Real-time prediction of hand trajectory by ensembles of cortical neurons in primates.

Signals derived from the rat motor cortex can be used for controlling one-dimensional movements of a robot arm. It remains unknown, however, whether real-time processing of cortical signals can be employed to reproduce, in a robotic device, the kind of complex arm movements used by primates to reach objects in space. Here we recorded the simultaneous activity of large populations of neurons, distributed in the premotor, primary motor and posterior parietal cortical areas, as non-human primates performed two distinct motor tasks. Accurate real-time predictions of one- and three-dimensional arm movement trajectories were obtained by applying both linear and nonlinear algorithms to cortical neuronal ensemble activity recorded from each animal. In addition, cortically derived signals were successfully used for real-time control of robotic devices, both locally and through the Internet. These results suggest that long-term control of complex prosthetic robot arm movements can be achieved by simple real-time transformations of neuronal population signals derived from multiple cortical areas in primates.

Video-feedback and personal attribution in anorexic, depressed and normal viewers.

Video-feedback has been shown to be particularly influential in changing bodily awareness and causal attribution by confronting participants with a concrete 'public' self-image. Body-image disturbance and denial are major aspects of patients suffering with anorexia nervosa. It was predicted that video-feedback should alter these attitudes in this group and result in a more realistic self-appraisal. Anorexics respond to video-feedback with a reduction in self-esteem whereas normal controls displayed an increase in self-esteem and depressed patients perceived themselves negatively both before and after video-feedback. It is concluded that video-feedback may prove to be a useful technique in the treatment of body-image disturbance in anorexic patients.