Mind-controlled prosthetic limbs have been a reality for a few years, but researchers have not found ways to give the people who use them the same, smooth motor control that people have over their natural limbs.
Now, a team of researchers says the members have solved part of the problem of smooth motor control by connecting an artificial limb to a different part of the brain. Previous designs for mind-controlled prostheses linked the artificial limb to either the person’s motor cortex or the individual’s premotor cortex, which both translate signals from the brain to the limbs.
This time, the connections to the robotic arm were wired into a patient’s posterior parietal cortex, which is located on the side of the head near the ear.
“The [posterior parietal cortex] forms the initial plans to make movements,” said Richard Andersen, a professor of neuroscience at the California Institute of Technology and one of the researchers who developed the new prosthesis. For example, when a person decides to grab a coffee cup, the posterior parietal cortex outlines the steps in movement, then, the motor cortexes translate that plan into actual signals that are sent to specific parts of the arm.
The researchers used signals from the posterior parietal cortex “to extract the intent of the subject,” Andersen told Live Science. “Instead of ‘I want to control muscles,’ we can use smart robotics to work out the fine details” of the movement a person wants to make.
In a report published in the May 22 issue of the journal Science, the researchers explain how they connected the posterior parietal cortex of one patient, Erik G. Sorto, to a computer that acted as a kind of artificial motor cortex. The computer used specific signals from the parietal cortex to detect what kind of movement Sorto intended to make, and then translated that into signals for the robotic arm.
The concept of a bionic arm tapping into a new part of the brain for smooth movements likely refers to advancements in neuroprosthetics, which are devices that interface directly with the nervous system to restore motor function in individuals with limb loss or paralysis. Here’s a breakdown of the key elements involved:
1. **Bionic Arm**: A bionic arm is a prosthetic limb that incorporates advanced technology, such as robotics, sensors, and artificial intelligence, to mimic the function of a natural arm. These devices can be controlled by the user’s neural signals, enabling them to perform a wide range of movements with precision and dexterity.
2. **New Part of the Brain**: Traditional prosthetic limbs typically rely on signals from the remaining muscles or nerves in the residual limb to control movement. However, recent advancements in neuroprosthetics have enabled the development of devices that interface directly with the brain, tapping into specific areas of the cerebral cortex responsible for motor control.
3. **Smooth Movements**: By leveraging sophisticated algorithms and machine learning techniques, modern bionic arms can interpret neural signals from the brain with greater accuracy and efficiency. This allows users to perform movements with smoothness and fluidity, approaching the natural range of motion and coordination observed in biological limbs.
4. **Brain-Computer Interface (BCI)**: The technology enabling this level of control is known as a brain-computer interface, which establishes a direct communication pathway between the brain and external devices. BCIs can decode neural activity recorded from the motor cortex and translate it into commands to control the movement of the bionic arm in real-time.
5. **Neuroplasticity and Adaptation**: As users gain experience with their bionic arms, their brains undergo adaptive changes known as neuroplasticity. This allows them to learn new motor skills and optimize the control of their prosthetic limbs over time, leading to smoother and more intuitive movements.
Overall, the concept of a bionic arm tapping into a new part of the brain for smooth movements represents a significant breakthrough in the field of neuroprosthetics, offering individuals with limb loss or paralysis unprecedented levels of mobility and functionality. Continued research and innovation in this area hold promise for further enhancing the capabilities and usability of bionic limbs in the future.