Martha G Garcia-Garcia, Cesar Marquez-Chin, Milos R Popovic
In the development of brain-machine interfaces (BMI), operant conditioning of neural activity is a strategy that has recently re-emerged from the need to design BMI systems that feel natural and intuitive to the user. In this strategy, a single cortical neuron is conditioned to produce an activity pattern that determines when the BMI is triggered.
Rats are implanted with an electrode array in the neocortex (top Figure) and trained to trigger a reward dispenser by activating a single cortical neuron at progressively higher firing rates, resulting in a typical learning curve (bottom Figure). Neurons are then classified into subgroups based on their electrophysiological characteristics.
The purpose of this project is to find neurons that perform reliably in a given BMI task. In addition, operant conditioning of single neuron activity facilitates BMI implementation and usability.
Cesar Marquez-Chin, Lazar Jovanovic, Milos R Popovic,
Recent evidence suggest that the integration of brain-computer interacting technologies into the motor rehabilitation after paralysis can result in greater and/or faster outcomes.
We are currently developing and testing the efficacy of functional electrical stimulation therapy (FEST), triggered by the activity of the brain, to restore voluntary movement of the arm and hand after spinal cord injury and stroke. Using brain-computer interfacing technology we identify a person's intention to move the arm and/or hand by analyzing the electroencephalographic (EEG) activity. Immediately after this, we trigger a complex sequence of electrical pulses applied to different muscles to produce the intended action. The use of electrical stimulation is reduced gradually as the ability to move is restored and it is discontinued completely at the end of this short-term therapeutic intervention.
Our first results have allowed us to see significant improvements in even cases that typically are unable to participate in other forms of therapy.
C. Marquez-Chin, A. Marquis, and M.R. Popovic, “EEG-triggered functional electrical stimulation therapy for restoring upper limb function in chronic stroke with severe hemiplegia,” Neurological Medicine - Journal,
ID9145213, 11 pages, 2016.