To understand computation in the brain, one needs to understand the input-output relationships for neural circuits and the anatomical and functional properties of individual neurons therein. Optical microscopy has emerged as an ideal tool in this quest, as it is capable of recording the activity of…

The urgency to probe biological dynamics is impeded by a major challenge: the large dynamic range of biological processes—interactions of molecules within milliseconds can lead to changes across the whole-organism over days to years. It calls for measurements with both high spatiotemporal resolution and large-scale long-term coverage. However,…

Animal genomes are folded into loops and topologically associating domains (TADs) by CTCF and loop extruding cohesins. These loops and domains are thought to play critical roles in regulating gene expression by regulating long-range enhancer-promoter interactions. But whether CTCF/cohesin loops are stable or dynamic structures was…

In the event of metastatic disease, emergence of a lesion can occur at varying intervals from diagnosis and in some cases following successful treatment of the primary tumor.  Genetic factors that drive metastatic progression have been identified, such as those involved in cell adhesion, signaling, extravasation and metabolism. However,…

We are interested in how physics at the colloidal scale instantiate life in biological cells. While principles from physics have driven recent paradigm shifts in how collective biomolecular behaviors orchestrate life, many mechanistic aspects of e.g. transcription, translation, and condensation remain mysterious because…

My lab studies the brains of larval fruit flies as models of neural computation. We are interested in the rules by which the larval brain transforms sensory input into motor output to navigate an uncertain environment, how the larva’s brain changes these rules as it learns new information, and how these rules and changes are encoded in the…

Measurement of natural systems typically involves perturbation and interpretation. In this talk, I will discuss the implications of measurement in the context of RNA in gene expression in human cells. I will focus on measurements of RNA biology using high-throughput sequencing, which are powerful for their scale but also involve perturbations…

How does learning occur? Neural networks learn via optimization, where a loss function is minimized by a computer to achieve the desired result. But physical networks such as mechanical spring networks or flow networks have no central processor so they cannot minimize such a loss function. An alternative is to encode local rules into those…

The new field of stochastic thermodynamics allows us to analyze the thermodynamic behavior of dynamic systems arbitrarily far from thermal equilibrium, and has produced many powerful theorems concerning phenomena completely absent in traditional statistical physics. However, to date stochastic thermodynamics has (mostly) been applied to systems…

Mechanical stability and shape changes of cells are determined by the dynamic interplay of four distinct cytoskeletal networks, made of actin filaments, microtubules, intermediate filaments and septins. These four filamentous systems contribute different structural and dynamical properties, enabling specific cellular…

Liquid-liquid phase separation of cell membranes exemplifies a biological system leveraging a physical concept to achieve a chemical end. Here, we show that yeast actively tune the transition temperature of their vacuole membranes to be close to the yeast's growth temperature, which implies that the membrane's proximity to the miscibility…

Understanding the physics of living systems allows us to design new materials that are active and adaptive, akin to cells and tissues. Conversely, these active matter systems can reveal fundamental principles in physics and biology. In this talk, I will discuss three systems that feature this synergy, ranging from the molecular to the…

To understand computation in the brain, one needs to understand the input-output relationships for neural circuits and the anatomical and functional properties of individual neurons therein. Optical microscopy has emerged as an ideal tool in this quest, as it is capable of recording the activity of neurons distributed over millimeter dimensions…

After a century of biochemical and genetic onslaught on the embryo we are left with an inexhaustive parts list with an increasingly baroque logic. How do we begin to assemble complex living systems from knowledge of the parts list? In this talk I will attempt to pursue a statistical (physics) approach to discerning the design principles that…

Controlling interfacial structure and dynamics of phase separating fluid mixtures is key to creating diverse functional materials. Traditionally, this is accomplished by controlling interface chemistry, through the presence of surface-modifying amphiphilic agents. Using a phase separating mixture of active and passive fluids, we study how…