Brain Cells Record Their Activity in Gene Expression, New Study Finds
Source: Harvard Medical School
Summary: Researchers reported that bits of a neuron’s activity record can be reconstructed by analyzing its gene expression pattern the particular genes that are active in the cell.
From burning your palm on a hot pan handle to memorizing the name of a new acquaintance, anytime you experience something, your neurons are active. Different experiences stimulate different patterns of activity in brain cells. Researchers want to track these activity patterns to better understand how the brain makes sense of the world, but they’ve been limited by the transient nature of the activity and by the tiny fraction of neurons they’re able to study at once only a few thousand out of an estimated 100 billion. Researchers from the Harvard Medical School reported that bits of a neuron’s activity record can be reconstructed by analyzing its gene expression pattern the particular genes that are active in the cell. Specifically, the researchers found that expression patterns reflect how long a neuron fired in response to a stimulus. The study findings were published in the journal Neuron.
The scientists used an established experimental method in which mice are housed in the dark for a while to clear out any residual gene expression related to light exposure; then they turned on lights near the cages for either a few minutes or a longer time. The team recorded the activity of light-sensing neurons in the mice’s visual cortex, a brain region that handles vision. Given this consistent outcome, the researchers wondered: Would it be possible to estimate the duration of an earlier exposure simply by looking at a neuron’s gene expression? The answer, it seemed, was yes. A graduate student Tyssowski successfully trained a computer to look at gene expression patterns in neurons from the mouse experiment and guess whether they had undergone brief or sustained light exposure.
Asst. Prof. Jesse Grey said, “The longer a neuron’s activity persists, the more genes are turned on by it”, “Because gene expression is easier to measure across many neurons than neuronal activity, linking the two should now allow researchers to “analyze the activity patterns of tens of thousands of neurons in a single experiment.”
More Information: Kelsey M. Tyssowski et al, “Different Neuronal Activity Patterns Induce Different Gene Expression Programs”, Neuron (2018). DOI: 10.1016/j.neuron.2018.04.001