connection between The neurons in your brain enable you to do amazing things, from brushing your teeth to solving arithmetic equations. When these connections are damaged, often as a result of conditions such as stroke or traumatic brain injury, these abilities can be lost. However, direct activation of neurons with short current pulses can help reestablish these connections and potentially restore function.
Doctors currently use this technique, known as neurostimulation, to treat conditions such as Parkinson’s and depression. We believe that neurostimulation has the potential not only to treat symptoms, but also to heal a variety of diseases by repairing damaged connections. However, it is not clear how best to modulate the stimulation to specifically target damaged connections in the brain.
New forms of neurotechnology and statistical modeling developed over the years have made it possible to answer this question. Our team of biomedical engineers and statisticians used these tools to show that changes in neurons from neurostimulation depend on how they were originally connected. In other words, for neurostimulation to work, it must be tailored to each individual brain.
New technologies bring excitement to light
Deep brain stimulation is a form of neurostimulation currently used to treat Parkinson’s and depression.
To test which factors influence the effects of neurostimulation the most, we stimulated the brains of two monkeys and recorded how the connections between the different regions changed. We focused on brain regions involved in motor movement and sensory processing – regions that are often impaired in neurological disorders such as stroke.
We recorded our data using a massive neural interface – a device that sits directly on the surface of a living brain and records the activity of neurons underneath. Our neural interface was able to precisely stimulate each region through optogenetics, a technique that illuminates genetically engineered neurons to activate them. While not yet approved for human use, optogenetics has unique advantages over other forms of neurostimulation that make it particularly useful for understanding how stimuli affect the brain. This includes its ability to record high-quality electrical signals generated by the brain.
We then analyzed our data with an artificial intelligence algorithm designed to predict how pre-existing brain connections and various stimulus parameters would affect the brain.
This algorithm is similar to other AI techniques like deep learning, which find complex relationships in data that are difficult or impossible to see. But unlike these “black box” models, which make it impossible for researchers to understand how they reached their conclusions, our technique allows us to see why and how it makes predictions. Using this algorithm, we were able to test the various factors that influence connectivity changes and visualize how each of them contributed to the overall prediction of the deployed model. These factors included pauses between stimulation sessions, the distance between stimulation sites in the brain, and the area of the brain where the electrodes were placed.
We found that the existing connections in the brain, rather than how the stimulus was delivered, were the most important factor in predicting changes in the brain. This suggests that the unique properties of each individual brain are important in understanding how it responds to stimuli, pointing to the need for individualization of treatment to maximize its utility. This may sound like putting together the strength, frequency, and location of neurostimulation in each individual’s brain.
Why personalization matters
Brain stimulation can help some people recover after a stroke. BSIP/Universal Image Group/Getty Images
Brain stimulation has the potential to treat a variety of neurological disorders. Our work suggests that examining how existing brain connectivity affects neurostimulation response could be a new direction worth exploring further. We believe that altering nerve connections themselves for long-term effects as opposed to stimulating neurons for short-term changes in neurological activity can help treat conditions ranging from simply treating symptoms. .
One health condition for which privatization could improve brain stimulation treatments is stroke, which is a leading cause of severe long-term disability and death in the United States. If you do this before the two-week window, your chances of recovery drop significantly.
A failed 2008 clinical trial involving one of us on the Everest Trail investigated the possibility of using brain stimulation to prolong this recovery period and help stroke survivors regain mobility. helped. Based on our most recent study, we speculate that the clinical trial may have failed because the researchers applied the same general stimulation to all patients, rather than tailoring it to each individual brain.
Application of the same brain stimulation parameters can be worked out in rodent studies, but human brains are much more complex. While we cannot know for sure if the clinical trial failed for this reason, our research suggests that the stimuli may need to be more personalized to be effective.
Next steps to personalize brain stimulation
Our work shows that stitching treatments to each individual brain can help improve brain stimulation outcomes and suggests tools to study how neural connectivity affects stimulation. However, more research is needed to find out how individualization is achieved through the proper strengthening or weakening of specific neural connections.
It’s also worth noting that we’ve only tested our technology on two brain regions so far. We plan to repeat this study in other brain regions to see if our findings can be generalized to the brain and applied to a variety of neurological and psychological disorders. We are also in the process of using our neural interface and AI algorithms to design stimulation patterns that can evoke specific changes in the brain to repair bad connections.
The full potential of brain stimulation will not be realized until scientists better understand how it affects the brain. We believe that finding out how existing patterns of brain connectivity interact and change with stimulation may open the door to more treatments and therapies for neurological and psychiatric disorders.
This article is originally from . was published in conversation Through Azadeh Yazdan-Shahmorad, Alec Greaves-Tunnel and Julian Bloch at the University of Washington. Read the original article here.
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