Cell: new research reveals how neural circuits develop in the embryonic period

September 26, 2019 BIOON / -- the development and maturation of neuron cells need to start from embryo to reach the nervous system However, we are not clear about the detailed process "A lot of the processes we're guessing right now are unobservable," said Yinan Wan, a scientist at the Howard Hughes Institute of medicine Now, Wan and her colleagues have developed tools to directly observe animal activity (image source: Wan et al, cell 2019) according to the team's latest achievements, using new imaging technology, they can track the development of zebrafish neurons in real time The results were published in the recent cel journal This is the first time that scientists have tracked the origin, movement and function of all neurons from beginning to end New perspective Wan and his colleague Philipp Keller and the rest of his team spent about seven years building, collecting and analyzing the tools needed for neuron development "The technology we need to track the development of an entire embryo at a single cell level," Keller said It's not hard to find a microscope that can image a large area, capture tiny details or take real quick pictures But often these functions need to be weighed For the experiment, Keller's team needed a microscope that could do all of this simultaneously on tiny organisms They are based on a grating microscope developed by Keller Last year, the team used similar techniques to see how cells divide, move and form organs during mouse embryo development This time, Keller's team focused on the nervous system, tracking not only the unknown cells, but also what each cell was doing First, scientists bred zebrafish with fluorescent markers In embryonic neurons, they have successfully labeled a molecule that reports neuronal activity and a small number of key proteins that exist only when the cell has a specific function This information allowed the team to distinguish between different types of neurons and see if they played a role Keller's team then watched the zebrafish embryo for 14 hours, capturing the movement of all cells at the rate of four 3-D images per second and tracking the activity of cells, resulting in millions of high-resolution snapshots Wan and others developed algorithms in the lab that helped them reconstruct the pathways of individual neurons Collaborators zizixiang Wei and Shaul druckmann developed computational techniques for analyzing patterns of neuronal activity Over time, microscopic images show how cells move and find their corresponding positions The results showed that, at the single cell level, how the highly coordinated network activities first appeared and caused the early behavior of zebrafish individuals "A lot of computational neuroscience now revolves around how to understand the patterns of neuronal population activity," said druckmann of Stanford University Development studies like this add a whole new dimension: it is meaningful not only for the current characteristics of group activities, but also for the development and change of these patterns over time " Wan said the neural circuit they focused on (the one in the spinal cord of zebrafish) was one of the first to develop in fish It has been widely studied from different perspectives by many researches before However, little is known about how each nerve unit in the neural circuit matures and starts to work together The motor circuit has not only the motor neurons that talk with muscles, but also the neurons that transmit signals from other neurons Sometimes it also acts as a pacemaker The team found that as developing fish circuits formed, motor neurons were the first cells to send information "In the past, we have reconstructed the development of a single organ or even an entire embryo, but we have never combined it with the whole system high-speed functional imaging of the same cell," Keller said By studying the development and function of brain cells simultaneously, researchers can draw the realization process of neural function at the single cell level Information source: how natural circuits form in a developing embryo original source: Yinan Wan, Ziqiang Wei, Loren L logger, Minoru Koyama, Shaul druckmann, and Philip J Keller "Single cell reconstruction of emerging population activity in an overall developing circuit." cell Published online segment 26, 2019 Doi: 10.1016/j.cell.2019.08.039