LIN Seminar: Rui Gao and Joseph Zak
September 2, 2021
4:00 PM - 5:00 PM
UIC's Rui Gao and Joseph Zak will each give a short introduction of their research to the LIN Community.
Rui Gao will present "Architecture and Function of Neural Circuits at the Molecular Scale"
Abstract: Neural circuits and the underlying synaptic architecture span orders of magnitude in spatial scales ranging from nanometers to centimeters. Yet the tradeoffs between resolution, imaging speed, and photodamage constrain the ability of light microscopy to capture their anatomy and function. In this talk, I will discuss our recent work combining tissue expansion and clearing with ultrafast low-photobleaching light-sheet microscopy in an effort to map the ultrastructure of organelles, synapses, myelin sheaths, and neurites across millimeter-sized tissue. Using this new approach, we have studied the ratio of dopaminergic presynaptic sites over the entirety of a fruit fly’s brain, the spatial distribution of pre- and post-synaptic sites in a mouse cortical column, and the stereotype of neuronal projections between multiple brain regions, all at 60-90 nm spatial resolution. Lastly, I will discuss the importance and applications of these findings for neuroanatomy, connectomics, and functional multi-omics
Joseph Zak will present "Nonlinear stimulus coding in the olfactory system"
Abstract: Imagine the aroma of your favorite blend of coffee. The smell is intricate, much more than simply “coffee”. Perhaps you identify subtle olfactory notes of cocoa, nuttiness, and a hint of vanilla. Together, the interactions between these notes transform the experience of your morning cup into something beyond the sum of its parts.
Within your nose, the olfactory notes of coffee each bind to, and activate, specialized sensory neurons that recognize the molecular shape of an odor molecule. However, different odor molecules, may compete for the same receptor neurons, thereby complicating the interpretation of sensory neuron activity by the brain. A central question at the heart of understanding stimulus interactions in the across all sensory systems is how overlapping stimuli are encoded and recognized by their respective sensory cells. This question is especially pertinent in the olfactory system where the number of possible stimuli vastly exceeds the complement of receptor cell types and where relevant stimuli must be detected against complex backgrounds.
We first developed a model which predicted that competition between odor molecules for the same receptors may increase the stimulus coding capacity of the olfactory input layer. We then empirically tested these predictions using a new approach, which allowed us for the first time to directly measure the activity of individual sensory neurons in freely- breathing mice. When we delivered naturalistic odor blends to mice, we observed widespread antagonistic interactions that were predicted by our model. Our analysis demonstrates that these interactions fundamentally reformat how odor blends are encoded by olfactory sensory neurons. Combining theory and experimental data, we provide new evidence that while the aroma of coffee is perceived to exceed the sum of its parts, at the level of peripheral stimulus encoding the neural representation of coffee is in fact less than the sum of its parts.
Date posted
Aug 10, 2021
Date updated
Aug 24, 2021