MS06 - NEUR-1
Senate Chamber (#2145) in The Ohio Union

Uncovering activity patterns, oscillations and other key dynamics of neuronal (and other) networks

Thursday, July 20 at 10:30am

SMB2023 SMB2023 Follow Thursday during the "MS06" time block.
Room assignment: Senate Chamber (#2145) in The Ohio Union.
Note: this minisymposia has multiple sessions. The other session is MS07-NEUR-1 (click here).

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Cheng Ly, Janet Best, Pamela Pyzza, Yangyang Wang


The complexities of neural and other cellular networks currently cannot be elucidated by experiments alone. The detailed circuit electrophysiology at the cellular level, and at large-scale networks require contemporary mathematics and computation to uncover deep insights for how they function. This two-part mini-symposium brings together a broad group of researchers who will discuss their modeling approaches to understand neuro-based phenomena both theoretically and applied to various systems (sleep, sensory, reproductive, gut microbiome, etc.) driven by experimental data in healthy and/or pathological conditions. The researchers will focus on topics that range from analyzing circuit mechanisms of neuron spike dynamics and variability, network connectivity, neural oscillations and other spatiotemporal patterns of activity.

Krasimira Tsaneva-Atanasova

University of Exeter (Mathematics and Statistics)
"Mathematical modelling of GnRH pulse generator frequency modulation through the interaction between kisspeptin and GABA-glutamate in the posterodorsal medial amygdala"
Gonadotrophin releasing hormone (GnRH) pulsatile activity and the initiation of functional gonadotrophin secretion controlling reproductive competence are primarily driven by kisspeptin neurons located in the arcuate nucleus of the hypothalamus. Nevertheless, kisspeptin present in other brain regions, exerts a significant modulating effect on the hypothalamic kisspeptin population. In particular, a population of kisspeptin and its receptors has been found in the posterodorsal medial amygdala (MePD), where it acts as an upstream regulator of γ-aminobutyric acid (GABA) and glutamate sub-populations of neurons. We propose a coarse-grained network model that captures the cooperative and competitive dynamics between these sub-populations. We employ bifurcation analysis to study the effect of network connectivity strengths and the role of the afferent input from kisspeptin. This allows us to characterise the dynamical changes in the MePD output for different levels of kisspeptin. Our mathematical model, supported by experimental findings demonstrate that the effective modulation of the GnRH pulse generator by amygdala kisspeptin neurons is dependent on the functional neurotransmission of both GABA and glutamate.
Additional authors: Kate Nechyporenko, University of Exeter Margaritis Voliotis, University of Exeter Jamie Walker, University of Exeter

Andrea K. Barreiro

Southern Methodist University (Mathematics)
"Fluid dynamics as a driver of retronasal olfaction"
Flavor perception is a fundamental governing factor of feeding behaviors and associated diseases such as obesity. Smells that enter the nose retronasally, i.e. from the back of the nasal cavity, play an essential role in flavor perception. Previous studies have demonstrated that orthonasal olfaction (nasally inhaled smells) and retronasal olfaction involve distinctly different brain activation, even for identical odors. Differences are evident at the glomerular layer in the olfactory bulb (Gautam et al. 2012, Sanganahalli et al. 2020) and can even be identified in the synaptic inputs to the bulb (Furudono et al. 2013). Why does the bulb receive different input based on the direction of the air flow? We hypothesize that this difference originates from fluid mechanical forces at the periphery: olfactory receptor neurons respond to mechanical, as well as chemical stimuli (Grosmaitre et al, 2007, Iwata et al, 2017). To investigate this, we use computational fluid dynamics to simulate and analyze shear stress patterns during natural inhalation and sniffing. We will show preliminary results demonstrating that shear stress forces differ for orthonasal vs. retronasal air flow; i.e. inspiration vs. exhalation, in a model of the nasal cavity, and connect these findings to our earlier work on directional selectivity in neural network models of the olfactory bulb (Craft et al. 2021).

Madeline Edwards

University of Pittsburgh (Department of Neuroscience)
"Exploring the Roles of Interneuron Subtypes in Network Dynamics"
Neuronal responses to sensory stimuli can be strongly modulated by animal's brain state. Three distinct subtypes of inhibitory interneurons, parvalbumin (PV), somatostatin (SOM), and vasoactive intestinal peptide (VIP) expressing cells, have been identified as key players of flexibly modulating network activity. The three interneuron populations have specialized local microcircuit motifs and are targeted differentially by top-down inputs from higher-order cortical areas and neuromodulators. Optogenetic stimulation of different interneuron cell types demonstrates different impacts on neuronal population responses, such as firing rate and network synchrony. In this work, we systematically study the function of each interneuron cell type at controlling network dynamics in a spatially ordered spiking neuron network. We model top down and neuromodulatory inputs as static current applied to each neuron population. We find that the network transitions through three distinct network states, from subcircuit to weak synchrony to strong synchrony state, as we activate the excitatory or SOM population or inactivate the PV or VIP population. Further, we investigate how network responses to modulatory inputs depend on the connectivity of the SOM cells. This work provides a foundational understanding for the modulation of network activity with respect to four unique populations and testable predictions for future experiments.

Andrea Welsh

University of Pittsburgh (Department of Mathematics)
"Modeling Mouse Colon Non-propulsion Dynamics"
Colon motility, the spontaneous self-generated movement and motion of the colon muscle and its cells, is produced by activity in different types of cells such as myenteric neurons of the enteric nervous system (ENS), neurons of the autonomic nervous system (ANS) and interstitial cells of Cajal (ICC). Two colon motor patterns measured experimentally are motor complexes (MC) often associated with the propulsion of fecal contents, and ripple contractions which are involved in mixing and absorption. It has been observed that the MCs can occur without fecal matter present, but it is poorly understood how these spontaneous CMs occur. How ICC and neurons of the ENS and ANS interact to initiate and influence colon motility is still not completely understood. This makes it difficult to develop new therapies to restore function in pathological conditions. This talk will discuss the data-driven modeling of the ICCs and neurons that also capture the spontaneous global dynamics that are observed in the colon and give insight into how these dynamical features may occur.
Additional authors: Kristen Smith-Edwards, Mayo Clinic; Bard Ermentrout, University of Pittsburgh

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Annual Meeting for the Society for Mathematical Biology, 2023.