Cecilia Baldoni

Organisms living in temperate climate must deal with seasonal changes in their environment, affecting food availability, plant cover and predation risk. Variable environments promote the expression of cognitive abilities such as exploration, memory and learning, resulting in larger and more complex brains. Moreover, animals have evolved a wide range of strategies (e.g. food caching, migration, torpor, hibernation) to cope with unfavourable seasons, where food scarcity and low temperature can threaten their survival.

The common shrew, Sorex araneus, defies all rules. It does not migrate, and is unable to hibernate or use torpor, and due to the highest known mammalian metabolism has extremely fast fat turnover year-round. Instead, in autumn, this small mammal shrinks its skull, bones and major organs (including the brain) up to 20%, and subsequentially regrows them up to 16% in spring. While this helps them to deal with a decreased resource availability in winter the changes, especially in brain size, are likely to cause compromise.

During my PhD, I will focus on the effects a programmed decrease in brain size can have on cognitive abilities. With repeated in vivo MRI imaging, I will trace changes in size in single brain regions (e.g. neocortex, hippocampus, olfactory bulb) of individual shrews and link them to their performance in cognitive tests (e.g. spatial navigation, odour discrimination, serial learning).