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The neurobiology of natural reward
The reward system is an essential element involved in motivation. Many mental disorders like addiction, obesity, or depression can occur when this system is not functioning properly. Our research uses sexual behavior as a natural incentive-driven behavior to study the fundamental principles behind the motivational system in rats. Different brain areas become activated during different phases of sexual behavior, suggesting that different mechanisms are involved in the different parts of sexual behavior. Therefore, in order to complete the full cycle from sexual motivation, copulation and ejaculation, certain brain areas should switch from an active state into an inactive state, or the other way around.
The research team led by Dr. Snoeren (behavioral and translational neuroscience) aims to investigate the neural network of natural reward, measured by sexual motivation and behavior. We are especially interested in the regulation of the switch from an intrinsic motivational state into the execution of copulatory behaviors. To reach this goal, the team employs a combination of pharmacological, chemogenetical and behavioral approaches. The future goal is to introduce new techniques that allow to study specific neural activation and neurotransmitter release within the synapses of relevant projections on a narrow and precise temporal scale.
Relevant candidates should have a background in behavioral neuroscience with a strong emphasize on novel, advanced neuroscientific techniques.
The neurobiology of natural reward
Background
The reward system is an essential element involved in motivation. Many mental disorders like addiction, obesity, or depression can occur when this system is not functioning properly. Our research uses sexual behavior as a natural incentive-driven behavior to study the motivational system in rats. Because sexual behavior requires an intrinsic state of motivation and a natural extrinsic incentive, the motivational/reward system can be studied in a more ecological way than with other rewards like excess sugar or drugs. This allows us to study both motivation and the transition to actual consummatory behavior in this model for natural reward. The research on sexual behavior can thus be used to unravel the complexity of a natural reward system and generate a better understanding. This can help finding treatments for disorders linked to reward.
Sexual behavior can mainly be divided into three phases: the introductory, copulatory, and the ejaculatory phase. Most research investigating rat sexual behavior focuses on the copulatory and ejaculatory behavior, while the introductory phase is often neglected. The sexual drive during the introductory phase and the transition to the copulatory phase is the most important indicator for sexual motivation. It is, therefore, essential to include all these phases in research on sexual behavior as a natural reward.
Interestingly, different brain areas become activated during different sexual phases, suggesting that different mechanisms are involved in the different parts of sexual behavior. As a consequence, this implicates that in order to complete the full cycle of sexual behavior from sexual motivation, copulation and ejaculation, certain brain areas should switch from an active state into an inactive state, or the other way around.
Project and approaches
The key goal of our research is to unravel which pathways in the brain are involved in natural reward, measured by sexual motivation and behavior. We are especially interested in the regulation of the switch from an intrinsic motivational state into the execution of copulatory behaviors.
So far, more traditional lesion or pharmacological studies may reveal the structures and projections needed for a behavior, but it has been proven difficult to unravel the precise connections or nature of these projections that are involved (lesions tend to affect both the direct and indirect pathways). In our current research, we use chemogenetics (DREADDs) to circumvent most of these problems. Functional properties of a specific projection can be investigated by chemogenetics, and will thereby generate more insights into the role of the communication between brain areas in sexual motivation and behavior.
Future strategies
In the future we are interested in investigating the relevant projections needed for the motivational and copulatory facets of the sexual cycle in more detail. By implementing new techniques in our lab (in-vitro and in-vivo), we would like to study the specific neural activation and neurotransmitter release within the synapses of relevant projections on a narrow and precise temporal (millisecond) scale. The goal is to gain more knowledge about the mechanisms driving the switch between the behaviors.
Research environment
The research will be conducted in the research group of ‘Behavioral and translational neuroscience’ at the Department of Psychology of the UiT Arctic University of Norway. This research group consists of Dr. Eelke Snoeren (PI), Roy Heijkoop (research engineer), Patty Huijgens (PhD student) and Indrek Heinla (postdoctoral fellow). We are an international group with backgrounds in various disciplines such as neuroscience, medicine, pharmacy and psychology. Besides, the research group has close international collaborations with Prof. Dr. Louk Vanderschuren and Dr. Heidi Lesscher from Utrecht University in the Netherlands, Dr. Jocelien Olivier from the University of Groning in the Netherlands, and Dr. Jaime McCutcheon from the University of Leicester in the United Kingdom.
We are looking for a highly motivated and curiosity-driven postdoctoral fellow. Experience in behavioral neuroscience with the use of state-of-the-art techniques would be highly appreciated. In addition, we prefer applicants with good publishing track records corresponding to the duration and depth of their research experience. We expect the candidate to proactively contribute to multiple aspects of the project with their own ideas.