Past fMRI Studies

Two fMRI studies that together included more than 30 subjects were carried out with fMRI compatible haptic robot. The first study observed human brain activation during reaching in a virtual environment. The second study observed brain activation during the planning and execution phases of a pattern connection task.

Rest before reaching - RR Reaching - R
Rest before extending - RE Extending - E

For the first study, a virtual environment application was programmed where a human subject could perform reaching movements. The haptic dimensions of the virtual room are 140 mm x 100 mm x 80 mm. The position of a white cursor ball in the virtual room reflects the position of the end-effector point of the fMRI compatible haptic robot. The virtual environment session consists of four tasks: rest before reaching (RR), target reaching (R), rest before extending (RE) and extending (E) - non-targeted reaching. During the RR and RE tasks the edges of the room are colored red, indicating that the subject should rest. The subject is instructed to observe the room and not perform any movements. When the edges of the room turn green, the subject performs reaching (R task) and arm extension (E task) movements. It is essential that the subject feels the impact with the target located on the back wall during R and E. A complete session consists of eight blocks, each containing four of the above tasks. The duration of each block is 2 min., with 30 s for each task in the block.

Comparison of reaching to the rest reaching task (R–RR) revealed activations in the left primary sensorimotor cortex (SM1), bilateral premotor cortex (PMC), inferior frontal gyrus (IFG), supplementary motor area (SMA), inferior and superior posterior parietal cortex (PPC), visual cortex, left basal ganglia (BG) and predominantly the right cerebellar hemisphere. During extending (E–RE), similar but less prominent brain activations were found, including right SM1, bilateral PMC, IFG, SMA, inferior PPC, visual cortex and right CRB. Direct comparison of reaching to extending (R–E) revealed that areas showing greater activation during R were the bilateral prefrontal cortex, SMA, right visual cortex and right CRB.

Pattern 1, Orientation 0° Pattern 1, Orientation 120° Pattern 1, Orientation 240°
Pattern 2, Orientation 0° Pattern 2, Orientation 120° Pattern 2, Orientation 240°

The second study was carried out on a Siemens Verio 3 T fMRI scanner of the International Advanced Telecommunication Research Institute (ATR) Kyoto, Japan. The aim of this study was to observe human brain activation during the planing and execution phases of cursor movement through a given pattern in a virtual environment. The cursor again reflects the position of the end-effector point of the fMRI-compatible haptic robot. In the virtual environment task, a subject had to connect six given points with a smooth movement from the Start to the End point. The movement had to be as fast and as accurate as possible. There were two different patterns of points in three orientations (0°, 120° and 240°) that appeared randomly on a screen. Each subject was presented with 144 trials. After each 36 trials, the subject had a 5-minute rest. Behavioral data acquired by the haptic robot shows that subjects use different trajectories to connect the same pattern. The next step we are trying to do is to decode these different trajectories from fMRI data. A sample of the acquired trajectories can be seen below.