UCLA researchers decode muscle mechanics behind the indicators

A wink seems natural and instantaneous, but is it? Similarly, Without a functional eyelid, the eye can become dry, irritated and finally lose the ability to see clearly.

Now. Moreover, a team of biomechanical engineers and UCLA ophthalmologists has discovered new details on the muscle that controls flashes, offering a path to the development of prostheses assisted by flashes. In addition, Published in the Proceedings of the National Academy of SciencesThe study revealed that the occupied orbicularis – the muscle which controls the movement of the eyelids – contracts in complex patterns which vary according to the action. Therefore, move the eyelid in more than a simple movement from top to bottom.

The researchers studied how this muscle behaves differently in various actions, including spontaneous flashes, rapid protective closures and closed movements.

ucla researchers decode muscle mechanics

“The movement of the eyelid is both more complex. Moreover, more precisely controlled by the nervous system than expected,” said the author corresponding to the Tyler Clites study, assistant professor of mechanical engineering and aerospace at the UCLA Samueli School of Engineering. Nevertheless, “Different parts of the muscle activate in carefully timed sequences depending on what the eye does. Similarly, This level of muscle control has never been recorded in the human eyelid. Similarly, Now that we have this information in detail. However, we can move forward in the design of neuroprostheses which help to restore the function of natural eyelids. »»

In experiences with volunteers. the researchers examined five different ways of the eyes:

• Spontaneous blink: an automatic and unconscious flashing that occurs regularly to keep the eye lubricated
• Blink Volunteer: An intentional flashing, as when someone is invited to blink on the order
• Reflexive blink: a quick ucla researchers decode muscle mechanics and involuntary flashing has triggered to protect the eye from a collision
• Sweet closure: a soft and slow descent of the eyelids, similar to the start of sleep
• A forced closure: a deliberate compression of the eyelids firmly closed

To record the activity among the Oculi orbicicula with high precision, an ophthalmic surgeon inserted tiny wire electrodes in the eyelid. The researchers then used a motion capture system to follow the movement of the eyelids in the ultraslow movement. These tools allowed the team to measure subtle differences in the movement of the eyelids. in particular speed, management, and what part of the muscle initiated the action.

“People can lose the ability to blink due to a stroke, a tumor, an infection or an injury. The condition is painful in the short term. can damage the eyes enough to cause vision loss, “said the study co-author, Dr. Daniel Rootman. ucla researchers decode muscle mechanics an associate professor of ophthalmology at David Geffen School of Medicine at the UCLA and director of the Center of UCLA Orbital Disease. “We know that a small electric pulse can stimulate the Oculi orbicularis muscle to move. but design one that works well has been elusive. What we have now is a good roadmap for such a device. including where exactly the electrodes, how to time them, and the pulse strength.

With this fundamental knowledge of eyelid in hand. researchers can now work to refine a prototype neuroprosthesis to help people flash.

“Understanding the functioning of the eyelids is crucial to design a specific stimulation model for a prosthesis. as well as for diagnostic purposes,” said the first author of the study, Jinyoung Kim, a doctoral student in Mechanical Engineering of the UCLA and a member of the Clits of Clits, the Anatomical Engineering Group at UCLA. “We are ucla researchers decode muscle mechanics more than delighted to fill this gap. go ahead to work with patients who have facial paralysis and help improve their lives. »»

Other authors. all of the UCLA, include Ashley Shirriff, Jordan Cornwell and Maria Paula Quintero Mutis with ophthalmic plastic and reconstructive surgery; And Ereni Delis and Sophia Wang, both undergraduate researchers from the Clies group. Clies also has joint appointments from teachers in the Bio-Engineering departments at UCLA Samueli. orthopedic surgery at the Geffen School of Medicine.

Research was funded by the National Institute National Institute of the National Institutes of Health.