Volitional phase control of neural oscillations using a brain-machine interface

Strong oscillations present in local field potential (LFP) recordings at specific frequencies are thought to be correlated with behavior and involved in communication and coordination across brain areas. LFP-based brain-machine-interfaces (BMIs) lay the groundwork for using closed-loop BMIs to study oscillations across brain regions and to test hypotheses about the rigidity of relationships between oscillations. In this study, we demonstrate the first reported use of inter-regional phase differences to control a BMI. In a one-dimensional two target task where phase difference is mapped to cursor velocity, we show that a macaque monkey, implanted with microwire arrays bilaterally is able to control phase extracted from distal electrodes in left motor cortex (M1) and right dorsal pre-motor cortex (PMd) at frequencies of 20 Hz, 31 Hz, and 40 Hz well above chance, but not at 10 Hz and 50 Hz. Our results imply that within the beta band (15-40Hz) in motor cortex and pre-motor cortex, phase relationships can be volitionally controlled.