Activation of the human mirror neuron system during the observation of the manipulation of virtual tools in the absence of a visible effector limb.

This work explores the mirror neuron system activity produced by the observation of virtual tool manipulations in the absence of a visible effector limb. Functional MRI data was obtained from healthy right-handed participants who manipulated a virtual paddle in the context of a digital game and watched replays of their actions. The results show how action observation produced extended bilateral activations in the parietofrontal mirror neuron system. At the same time, three regions in the left hemisphere (in the primary motor and the primary somatosensory cortex, the supplementary motor area and the dorsolateral prefrontal cortex) showed a reduced BOLD, possibly related with the prevention of inappropriate motor execution. These results can be of interest for researchers and developers working in the field of action observation neurorehabilitation.

A low cost fMRI-compatible tracking system using the Nintendo Wii remote.

It is sometimes necessary during functional magnetic resonance imaging (fMRI) experiments to capture different movements made by the subjects, e.g. to enable them to control an item or to analyze its kinematics. The aim of this work is to present an inexpensive hand tracking system suitable for use in a high field MRI environment. It works by introducing only one light-emitting diode (LED) in the magnet room, and by receiving its signal with a Nintendo Wii remote (the primary controller for the Nintendo Wii console) placed outside in the control room. Thus, it is possible to take high spatial and temporal resolution registers of a moving point that, in this case, is held by the hand. We tested it using a ball and racket virtual game inside a 3 Tesla MRI scanner to demonstrate the usefulness of the system. The results show the involvement of a number of areas (mainly occipital and frontal, but also parietal and temporal) when subjects are trying to stop an object that is approaching from a first person perspective, matching previous studies performed with related visuomotor tasks. The system presented here is easy to implement, easy to operate and does not produce important head movements or artifacts in the acquired images. Given its low cost and ready availability, the method described here is ideal for use in basic and clinical fMRI research to track one or more moving points that can correspond to limbs, fingers or any other object whose position needs to be known.