Meeting Abstract
Our world is changing rapidly, and with it, so are its inhabitants. How do these rapid changes affect the brain’s ability to help organisms navigate through new environments? We evaluated the effects of rapid environmental change on the brain using the Lesser Earless Lizard (H. maculata) as a model. We compared the medial cortex- a structure important for spatial navigation and spatial memory- of two populations living in adjacent yet physically distinct environments. Specifically, we asked whether differences in habitat complexity were associated with changes in corresponding neural structures. The first environment, the White Sands formation in southern New Mexico, exhibits markedly reduced physical and biological complexity relative to the surrounding dark soil habitat of the Chihuahuan desert. We found neuroanatomical differences between the two populations. Specifically, lizards in the less complex environment had smaller medial cortices in relation to overall brain size than those in the more complex environment, consistent with our expectation that reduction in medial cortex area is related to a reduced need for spatial navigation and spatial memory. In the more complex environment, males had larger medial cortices than females, also consistent with the fact that male lizards are often exposed to more habitat complexity than females. By integrating the fields of neurobiology, ecology and evolutionary biology, we have uncovered a mode of neuroanatomical selection in which organisms with less need for use of their medial cortex “lose it”, or experience a reduction in the area it encompasses within the brain. Overall, our work demonstrates that environmental change can affect brain structure and these changes in neuroanatomy can occur rapidly.
