MSGID: 1:317/3 6476cd75   
   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Flexible nanoelectrodes can provide fine-grained brain stimulation   
    Engineers' device is gentle on neurons, could serve as sensory prosthesis   
      
      
     Date:   
         May 30, 2023   
     Source:   
         Rice University   
     Summary:   
         Engineers have developed ultraflexible implantable nanoelectrodes   
         that can administer long-term, fine-grained brain stimulation.   
      
      
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   FULL STORY   
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   Conventional implantable medical devices designed for brain stimulation   
   are often too rigid and bulky for what is one of the body's softest and   
   most delicate tissues.   
      
   To address the problem, Rice University engineers have developed minimally   
   invasive, ultraflexible nanoelectrodes that could serve as an implanted   
   platform for administering long-term, high-resolution stimulation therapy.   
      
   According to a study published in Cell Reports, the tiny implantable   
   devices formed stable, long-lasting and seamless tissue-electrode   
   interfaces with minimal scarring or degradation in rodents. The devices   
   delivered electrical pulses that match neuronal signaling patterns and   
   amplitudes more closely than stimuli from conventional intracortical   
   electrodes.   
      
   The devices' high biocompatibility and precise spatiotemporal stimulus   
   control could enable the development of new brain stimulation therapies   
   such as neuronal prostheses for patients with impaired sensory or motor   
   functions.   
      
   "This paper uses imaging, behavioral and histological techniques to   
   show how these tissue-integrated electrodes improve the efficacy of   
   stimulation," said Lan Luan, an assistant professor of electrical and   
   computer engineering and a corresponding author on the study. "Our   
   electrode delivers tiny electrical pulses to excite neural activity in   
   a very controllable manner.   
      
   "We were able to reduce the current necessary to elicit neuronal   
   activation by more than an order of magnitude. Pulses can be as subtle   
   as a couple hundred microseconds in duration and one or two microamps   
   in amplitude."  The new electrode design developed by researchers in the   
   Rice Neuroengineering Initiative represents a significant improvement   
   over conventional implantable electrodes used to treat conditions such as   
   Parkinson's disease, epilepsy and obsessive-compulsive disorder, which can   
   cause adverse tissue responses and unintended changes in neural activity.   
      
   "Conventional electrodes are very invasive," said Chong Xie, an associate   
   professor of electrical and computer engineering and a corresponding   
   author of the study. "They recruit thousands or even millions of neurons   
   at a time.   
      
   "Each of those neurons is supposed to have their own tune and coordinate   
   in a specific pattern. But when you shock them all at the same time,   
   you're basically disrupting their function. In some cases that works fine   
   for you and has the desired therapeutic effect. But if, for example,   
   you want to encode sensory information, you need much greater control   
   over the stimuli."  Xie likened stimulation via conventional electrodes   
   with the disruptive effect of "blowing an airhorn in everyone's ear or   
   having a loudspeaker blaring" in a roomful of people.   
      
   "We used to have this very big loudspeaker, and now everyone has an   
   earpiece," he said.   
      
   The ability to adjust the frequency, duration and intensity of the   
   signals could enable the development of novel sensory prosthetic devices.   
      
   "Neuron activation is more diffuse if you use a larger current," Luan   
   said. "We were able to reduce the current and showed that we have a   
   much more focused activation. This can translate to higher-resolution   
   stimulation devices."  Luan and Xie are core members of the Rice   
   Neuroengineering Initiative and their labs are also collaborating on the   
   development of an implantable visual prosthetic device for blind patients.   
      
   "Envision one day being able to implant electrode arrays to restore   
   impaired sensory function: The more focused and deliberate is the   
   activation of the neurons, the more precise the sensation you're   
   generating," Luan said.   
      
   An earlier iteration of the devices was used to record brain activity.   
      
   "We have had a series of publications showing this intimate tissue   
   integration enabled by our electrode's ultraflexible design really   
   improves our ability to record brain activity for longer durations and   
   with better signal-to-noise ratios," said Luan, who has been promoted   
   to associate professor effective July 1.   
      
   Electrical and computer engineering postdoctoral associate Roy Lycke   
   and graduate student Robin Kim are lead authors on the study.   
      
   The National Institute of Neurological Disorders and Stroke (R01NS109361,   
   U01 NS115588) and Rice internal funds supported the research.   
      
       * RELATED_TOPICS   
             o Mind_&_Brain   
                   # Brain-Computer_Interfaces # Perception # Intelligence   
                   # Neuroscience   
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                   # Energy_Technology # Medical_Technology # Technology #   
                   Energy_and_Resources   
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             o Volcanic_rock o Brain_damage o Deep_brain_stimulation o   
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             o Thalamus   
      
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   Story Source: Materials provided by Rice_University. Original written   
   by Silvia Cernea Clark.   
      
   Note: Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Roy Lycke, Robin Kim, Pavlo Zolotavin, Jon Montes, Yingchu Sun, Aron   
         Koszeghy, Esra Altun, Brian Noble, Rongkang Yin, Fei He, Nelson   
         Totah, Chong Xie, Lan Luan. Low-threshold, high-resolution,   
         chronically stable intracortical microstimulation by   
         ultraflexible electrodes. Cell Reports, 2023; 42 (6): 112554 DOI:   
         10.1016/j.celrep.2023.112554   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2023/05/230530174315.htm   
      
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