Integrated Calendar

Triterpenoids are a diverse class of secondary metabolites with important roles in plant defense, stress tolerance, and communication. In this study, we investigated the diversity and evolution of triterpenoids in plants using a combination of molecular, biochemical, and evolutionary approaches. Our results showed that various plant families have exploited the same evolutionary mechanism of molecular hijacking, whereby proteins involved in cell wall biosynthesis are co-opted for the production of triterpenoids. This process led to the formation of metabolons, which are protein complexes that facilitate the channeling of intermediates between enzymes in the biosynthetic pathway. Our study shows that the another gene involved in the pathway has undergone duplication and evolved to produce different types of metabolites in different Solanum species. Our findings provide insight into the complexity of plant secondary metabolism and the mechanisms underlying its evolution.

My lab’s focus in recent years has been split between development of ultra-high resolution fMRI at high field and the exploration of more sensitive yet robust methods to find all the salient transients and trends in the signal. High field, high resolution fMRI relies heavily on the acquisition technology and the functional contrast used as well as unique processing approaches that segment, as well as possible, cortical layers for analysis. Our fMRI time series analysis research relies on creative paradigm design in conjunction with tailored processing methods that strike a balance between casting a wide net for potentially informative signals and applying just enough modeling to make sense of the data. Our goal is to use fMRI to see neuronal activity and capture neural correlates of behavior that have previously been elusive to more standard approaches. 
Specifically, for our high resolution fMRI work, I will describe experiments demonstrating layer-specific activity in motor, somatosensory, and visual cortex that changes with tasks that modulate the hypothesized input and output cortical communication. In our lab, we perform layer fMRI using a functional contrast called VASO (vascular space occupancy) that is sensitive to blood volume changes in micro vessels - having more specificity than BOLD with only a small tradeoff in sensitivity. Layer fMRI has the potential to provide cortical hierarchy information and communication directionality based on the understanding that feedforward connections terminate predominantly in middle layers and feedback connections terminate in predominantly upper and lower layers. Hence by determining activation location across cortical depth, one can infer whether the activation is feedforward or feedback. I will also demonstrate how the use of resting state connectivity in conjunction with layer fMRI is able to discern such cortical hierarchy in visual areas. Lastly, I will also show examples of applications of layer fMRI in frontal cortex during a working memory task. In addition, I will show our high resolution fMRI work that has allowed us to discern a new digit organizational pattern in motor cortex. 
For our time series work, I will show our recent results in using connectivity-based decoding for identifying, in an unsupervised manner, tasks being performed. In addition, I will show an application of naturalistic stimuli and inter subject correlation to characterize personality trait and language skills of individuals. Lastly, changes arousal state during scanning has been viewed as both a confound and opportunity. I demonstrate our effort to further characterize the temporal and spatial signatures of arousal state changes in fMRI time series.