Toward a fully implantable ecosystem for adaptive neuromodulation in humans

Recently, Gerwin Schalk, Director of the Chen Frontier Lab for Applied Neurotechnology which is affiliated with the Tianqiao and Chrissy Chen Institute (TCCI), was the lead author on an article which describes initial work done towards creating an ecosystem for adaptive neuromodulation in humans. The paper, entitled “Toward a fully implantable ecosystem for adaptive neuromodulation in humans: Preliminary experience with the CorTec BrainInterchange device in a canine model” was published in the December 19,, 2022 issue of the journal Frontiers in Neuroscience.


Neural interface technology, such as brain computer interfaces, allows scientists to measure activity from the nervous system and then stimulate it, creating closed-loop systems that establish artificial connections within the body or to the outside world.


Adaptive neuromodulation, when this interface is changed dynamically in response to one’s neurophysiologic state, has opened new ways to study brain function and to treat neurological disorders. Adaptive neuromodulation research is currently in an early stage, with relatively modest knowledge about how different areas in the brain interact to produce specific behaviors, how these interactions are affected by disease, and how to electrically modulate them to normalize pathologic behavior. Researchers today know very little about ideal targets for sensing or stimulation, the optimal adaptive protocol, or the best parameters of stimulation. Therefore, human studies for treatment are essentially forced to be expensive multi-year experiments based on trial and error. This unfortunate reality demands, and in practice requires, a readily available and easy-to-use general-purpose adaptive neuromodulation platform.


In this study, researchers selected a device called the BrainInterchange (BIC) designed by CorTec to address the need for complex and flexible human experimentation. BIC supports 32 channels that are sampled at 1 kHz and are digitized at 16 bit (74 nV resolution). In terms of software, the BCI2000 system, a general-purpose software platform for closed-loop neuromodulation and similar experiments, was adopted. It uses outputs to determine the timing or nature of the feedback to the brain through sensory or electrical stimulation. These functions are highly adaptable and perform well even in demanding situations.


For this research, BIC electrodes were implanted in the brains of beagles. Based on post-surgical validation of brain signal recordings and implant parameters, the hardware capabilities of the BIC device are fully supported by the BCI2000 software, and the BIC/BCI2000 device was shown to record and process brain signals during free behavior. Meanwhile the device can perform all of the recording, processing, visualization and stimulation functions of the BCI2000, it connects to a local WiFi network, and can be controlled using remote-control software. The transmission unit, portable PC, and associated battery are light enough that they can be carried by a medium-sized animal such as a dog using a harness.


It is anticipated that with the progress detailed in the paper and following full technical and clinical validation and with development of technical, clinical, and regulatory protocols, this work will serve as the basis for the first comprehensive ecosystem for adaptive neurotechnology research in humans. This should make it easier for research groups to develop new neuromodulation protocols that address the devastating effects of different neurological disorders.


The biggest challenge for further clinical development of invasive neuromodulation protocols in humans is the substantial depth and breadth of technical, experimental, clinical, and regulatory expertise that must come together to translate scientific understanding into a device available for human use. This research started prior to professor Gerwin Schalk’s role as the Director of Chen Frontier Lab, which is now an autonomous platform for scientific research. The Lab also serves as the experimental ground for translating scientific understandings into applicable technologies and will, as always, focus on developing technologies and devices that can facilitate insights into human brain and improve human life experiences.


Read the paper in the journal Frontiers in Neuroscience