Functional organization and physiology of the afferent neuronal network in the lateral line system of the larval zebrafish (Danio rerio)
Final Report Abstract
During the project I addressed four questions outlined as aims in the original proposal of the project. The questions all focused around understanding the physiology of the afferent network in the larval zebrafish lateral line system and to relate structure to function. The lateral line system of fishes is a sensory organ system for sensing changes in water flow around the fish body. In larval zebrafish it consists of a few dozen hair cell organs distributed over the surface of the head and trunk. Each of these hair cell organs, called neuromasts, is connected to a small number of afferent neurons which project into the hindbrain. The cell bodies of the afferent neurons are located in two ganglia anterior and posterior of the otic capsule (location of acoustic and equilibrium sense of the fish). The cell bodies in these ganglia are accessible for electrophysiological recordings and anatomical labeling techniques. The free swimming larvae are translucent five days after fertilization which allows imaging of labeled neurons in vivo. Furthermore larval zebrafish exhibit a rich behavioral repertoire; swimming and escape responses mediated by the lateral line can be reliably induced in an experimental set up. The work regarding three of the aims: 1. Characterization of lateral line afferent neurons by stimulating their connected neuromasts with different frequencies in order to identify subpopulations with distinct physiological properties; 2.Characterizing the organization of lateral line afferent innervation during development; and 3. Identification of the somatotopic organization of lateral line afferent neurons onto post-synaptic targets in the hind brain; were completed and the results published in peer reviewed journals. The work for aim four: Imaging of population responses of lateral line afferent neurons to flow stimuli using intracellular calcium indicators, is still ongoing in the hosting lab due encountering some technical difficulties during the data collection. In addition to the originally proposed work we have completed a project on larval behavior mediated by the lateral line and published the results. By quantifying morphological connections in the lateral line system and furthering our understanding of its physiology the work completed during this project provides a foundation to understand how hydrodynamic information is processed and ultimately translated into appropriate motor behaviors.
Publications
- (2012): Heterogeneity and dynamics of lateral line afferent innervation during development in zebrafish (Danio rerio). The Journal of Comparative Neurology 520 (7), 1376-1386
Haehnel M, Taguchi M, Liao JC
- (2012): Zebrafish larvae exhibit rheotaxis and detect and escape a continuous suction source using their lateral line. PLoS ONE 7(5), e36661
Olszewski J, Haehnel M, Taguchi M, Liao J
- (2014) Regional Specialization of Posterior Lateral Line Efferent Neurons in the Hindbrain of Larval Zebrafish. Integrative and Comparative Biology 54, E351-E351
Smith CA, Haehnel-Taguchi M, Liao JC
- (2014) Sensory and Motor Responses to Deflection of Single Neuromasts in the Lateral Line System in Larval Zebrafish. Integrative and Comparative Biology 54, E123-123
Liao JC, Akanyeti O, Ballo A, Haehnel M, Levi R
- (2014): Afferent and motor neuron activity in response to single neuromast stimulation in the posterior lateral line of larval zebrafish. Journal of Neurophysiology 112(6), 1329-1339
Haehnel-Taguchi M, Akanyeti O, Liao J
(See online at https://doi.org/10.1152/jn.00274.2014)
