Linking the why and how of aging; evidence for somatotropic control of long-term memory function in the pond snail Lymnaea stagnalis

Organisms live on a budget; hence they cannot maximize all their activities at the same time. Instead, they must prioritize how they spend limiting resources on the many processes they rely on in their lives. Amongst others, they are thought to skimp on the maintenance and repair processes required for survival in favour of maximizing reproduction, with aging as a consequence. We investigate the biological mechanisms of neuronal aging. Using Lymnaea stagnalis, we previously described various aspects of age-associated neuronal decline and appetitive long-term memory (LTM) failure. In view of postulated trade-offs between somatic maintenance and reproduction, we tested for interactions between resource allocation mechanisms and brain function. We show that removal of the lateral lobes, key regulators of Lymnaea's energy balance, increases body weight and enhances appetitive learning, raising the perspective that the lateral lobes are one of the sites where the why and how of (neuronal) aging meet.