Zebrafish is an important model system in neuroscience owing to its near-complete transparency during the initial two weeks of its larval stage. This remarkable characteristic enables neuoscientists to monitor the entire brain's activity of these larvae in vivo at a cellular resolution using calcium imaging, a possibility that is unique among vertebrates. However, this very limited imaging time-window hinders our ability to apply these optical techniques to investigate more advanced behaviors, such as social interactions and learning. In recent years, a solution to this limitation has emerged with the introduction of Danionella Cerebrum. Danionella, the smallest known vertebrate, maintains its small and nearly transparent brain structure until reaching adulthood.

The objective of this project is to explore the emergence of learning abilities in Danionella from the larval to the juvenile stage (one to six weeks of age). In order to do so, we will use an experimental platform recently developed in the lab, which enables real-time tracking and high-resolution video monitoring of individual Danionella specimens. Additionally, a video projector allows us to deliver precisely controlled visual stimuli to the animals. Using this setup, we aim to condition the animals to associate specific visual patterns with rewards, represented by changes in light intensity. Our investigation will focus on determining the age at which this learning capacity emerges in Danionella.

Similar experiments will then be ported onto a system in which the animal, partially tethered, interact with a visual environment, which we perform brain imaging. This behavioral study thus represents a first step to study the neural basis of learning in the vertebrate brain.

Expertise to gain during the project:

• Behaviorial recordings
• Image processing
• Light-sheet microscope
• Calcium imaging of neuronal activity
• Data analysis in Python and/or Matlab

Supervisors:

• Volker Bormuth volker.bormuth@upmc.fr
• Georges Debrégeas georges.debregeas@sorbonne-universite.fr

Location: Laboratoire Jean Perrin

Possibility to continue with a PhD: Yes