@article {70148, title = {Emergence of Functional Heart-Brain Circuits in a Vertebrate.}, journal = {eLife}, year = {2025}, month = {2025 Dec 22}, abstract = {

The early formation of sensorimotor circuits is essential for survival. While the development and function of exteroceptive circuits and their associated motor pathways are well characterized, far less is known about the circuits that convey viscerosensory inputs to the brain and transmit visceromotor commands from the central nervous system to internal organs. Technical limitations, such as the\ in utero\ development of viscerosensory and visceromotor circuits and the invasiveness of procedures required to access them, have hindered studies of their functional development in mammals. Using larval zebrafish{\textemdash}which are genetically accessible and optically transparent{\textemdash}we tracked,\ in vivo, how cardiosensory and cardiomotor neural circuits assemble and begin to function. We uncovered a staged program. First, a minimal efferent circuit suffices for heart-rate control: direct brain-to-heart vagal motor innervation is required, intracardiac neurons are not, and heart rate is governed exclusively by the motor vagus nerve. Within the hindbrain, we functionally localize a vagal premotor population that drives this early efferent control. Second, sympathetic innervation arrives and enhances the dynamics and amplitude of cardiac responses, as neurons in the most anterior sympathetic ganglia acquire the ability to drive cardiac acceleration. These neurons exhibit proportional, integral, and derivative{\textendash}like relationships to heart rate, consistent with controller motifs that shape gain and dynamics. Third, vagal sensory neurons innervate the heart. Distinct subsets increase activity when heart rate falls or rises, and across spontaneous fluctuations, responses to aversive stimuli, and optogenetically evoked cardiac perturbations, their dynamics are captured by a single canonical temporal kernel with neuron-specific phase offsets, supporting a population code for heart rate. This temporally segregated maturation isolates three experimentally tractable regimes{\textemdash}unidirectional brain-to-heart communication, dual efferent control, and closed-loop control after sensory feedback engages{\textemdash}providing a framework for mechanistic dissection of organism-wide heart{\textendash}brain circuits.

}, issn = {2692-8205}, doi = {10.1101/2025.09.22.677693}, url = {https://doi.org/10.7554/eLife.109362.1}, author = {Hernandez-Nunez, L and Avrami, J and Shi, S and Markarian, A and Ruetten, Virginia M.S. and Boulanger-Weill, J and Zarghani-Shiraz, A and Ahrens, M and Engert, F and Fishman, M C} } @article {5676, title = {Multilinear models of single cell responses in the medial nucleus of the trapezoid body.}, journal = {Network}, volume = {21}, year = {2010}, month = {2010}, pages = {91-124}, abstract = {

The representation of acoustic stimuli in the brainstem forms the basis for higher auditory processing. While some characteristics of this representation (e.g. tuning curve) are widely accepted, it remains a challenge to predict the firing rate at high temporal resolution in response to complex stimuli. In this study we explore models for in vivo, single cell responses in the medial nucleus of the trapezoid body (MNTB) under complex sound stimulation. We estimate a family of models, the multilinear models, encompassing the classical spectrotemporal receptive field and allowing arbitrary input-nonlinearities and certain multiplicative interactions between sound energy and its short-term auditory context. We compare these to models of more traditional type, and also evaluate their performance under various stimulus representations. Using the context model, 75\% of the explainable variance could be predicted based on a cochlear-like, gamma-tone stimulus representation. The presence of multiplicative contextual interactions strongly reduces certain inhibitory/suppressive regions of the linear kernels, suggesting an underlying nonlinear mechanism, e.g. cochlear or synaptic suppression, as the source of the suppression in MNTB neuronal responses. In conclusion, the context model provides a rich and still interpretable extension over many previous phenomenological models for modeling responses in the auditory brainstem at submillisecond resolution.

}, keywords = {Action Potentials, Animals, Auditory Pathways, Computer Simulation, Gerbillinae, Linear Models, Models, Neural Inhibition, Neurological, Neurons, Olivary Nucleus, Predictive Value of Tests, Sound Localization, Synaptic Transmission}, issn = {1361-6536}, doi = {10.3109/09548981003801996}, author = {Englitz, B and Ahrens, M and Tolnai, S and R{\"u}bsamen, R and Sahani, M and Jost, J} }