What was a significant finding from Decoursey’s research on the SCN?

Decoursey's research highlights the critical role the suprachiasmatic nucleus (SCN) plays in regulating circadian rhythms and its importance in the behavior and survival of organisms. A significant finding is that disruptions to the SCN connections can impact an organism's vulnerability to threats in their environment, such as increased predation. This was evidenced in studies where animals with disrupted SCN function exhibited altered behavioral patterns, making them more susceptible to predators due to irregular activity cycles.

In contrast, other options provided do not align with the established findings. While disruption of the SCN is linked to sleep disorders, the emphasis of Decoursey’s work is more profound in its implications for survival than just sleep regulation. The importance of SCN in hormone regulation is also noted but not as a primary focus of Decoursey’s findings. The notion that the SCN plays no role in sleep-wake cycles contradicts the significant body of research demonstrating its essential function in these biological rhythms. Thus, the assertion that the removal of SCN connections can increase predation reflects a key aspect of how circadian rhythms influence an organism's overall fitness in the wild.