Characterizing Developmental Myelination and Auditory Processing in Zebrafish Larvae — The Association Specialists
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Characterizing Developmental Myelination and Auditory Processing in Zebrafish Larvae (21590)

Marcello Lepre 1 , Rebecca Lee 2 , Cheryl Lee 1 , Raphael Ricci 1 , Rob Gasperini 3 , Ethan K Scott 2 4 , Kaylene M Young 5 , Itia Favre-Bulle 2 , Carlie L Cullen 1 5
  1. Mater Research Institute, University of Queensland, Brisbane, Woolongabba, Queensland, Australia
  2. Queensland Brain Institute, University of Queensland , Brisbane, St. Lucia, 4067, Australia
  3. School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
  4. University of Melbourne, Parkville, Victoria, Australia
  5. Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia

Altered brain myelin content has been linked to neurodevelopmental disorders characterized by changes in network connectivity and information processing. Developmental myelination may be a key regulator of neural circuit formation and function. Our research aims to determine how altered myelin development affects sensory information processing.

To characterise the temporal pattern of myelination within the developing zebrafish central nervous system, we imaged fluorescently labelled myelin in live, intact tg(MBP:mScarlet) larvae from 3-12 days post fertilisation (dpf). Using IMARIS software to 3D reconstruct and quantify myelin we revealed a rostro-caudal pattern of myelination. Myelin was first present the spinal cord and hindbrain at 3dpf and continued to increase in volume until 12dpf. In the midbrain, myelination began at 5dpf, increased between 5-7dpf but remained consistent between 7-12dpf. No myelin was observed in the forebrain.

To determine the importance of appropriate myelination in neural network function we generated a model of delayed myelination by selectively ablating newly formed oligodendrocytes between 3-5dpf in tg(MBP:NTR:mCherry) larvae. We performed whole brain calcium imaging to record brain-wide neuronal activity in tg(MBP:NTR:mCherry); tg(HuC:H2B-GCaMP7c) or tg(MBP:mCherry); tg(HuC:H2B-GCaMP7c) double transgenic larvae at 6dpf . So far, we show that in control tg(HuC:H2B-GCaMP7c) larvae, neurons within the torus semicircularis, medial hindbrain and thalamus exhibit periodic bursting activity that corresponds to auditory stimulus presentation (30ms, 1kHz tone delivered every 30s). 

Consistent with current literature, our early data, demonstrate a rostro-caudal pattern of myelin development and that the torus semicircularis, medial hindbrain and thalamus are key regions involved in auditory processing.