Neural activity of moving animal recorded in 3D

Researchers in Princeton University have developed an instrument that allows three-dimensional recordings of neural activity in nearly the entire brain of a free-moving animal.

The recordings could provide scientists with a better understanding of how neurons coordinate action and perception in humans.

Much previous work related to neuron activity either focuses on small subregions of the brain or is based on observations of organisms that are unconscious or somehow limited in mobility, explained corresponding author Andrew Leifer, associate research scholar in Princeton's Lewis-Sigler Institute for Integrative Genomics.

"This system is exciting because it provides the most detailed picture yet of brain-wide neural activity with single-neuron resolution in the brain of an animal that is free to move around," Leifer said.

The researchers recorded 3-D footage of neural activity in the nematode Caenorhabditis elegans, a worm species one millimetre long with a nervous system containing a mere 302 neurons.

The researchers correlated the activity of 77 neurons from the animal's nervous system with specific behaviours, such as backward or forward motion and turning.

Neural networks are infinitesimal arrangements of chemical signals and electrical impulses that can include, as in humans, billions of cells.

The simpler nervous system of C. elegans provided the researchers with a more manageable testing ground for their instrument.

Yet, it also could reveal information about how neurons work together that applies to more complex organisms, Leifer said.

For instance, the researchers were surprised by the number of neurons involved in the seemingly simple act of turning around.

"One reason we were successful was that we chose to work with a very simple organism," Leifer said.

"By studying how the brain works in a simple animal like the worm, however, we hope to gain insights into how collections of neurons work that are universal for all brains, even humans," he said.

The findings appeared in the journal Proceedings of the National Academy of Sciences (PNAS).