To ensure all of our metabolic functions, transmit a sense or cause a mechanical response, our nervous system must continuously process a large amount of information. They take the form of neural impulses and pass through our neurons at very high speed. The speed is such that the event can never be seen directly. Using recent advances in high-speed photography, the engineers of the California Institute of Technology have developed an ultra-rapid camera capable of capturing the movement of electrical impulses through neurons. Observation of this previously elusive phenomenon can lead to a better understanding of brain biology, which is fundamental in the search for neurological treatments. Electromagnetic signals moving at the speed of light can also be captured.
To get a sense through our peripheral nervous system, a whole cascade of information is transmitted to the central nervous system. The nerve pulse passes through the neurons of the spinal cord and reaches the talamus cells.
These complex interactions involving many neurological functions are taking place extremely quickly. Nervous impulses on sensory nerves are moving at a speed of almost 160 kilometres per hour. Feelings requiring immediate reaction can generate even faster nerve impulses at a speed of 483 kilometres per hour.
Medical visualization technologies, such as a functional MRI, can show which areas of the brain are activated by nerve impulses, but "," says Lihong Wang, a co-author of a new study described in the journal, and a researcher at the Kaltech Visual Visualization Laboratory.
For the first time, the movement of these nerve impulses on the axons could be recorded using a camera using the Differential Enhanced Compressed Ultrafast Photography technology and recording video at 70 billion frames per second. Diff-CUP combines this system with a device called Maha-Cender Interferometer to record sensory nerve pulses.
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Using the Maha-Cender interferometer, the new Diff-CUP camera can film moving objects by dividing the light beam into two. Then only one of the two fragments passes through the object and recombinates from the first one at the exit. Since light waves are influenced by the objects they pass through, the beam passing through the object is disinclined with a beam that does not pass through it. This desynchronization causes interference whose patharies reveal the object's information.
This type of interferometry has also been used to detect gravitational waves, and its connection to CUP allows images to be obtained at incredibly high speeds. To test their technology, researchers have removed electrical impulses passing through frog sedation nerves.