We maintain several related lines of research, all of which relate to the overarching theme exploring the relationship between naturally-selected behaviors and the underlying neural architecture that support those behaviors. We are particularly interested in examining this relationship within an ecological context, leveraging both field and laboratory experiments, to gain a better understanding of the proximate and ultimate factors that correlate with changes in the neural substrate.
Causes and consequences of variation in the hippocampus of individuals utilizing different spatial strategies
In side-blotched lizards (Uta stansburiana), males occur in three different morphs, each morph using different spatial niches: large territory holders (orange males), small territory holders (blue males) and non-territory holders (yellow males) with home ranges smaller than the territories of small territory holders. Our preliminary study found that large territory holders had larger dorsal cortical volumes relative to the remainder of the telencephalon compared with non-territorial males, and small territory holders were intermediate. These results suggest that some aspect of holding a large territory may place demands on spatial abilities, which is reflected in a brain region thought partially responsible for spatial processing. The overarching goal of this line of research is to examine the genetic, maternal, hormonal, and experiential basis of variation in the volume, number of neurons and neurogenesis in the hippocampus, as well as the associated fitness consequences of variation in hippocampal attributes. This line of research has 5 primary goals: (1) to determine whether changes in hippocampal attributes are genetically encoded and relate to particular allelic combinations, (2) to explore if maternal effects, in the form of estradiol deposition in egg yolk, can cause variation in the hippocampus, (3) to manipulate testosterone in males to ascertain if differences in gonadal hormones mediate underlying changes in hippocampal morphology, (4) to explore if changes in the hippocampus can be induced or enhanced by spatial use experiences, and (5) to assess if natural and lesion-induced variation in hippocampal attributes relate to differential fitness effects, namely survival.
Orange, blue, and yellow morphs (L-R)
The relationship between neural plasticity and an enriched environment
Spatial cognition is important in many ecologically-relevant behaviors and individuals that experience increased demands on their spatial cognitive load also have larger hippocampi, the area of the brain that underlies spatial processing. Clinical research has produced strong evidence that increased environmental complexity can up regulate hippocampal attributes, presumably due to the increased opportunity to engage spatial memory use. However, clinical research does not always reflect what occurs in other animals, nor does it account for variation in naturally-selected spatial behaviors that can differentially modulate the hippocampus. Thus, we seek to examine how environmental complexity impacts the brain in wild-caught lizards.
Side-blotched lizard stock photo https://pixabay.com/en/side-blotched-lizard-head-macro-1550260/