Bidirectional interactions between the brain and implantable computers. Eberhard E. Fetz

We are investigating the consequences of bidirectional connections produced by an autonomous implantable recurrent brain-computer interface [R-BCI] that operates continuously during free behavior and generates activity-dependent stimulation of the brain or muscles. This device consists of battery-powered electronics connected to electrodes that record the activity of motor cortex cells and/or muscles. The neural activity is processed by a programmable computer chip and can be converted in real-time to activity-contingent stimuli delivered to nervous system sites or muscles. A promising application is to bridge impaired biological connections, a paradigm recently demonstrated for cortically controlled electrical stimulation of paralyzed forearm muscles (Moritz et al, Nature, 2008).  A second application of the R-BCI is to produce Hebbian plasticity through spike-triggered stimulation, which can strengthen physiological connections (Jackson et al, Nature, 2006). Recent work has shown that similar plastic changes can be produced in cortex by EMG-triggered stimulation (Lucas & Fetz, J. Neurosci. 2013) and in the strength of corticospinal connections by cortically triggered intraspinal stimulation. The novel R-BCI paradigm has numerous potential applications, depending on the input signals, the computed transform and the output targets.

Eberhard E. Fetz, Ph.D.
Departments of Physiology & Biophysics and Bioengineering
and Washington National Primate Research Center
University of Washington
Seattle, WA 98195