The researchers used high-speed light sheet microscopy to image the activity of 80% of the neurons in the brain (which is composed of ~100,000 neurons) of a fish larva at 0.8 Hz (an image every 1.3 seconds), with single-cell resolution.
This represents the first technology that achieves whole brain imaging of a vertebrate brain at cellular resolution with speeds that approximate neural activity patterns and behavior, as Nature Methods methagora blog noted.
The authors saw correlated activity patterns at the cellular level that spanned large areas of the brain — pointing to the existence of broadly distributed functional circuits.
The next steps will be to determine the causal role that these circuits play in behavior — something that will require improvements in the methods for 3D optogenetics, the blog said. Obtaining the detailed anatomical map of these circuits will also be key to understand the brain’s organization at its deepest level.