Researchers at the Francis Creek Institute have developed imaging techniques to capture information about the structure and function of brain tissue at the subcellular level - a few billionths of a meter, while also capturing information about the environment.
The unique approach is described in detail in Nature Communications today (May 25), it overcomes the challenges of imaging tissues at different scales, allowing scientists to see surrounding cells and how they function, so they can build a complete picture of neural networks in the brain.
Different imaging methods are used to gather information about tissue, cells and subcellular structures. However, one method can only capture information about the structure or function of tissues, and a detailed look at the nanometer scale means that scientists are losing information about the wider environment. This means that it is necessary to combine imaging techniques in order to gain a general understanding of tissues.
In their study, the scientists developed an approach that combines seven imaging methods, including in vivo Imaging, synchrotron X-ray and volume electron microscopy. They demonstrated their approach by showing two different areas of the brain in mice - the olfactory bulb and the hippocampus.
It is important that the technique can be applied to other areas of the brain or parts of the body, providing scientists with a more detailed understanding of many different biological structures and tissues.
Each step of the recording process provides different information. First, the researchers used live calcium imaging to visualize neurons in specific regions of the brain and see which neurons were active when mice were exposed to odors.
After the mice were euthanized, brain tissue samples were taken by various methods, including synchrotron X-ray tomography, which captures samples up to several millimeters long. This scale is sufficient for scientists to see entire neural networks and also where certain cells or other structures are located in the broader context of the sample. It is important that this method does not damage the sample so that it can be re-recorded with another technique.
The researchers then selected areas of special interest to be imaged with an electron microscope, recording complex details in high resolution. In some target areas, this could map details of as much as 10 nanometers, allowing researchers to see tiny structures such as individual synapses that connect neurons.
Using computer algorithms, they combined the results to make a complete map of the structure and function of the parts of the brain they studied, down to a few cubic millimeters.
Carles Bosch, first author and lead scientist in laboratory research at the Laboratory for Sensory Circuits and Neurotechnology in Crick, says: “Our approach provides a reliable way to overcome the challenge of imaging structures at very different scales. We believe it will be a powerful tool for investigating neural circuits in the mammalian brain, as well as the structure and function of other tissues. “
Andreas Schaefer, senior author and head of the Laboratory for Sensory Circuits and Neurotechnology in Crick, says: “We are interested in applying this approach to the brain, where it is important to gather information about entire neural networks a few millimeters long next to them. information on specific neurons and synapses.
“But it also has great potential to be useful in other settings, such as cancer biology, where researchers aim to understand the activity of certain cells in the context of a wider tumor.”
The researchers teamed up with the electron microscopy team at Crick, and also worked with synchrotron X-ray teams at Diamond Light Source in Oxfordshire, the European Synchrotron in France and the Paul Scherrer Institute in Switzerland.
The team will continue this research, using this approach to painting to reveal more details about the scented light bulb, as well as to work on further improving the technique.