Infection of rats with Toxoplasma gondii enhances impulsive choice accompanied by an increase in dopamine content

Abstract

Toxoplasma gondii (T. gondii) is a protozoan parasite that is well-known for its ability to cause behavioral manipulations to its hosts such as sensory attention deficits and prolonged reaction times. [1] In rats infected with T. gondii, they develop an unusual attraction to cat odors and thereafter, transmit the infection to the felines during prey and predator process as solely felines contribute to the survival of T.gondii by shedding off their parasitic oocytes through their feces. T.gondii is then exposed to other mammalian species, including humans. Studies have proved that the infection of T. gondii leads to an increase in dopamine quantity in the rats’ brain [2], as the parasite synthesizes a tyrosine hydroxylase that converts the amino acid tyrosine to L-DOPA, the precursor of dopamine [3]. Our work which involved many literature consolidations has been in agreement with the hypothesis that dopamine quantity increases in the brains of infected rats. They have also been tested for impulsive behaviour and revealed that dopamine surge leads to more risky performances. We then further study the anatomy of the rats’ brain in order to correlate the degree of impulsivity in each brain region.