We study evolution of the neural substrate of behaviour by highlighting similarities and differences in the brain pathways that organize behaviour in different vertebrates. Investigations relate to the structure and function of brain regions that integrate sensory input and control behaviour in amphibians and fishes. Little is known about the functional organization of behavioural pathways in these animals. Comparison with the better known but highly complex mammalian brains could help elucidate the basic pathways and mechanisms organizing behaviour. Our approach is threefold: 1) behavioural experiments; 2) anatomical methods to describe the architecture of brain pathways; 3) measure of brain activity by direct recording of electrical activity or labelling of indirect markers of neuronal activation. Additionally, recent research efforts have begun to unravel how plastic organs, such as the brain, are influenced by ecology and environmental factors in wild fish.
Neurobiology of learning in amphibians
Important similarities have been noted between the organization of the amphibian telencephalon and the mammalian limbic pathways involved in the regulation of motivated behaviour. We study the brain substrate of behavioural flexibility and habit learning in amphibians within a comparative perspective. For that purpose, protocols of appetitive and aversive conditioning are established using amphibians in the laboratory. These conditioning protocols are then adapted for methods of functional neuroanatomy, which measure brain activity indirectly. By doing these experiments, we hope to clarify which regions of the brain as well as which neurotransmitters and neuromodulators take part in learning and motivation processes in amphibians. The information gleaned from studies of amphibians can then be compared to the situation in other vertebrates to infer evolutionary trends.
Neuroecology of teleosts fishes
Along with the lab of Dr. Kevin McCann, we have recently begun a collaborative research effort focused on the relationship between organ morphology (brain, sense organs, heart) and ecology in teleost fishes. Teleosts display abundant, lifelong brain neurogenesis and cardiac remodelling, allowing them to fine-tune the morphology of organs critical for their performance in a dynamic environment. These investigations aim to get a better picture of what a fish needs to occupy its position in a food web and how resources are allocated for organ growth in individuals.
Olfactory neurobiology in plethodontid salamanders
Most amphibians possess both a vomeronasal (accessory olfactory) and a main olfactory system. The vomeronasal pathway in salamander displays uniquely direct connections to brain regions involved in behavioural control and mediates the detection of a variety of biologically relevant chemical cues. Thus, it appears a good model pathway to study how the nervous system processes sensory information from molecules to behaviour. We study behaviour and brain responses following the delivery of olfactory stimuli to the vomeronasal organ of salamanders. Electrophysiology can be used to establish how bioelectrical signals are processed from the vomeronasal sensory neurons to the behavioural control centres of the brain.