An MR-Compatible Haptic Interface With Seven Degrees of Freedom

Functional magnetic resonance imaging (fMRI) is a powerful tool for neuroscience. It allows the visualization of active areas in the human brain. Combining this method with haptic interfaces allows one to conduct human motor control studies with an opportunity for standardized experimental conditions. However, only a small number of specialized MR-compatible haptic interfaces exist that were mostly built around specific research questions. The devices are designed for pure translational, rotational, or grasping movements. In this work, we present a novel MR-compatible haptic interface with seven degrees of freedom (DoF), which allows for both translations and rotations in three DoF each, as well as a two-finger precision grasp. The presented haptic interface is the first one with these capabilities and is designed as a universal tool for human motor control studies involving fMRI. It allows for the switching of the paradigm to reprogramming rather than redesigning when moving on to a new research question. We introduce its kinematics and control, along with results of MR compatibility tests and a preliminary fMRI study, showing the applicability of the device.