Surprising: neurons in the visual cortex of the brain "drift" over time

Although other studies have demonstrated the "representation drift" of neurons in the brain related to smell and spatial memory, this result is surprising because neural activity in the primary visual cortex is considered relatively stable
.

The research was published in the August 27 issue of Nature Communications and was led by Ji Xia, a PhD student in the laboratory of Ralf Wessel, a professor of physics in the arts and sciences
.
Xia is now a postdoctoral fellow at Columbia University

"We know that the brain is a flexible structure because we expect that when we learn or gain experience, the neural activity in the brain will change over time-even in adults," Xia said
.
"Somewhat unexpectedly, even if there is no learning or experience changes, the neural activity in different areas of the brain will still change over time

Researchers in Wessel's group explored the processing of sensory information in the brain

Michael J.
Goard, co-senior author from the Neuroscience Research Institute at the University of California, Santa Barbara, plays a single short film loop to the mouse
.
(They borrowed the opening part of Orson Welles' classic black-and-white film, which is a necessary condition for mouse vision research today

Scientists watch the same 30-second movie clip repeatedly every week for up to 7 weeks, recording the activity of the same neurons in the same mouse
.

Then, physicists at the University of Washington analyzed the data of the mice watching the movie and used a new calculation method to analyze the changes in the number of neurons over time
.

The researchers found that the response of a single neuron to natural movies was unstable for several weeks
.
In other words, when the mouse watched a movie in one week and another week in the movie, the response of a single neuron to the visual stimulus was different—what happened on the screen at the same time

However, in this study, University of Washington physicists were able to develop a way to decode trans-weekly responses to visual stimuli.
If they consider all neurons of the population activity to track a given mouse, they just can't use a single neuron alone
.

Although Xia used population activity to draw a consistent representation of a movie clip, scientists still don't know whether the representation of the primary visual cortex is actually read by the lower brain area
.

In the past 10 years, neuroscientists have increasingly recorded similar examples, showing that there is a "representative drift" in neural activity in different areas of the brain-the first studies reported on neuronal activity in the hippocampus and posterior parietal cortex Drift
.

But even if these studies have been published, many scientists are not ready to deal with the possibility of drift in other areas of the brain, Xia said
.

"People still don't think this drift comes from the primary visual cortex," she said
.
"It is generally agreed that these primary sensory cortex should be very reliable because they should faithfully encode information from sensory stimuli

Journal Reference :

1. Ji Xia, Tyler D.

   
   Marks, Michael J.