, neurogenesis, behavior, and the age of rats.

Abstract: The goals of this research were to describe age-related changes in brain biochemistry and behavior, and the relationships between them. The chronological ages of greatest change are particularly important for targeting interventions. In this experiment, 36 Fischer 344/Brown-Norway rats (3, 12, 20, and 30 months old) were trained in lever boxes on temporal discrimination tasks. The greatest response rate decrease and response pattern change occurred between 12 and 20 months. The biochemical results showed that amyloid-beta peptides (Aβ40 and Aβ42) increased with age. The endothelial expression of the Aβ influx transporter (RAGE) also increased, and the expression of Aβ efflux transporter (LPR-1) decreased, with age. The greatest change in the biochemical measures also were between 12 and 20 months. Twenty additional rats were analyzed for stem cell proliferation, and neurogenesis decreased with age, particularly between about 12 and 20 months. These early changes in brain, biochemistry, and behavior provide opportunity for new therapies or prophylaxis.

Integrating timing and conditioning approaches to study behavior.

Abstract: Skinner and Pavlov had innovative ways to measure both the times of their subject's responses, as well as the rate of their responses. Since then, different subfields within the study of animal behavior have prioritized either the rate or timing of responses, creating a divide in data and theory. Both timing and conditioning fields have proven fruitful, producing large bodies of empirical data and developing sophisticated models. Despite their individual successes, a unified view of simple behavior is still lacking. This may be caused, at least in part, by the differential emphasis on data collection and analysis techniques. The result is that these subfields produce models that fit their data well, but fail to translate to the other domain. This is startling given the fact that both subfields use nearly identical experimental procedures. To highlight similarities within the subfields, and provide empirical data in support of this integration, 18 Sprague-Dawley rats were trained on trace, delay, and backward conditioning procedures. Using these empirical data we discuss how traditional summary measures used by these subfields can be limiting, and suggest methods that may aid in the integration of these subfields toward common goals.