Spontaneous activity in the zebrafish larval tectae.

THOMAS PIETRI; SEBASTIAN A. ROMANO; VERONICA PEREZ SCHUSTER; GERMAN SUMBRE

San Diego

Congreso; SfN's 43nd annual meeting; 2013

SFN

In absence of sensory stimulation, sensory brain areas remain very active. For a long time, this activity was merely considered as electrical noise. Lately, however, it has been shown that this spontaneous activity posses a patterned structures, that may profoundly influence many developmental processes including, for instance, cell migration and differentiation, network formation and connectivity. We use here the visual system of zebrafish larvae to study the development of the spontaneous activity in the tectum and relate this activity to visually induced activity. Multiphoton calcium imaging of transgenic fish expressing the calcium probe GCaMP3 under the control of the pan-neuronal promoter HuC allows for the monitoring of a large fraction of the tectal cells over long periods. We found that spontaneous activity is present in the earlier stage of visual system development and becomes structured when a functional connection between retina and tectum is achieved. Moreover, we reveal the patterned activity of spontaneous activity by extraction of groups of synchronous cells. We present here the result of this neuronal clustering and the modulation of its structure in the course of early visual system development. This structure appears to relate closely to the patterns of visually induced synchronous group of neurons, raising the possibility of a role of the spontaneous activity in the refinement of visually induced tectal activity.