LAB PROJECTS

Toxoplasma gondii (henceforth Toxoplasma) is a protozoan parasite of rats. Our research is inspired by loss of fear in animals infected with Toxoplasma. The novelty of our approaches is made possible by a rather serendipitous discovery of infection-enhanced sexual behaviour made by our research group recently.  

Why are Toxoplasma-infected rats attracted to cats?  How does infection affect fear behaviour in animals? We are using infection-driven changes in innate fear to gain insights into the defensive neuro-circuitry.

The loss of fear in infected animals is likely a parasitic manipulation of host behavior because the parasite can only reproduce in cat intestines. We followed this work by showing that effects of Toxoplasma infection were very specific, leaving learning and sensory perception unchanged. Toxoplasma infection reduces fear and anxiety, likely by changing amygdalar substrates. It suggest a phenomenon that is both broader (i.e., beyond rats) and deeper (i.e., blockade of species-specific innate fears) than originally appreciated. In other words, the behavioral effects of Toxoplasma are not merely about rodents and their response to predators. Instead, they may well be about how a number of different species respond to some of their most ethologically fundamental, innate fears.

How do animals decide whom to mate with? How biology determines mating decisions? In our lab, we aim to answer these questions, specifically by studying hormones and pheromones guiding mate choice, using a unique perturbation model.

We have recently reported that this parasite is transmitted during sexual intercourse. In order to increase its transmission, Toxoplasma manipulates physiology of male rats, making them more attractive to females. This manipulation makes it possible for infected males to mate with more females, and parasite to infect greater number of females and progeny. From our lab's perspective, this model provides a previously unavailable model system whereby mate choice is specifically altered. If we can understand how Toxoplasma manipulates mating decisions, we will understand what biological factors guide mate choice in the first place. Utilizing this logic, we study hormones and pheromones essential for communicating male attractiveness to female rats.


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