Imaging reveals patterns in neuron firing
In the brain, cortical neurons fire in response to stimuli from the body, and thalamic neurons provide feedback that regulates the cortical neurons' firing―and thus helps keep the brain functioning smoothly. To find out more about the interplay between these two types of neurons, researchers in the Brain Mechanisms for Behavior Unit grew them in a dish from embryonic neurons. Since changes in calcium concentration indicate a neuron has fired, they stained the neurons with a dye that becomes brighter when calcium is present. The bright dots are neurons, which give off bursts of light when they fire. In this video, the researchers can see how the cortical neurons (at the top if the image) often fire along with the thalamic neurons at the bottom of the image. This pattern of firing is like that predicted to happen when we sleep. The clip has been sped up to about 3x the actual speed of events. The individual neurons (bright dots) are about 0.01 mm across.