Research | Lambert Behavioral Neuroscience Laboratory
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Neurobiology of Parental Responses

california mouse maternal rat

California Deer Mouse Dad & Pup

Maternal Rat


Working with my colleague Dr. Craig Kinsley, we have conducted extensive work exploring how being a mom changes the brain in adaptive ways so that she can take better care of her offspring, protecting her genetic investment.  Maternal rats exhibit enhanced spatial learning in foraging tasks, bolder exploratory responses, enhanced motor agility, more efficient hunting skills, and more focused attention toward salient cues in the environment.  Along with these behavioral adaptations, neuroanatomical changes have been observed in the hippocampus.


We use a comparative species approach to investigate paternal behavior; specifically we compare the California deer mouse (Peromyscus californicus), a species known for it’s paternal responsiveness, with a close cousin known as the common deer mouse (Peromyscus maniculatus), a species that ignores its offspring and offers no help to  the mouse mom.  Recently we have worked on mapping the paternal brain circuit by creating family reunion scenarios and investigating the presence of fos-immunoreactive cells when the dads are reunited with their offspring.  Our results implicate an overlap between several maternal and paternal brain circuits---additionally, the neuropeptides oxytocin and vasopressin play critical roles in the onset and maintenance of paternal responsiveness in the California deer mouse. 

Peromyscus Mouse Paternal Behavior Video

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Check out this short video about our research results comparing two species of Peromyscus mice and their paternal parenting skills. (Download Video Here)


Stress and Coping

rat removing tail clip rat swimming

Rat trying to remove tail clip

Rat swimming in a tank

Let’s face it; we can’t avoid stress in our lives.  The bad news is that chronic stress is toxic to our brains and overall health—the good news is that stress can be mitigated when adaptive coping strategies are used.  Our laboratory has identified predisposed coping strategies in the rats—active, passive and flexible coping strategies.  Research thus far suggests that flexible coping strategies are healthier than the more consistent passive and active copers.  Additionally, gaining control over the environment via effort-driven reward training (digging up froot loops on a daily basis as opposed to just receiving them regardless of effort) enhances resilience over the effects of chronic stress.  These models have been associated with neurobiological characteristics of resilience such as increased DHEA and Neuropeptide Y.  Thus, although we have little control over our biological predispositions when it comes to stress responses, we may be able to modify our response systems by engaging in “work” that establishes clear associations between effort expended and gained rewards.  It looks like being a “trust fund rat” may be costly to our emotional resilience…so, get to work!

Enriched Environments:
Natural vs. Artificial

standard enriched environment natural enriched environment

Rat in standard enriched environment

Mouse in natural enriched environment

We have known for quite some time that enriched environments enhance cognitive ability and neuroplasticity.  However, virtually all of this research has been conducted with artificial stimuli, items such as plastic ladders, that were clearly not around when the rat brain was evolving.   We are currently exploring the effects of various forms of natural stimuli included in the enriched environment in both rats and various species of Peromyscus mice.  At this point, our data suggest that cognitive abilities are enhanced in both groups (compared to standard controls) but the naturally enriched animals exhibit more emotional resilience.  So, it looks like both the city and country rats are clever, but the country rats housed in the more naturalistic environment with dirt and sticks may have an emotional advantage.  We still have a lot more work to do in this area!

New Research: Under Construction

Following up on the effort-driven reward work with the rats, our lab is in the process of building a collaboration with Dr. Stan Gehrt (The Ohio State University) and Drs. Roberto Lent and Susana Herculano-Houzel (Universidade Federal do Rio de Janeiro) to investigate two divergent raccoon populations in varied environments:  a park environment where the raccoons don’t have to work for their food and a natural habitat where they forage for food with their sensitive paws.  The raccoon model provides an opportunity to consider the impact of effort-driven rewards in another opportunistic species. More to come!