Hand Shape Representations in the Human Posterior Parietal Cortex

Humans shape their hands to grasp, manipulate objects, and to communicate. From nonhuman primate studies, we know that visual and motor properties for grasps can be derived from cells in the posterior parietal cortex (PPC). Are non-grasp-related hand shapes in humans represented similarly? Here we show for the first time how single neurons in the PPC of humans are selective for particular imagined hand shapes independent of graspable objects. We find that motor imagery to shape the hand can be successfully decoded from the PPC by implementing a version of the popular Rock-Paper-Scissors game and its extension Rock-Paper-Scissors-Lizard-Spock. By simultaneous presentation of visual and auditory cues, we can discriminate motor imagery from visual information and show differences in auditory and visual information processing in the PPC. These results also demonstrate that neural signals from human PPC can be used to drive a dexterous cortical neuroprosthesis

Decoding Motor Imagery from the Posterior Parietal Cortex of a Tetraplegic Human

Nonhuman primate and human studies have suggested that populations of neurons in the posterior parietal cortex (PPC) may represent high-level aspects of action planning that can be used to control external devices as part of a brain-machine interface. However, there is no direct neuron-recording evidence that human PPC is involved in action planning, and the suitability of these signals for neuroprosthetic control has not been tested.We recorded neural population activity with arrays of microelectrodes implanted in the PPC of a tetraplegic subject. Motor imagery could be decoded from these neural populations, including imagined goals, trajectories, and types of movement.These findings indicate that the PPC of humans represents high-level, cognitive aspects of action and that the PPC can be a rich source for cognitive control signals for neural prosthetics that assist paralyzed patients

Adults with cerebral palsy: A workshop to define the challenges of treating and preventing secondary musculoskeletal and neuromuscular complications in this rapidly growing population

Although the neurological injury associated with cerebral palsy (CP) is non-progressive, adults with the disorder often develop musculoskeletal and neurological symptoms, such as severe pain, chronic fatigue, and a premature decline in mobility and function, as they age. Little is known about how to manage, much less prevent, these symptoms. This paper summarizes the findings of a multi-disciplinary workshop, sponsored by the Cerebral Palsy International Research Foundation, the American Academy for Cerebral Palsy and Developmental Medicine, and Reaching for the Stars, convened to review current knowledge and begin to develop a blueprint for future research. The goals of the workshop were to (1) define the current incidence and prevalence of CP, (2) review the known complications for persons aging with CP, (3) review current understanding of physiological processes that may contribute to loss of function and premature aging in CP, (4) evaluate current treatment interventions in terms of long-term outcomes, (5) identify cutting-edge technologies in neurorehabilitation that may help prevent or treat the effects of accelerated aging for persons diagnosed with CP, and (6) identify strategies to ensure that individuals with CP receive evidence-based care as they transition from pediatric to adult-care services. © 2009 Mac Keith Press