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The vomeronasal system is a chemosensory system devoted to processing cues from other organisms. In my talk I will describe a set of studies from our lab that aim to reveal how chemosensory information is represented by neuronal activity in the AOB (accessory olfactory bulb), the first brain region receiving vomeronasal inputs. After reviewing some of our published work on basic aspects of stimulus representations, I will describe unpublished work in which we explore neuronal correlates of behavioral imprinting, reproductive-state dependent processing, and changes in the genetic background of the subject organism. Taken together, these studies point at a high degree of stability of stimulus representations at the level of the AOB. Finally, I will show that despite its presumed role in processing innately relevant cues, the vomeronasal system has considerable capacity to form novel stimulus response associations, providing further support for the idea that responses to innately relevant cues can be dramatically altered as a result of experience.

Cell migration and cell mechanics play a crucial role in a number of key biological processes, such as embryo development or cancer metastasis. Understanding the way cells control their own material properties and mechanically interact with their environment is key. At a more fundamental level, there is need better measure, describe and monitor cell and tissue mechanics before we can formulate testable hypotheses. In this talk, I will report experimental studies on the mechanical response of two different multicellular structures: epithelial monolayers and early embryonic tissues. In both cases, the material exhibits a strong time-dependent response over a broad distribution of time-scales. The combination of mechanical characterisation with biological perturbations offers new insight into the mechanisms exploited by cells and tissue to control their mechanical properties.
This insight is however limited by the lack of consistency in experimental protocols and modelling strategies used in the field. We recently developed a systematic approach to capture material properties from mechanical behaviours and made progress assessing the model’s generality over a broad range of biological systems

Exploring multisensory interactions requires a definition for a single sense. As such, the first part of the talk with focus on the question of "how many senses are there?". Within this discussion, there are interactions between senses that form the mainstay of the multisensory literature. Two factors—space and time—form a foundation for considering when stimuli will be integrated. One series of experiments will focus on the resolution of conflicts between our internal reference frame and the external reference frame by examining the interaction of touch and proprioception in the crossed-hands TOJ deficit. The final section of the talk will explore the developmental trajectory for interactions between different primary modalities: vision, touch, and audition. Overall, the goal of the talk is to introduce the concept of multisensory integration and give the audience a sample of research questions ongoing in our lab.


Light refreshments before the seminar

Reactive Intermediates & Group Transfer Reactions. We design and synthesize molecular precursors that can be activated by a stimulus to release a small molecule of interest. The molecular precursors themselves are isolated as crystalline solids; they are typically soluble in common organic solvents and can be weighed out and used as needed. For example, the molecule P2A2 (A = anthracene or C14H10) is a molecular precursor to the diatomic molecule P2. Compounds having the formula RPA serve to transfer the phosphinidene (PR) group either as a freely diffusing species (R = NR’2, singlet phosphinidene) or else by inner sphere mechanisms (R = alkyl, triplet phosphinidene). Using the RPA reagents we are developing reactions analogous to cyclopropanation and aziridination for delivery of the PR group to olefins with the formation of three-membered P-containing rings, phosphiranes.

Metaphosphates and Phosphorylating Methodology. Crystalline metaphosphate salts with lipophilic counter cations are useful starting materials applicable in polar organic media. “Metaphosphate” refers to the inorganic ion PO3(-) which, unlike its chemical cousin, nitrate, exists not as a monomeric species but rather as oligomeric rings: [(PO3)n]n-. These cyclic phosphates can be converted into electrophilic phosphorylating agents (a) by treatment with peptide coupling reagents, or (b) by conversion into their crystalline acid forms and subsequent dehydration. Such activated cyclic phosphates can be used directly for oligophosphorylation of C, N, and O nucleophiles. Phosphorylation of the Wittig reagent leads to a new phosphorus ylide with a cyclic phosphate as the C-substituent and a non-hydrolyzable P-C bond, allowing for conjugation of oligophosphate groups to a biomolecule of interest by aldehyde olefination.

Sustainable Phosphorus Chemistry. The industrial “thermal process” by which the raw material phosphate rock is upgraded to white phosphorus is energy intensive and generates CO2. We seek alternative chemical routes to value-added P-chemicals from phosphate starting materials obtained either by the agricultural “wet process” or by phosphorus recovery and recycling from waste streams. Trichlorosilane is a high production volume chemical for its use in the manufacture of silicon for solar panels. We show that trichlorosilane is a reductant for phosphate raw materials leading to the bis(trichlorosilyl) phosphide anion [P(SiCl3)2]- as a versatile intermediate en route to compounds containing P-C bonds.