Movement related directional tuning from broadband electrocorticography in humans

Directional tuning is the tendency for cortical neurons to exhibit a peak firing rate when a limb is moved in a preferred direction. This phenomenon has been used to underpin decoding strategies in many brain-machine interface (BMI) systems. Although it is well established that individual motor neurons can be decoded using directional tuning, this is not as well understood at the scale of cortical local field potentials (LFPs). This study investigates the directional tuning properties of broadband electrocorticography (ECoG) recorded during a center-out task from two human participants. Selected bipolar ECoG channels demonstrated directional tuning in signal power from 85 - 250 Hz for both subjects. Directional tuning was observed across sensorimotor cortex, as well as frontal areas of cortex. The presence of directional tuning in broadband ECoG suggests the potential use of tuning curves as the basis of a LFP based BMI system.