OUR TWO BIG QUESTIONS:
- How do brain regions involved in memory control eating behavior?
- Does impaired memory/hippocampal function cause the development and/or maintenance of diet induced obesity?
We approach our questions with two general strategies:
- Manipulate neural activity e.g., with drug infusions or optogenetics
- Measure the impact of ingestion on brain and behavior
Our research typically involves obtaining measures of learning and memory, synaptic plasticity, energy intake, body weight, body fat, and biochemical measures from brain, blood, and peripheral organs such as the liver.
We currently focus on how hippocampal activity, which is traditionally associated with episodic memory, modulates energy intake in rodents. We hypothesize that dorsal hippocampal neurons form a memory of a meal and inhibit future intake, both in terms of delaying the initiation of the next meal and limiting the amount consumed during that meal. For more details regarding this hypothesis read our recent review (Parent et al 2014).
To the best of our knowledge we are the first to implicate dorsal hippocampal neurons in energy intake (Henderson et al 2013). These findings indicate that manipulations that specifically impair hippocampal function increase energy intake. In life, many situations such as stress and illness impair hippocampal function. For example, we have found that one episode of pain on the day of birth produces long-lasting deficits in hippocampal function that last at least until middle-age (Henderson et al 2015). We have also shown that overeating fat and sugar and non-alcoholic fatty liver disease impair hippocampal-dependent memory (Darling et al 2013; Ross et al 2009; Ross et al 2012; Ross et al 2013).
Collectively, these findings have led us to further hypothesize that life events, such as stress or overeating, impair hippocampal function, which in turn causes more eating. For more details about this vicious cycle read our recent review (Parent et al 2014).
This research is supported by the National Science Foundation and the Georgia State University Brains & Behavior Program.