A Circuit Neuroscience Seminar (CNS)

The discoveries of the coding principles of vision, somatosensation, olfaction, gustation, and audition are all landmark achievements. However, little is known about how the brain encodes information from the visceral organs to generate our internal senses, including satiety, thirst, hypoxia, nausea, and visceral pain.

My study developed a novel in vivo two-photon mouse brainstem calcium imaging system, which allows us, for the first time, to study the representations of internal organs in the nucleus of the solitary tract (NTS), the viscerosensory gateway of the brain. I discovered that (1) the NTS uses a combinatorial code to represent diverse mechanical and chemical stimuli within the same organ. (2) By contrast, different organs are represented by discrete neuronal ensembles that function as dedicated “labelled lines”, each comprised of heterogeneous cell types. (3) Organs are topographically mapped in the brainstem, forming a “visceral homunculus” (Fig. 1). (4) Spatial organization of different organs is further sharpened by inhibition, as blockade of NTS inhibition broadens neural tuning and blurs visceral representations. These studies reveal basic coding principles used by the brain to process visceral inputs (Ran et al., Nature, 2022). Our study provides the first analysis of the logic used by the brain to process interoceptive inputs. In addition, our study helps define the wide-open field of viscerosensory coding, laying the foundation for future work to comprehend the neural processing of bodily signals throughout the brain.

Join via Zoom: https://bristol-ac-uk.zoom.us/j/92805884735