Research

The lab pursues three main research lines:

Anatomy of the behavioural brain in amphibians

In mammals, it is thought that brain regions organized as paired longitudinal columns in the preoptic area, hypothalamus and ventral brainstem exert control over the motor aspects of motivated behaviour, with distinct regions dedicated to ingestive/reproductive/defensive and exploratory/foraging behaviours. These regions receive diverse inputs, notably from many parts of the telencephalon. However, the complexity of connections is such that a synthesis is difficult. Amphibians possess simpler brains, but little is known about the functional organization of the behavioural pathways in these animals. Comparison of amphibian brains with the better known but highly complex mammalian brain could help elucidate the basic pathways and mechanisms organizing behaviour. Work in the Comparative Neurobiology Lab attempts to establish the anatomical and functional subdivisions of the brain regions involved in behavioural control in selected amphibian species.

Neurobiology of learning in amphibians

Recent studies have implicated the telencephalon in behavioural flexibility in amphibians. Important similarities have also been noted between the organization of the amphibian forebrain and the mammalian limbic pathways involved in the regulation of motivated behaviour. We study the brain substrate of behavioural flexibility in amphibians. For that purpose, we establish protocols of appetitive and aversive conditioning in amphibians. Once successful, these conditioning studies are adapted for methods of functional neuroanatomy, which measure brain activity indirectly.

Olfactory neurobiology in plethodontid salamanders

Olfaction plays a major role in the behaviour of amphibians. Most amphibians possess both a vomeronasal (accessory olfactory) and a main olfactory system. Our champions of olfaction are the terrestrial plethodontid salamanders! They possess a well developed vomeronasal system alongside the main olfactory system, and they use a distinct behaviour called 'nosetapping' to bring molecules in contact with their vomeronasal epithelium. The vomeronasal pathway in salamander displays uniquely direct connections to the behavioural brain 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. Most notably, electrophysiology is used with the objective of establishing how bioelectrical signals are processed from the vomeronasal sensory neurons to the central regions involved in behavioural control. The arrow points to a nasolabial groove leading to the right nasal opening in a red-legged salamander. The grooves pick up soluble cues when the salamander 'taps' its nose on the ground. The cues are then funnelled to the naris and subsequently to the vomeronasal epithelium inside the olfactory chamber.