In a recent set of clinically relevant human experiments of an intracortical

brain-machine interface, a more practical two-state (point and click) neural decoder was trained using neural activity measured in the absence of overt movement (Kim et al., 2011 and Simeral et al., 2011). In order to train the trajectory generation Selisistat ic50 component of the decoder, human subjects with tetraplegia were instructed to observe computer generated movements of a visual cursor while imagining that they were controlling the cursor. The patients were instructed to imagine squeezing or opening their hand in response to a discrete visual cue in order to train the click functionality. Despite the lack of overt movement during training, the patients were able to achieve successful control of the BMI with one participant reaching a 97% success rate. These studies clearly demonstrate the utility of the neural responses measured during observation and imagination of action for the creation of see more neural decoders. Ultimately, the goal of all BMI research is to provide individuals with severe motor disabilities a device that can adequately replace lost afferent as well as efferent functionality. The potential utility of incorporating additional forms of sensory feedback, including tactile and proprioceptive feedback, to BMIs that typically incorporate feedback only from vision has been

widely suggested (Abbott, 2006, Gilja et al., 2011 and Hatsopoulos and Donoghue, 2009). In fact, some have begun to explore methodologies to integrate different forms of sensory feedback in BMI systems. Direct electrical stimulation of the somatosensory cortex via microelectrodes has been shown to elicit discernable sensory

percepts in primates for the purpose of frequency discrimination (Romo et al., 1998) or cuing of upcoming reach targets (Fitzsimmons et al., 2007). Similarly, Dihillon and Horch reported that amputees were able to discern either the grip force or joint position of a prosthetic arm based on the frequency of electrical stimulation in residual peripheral nerves (Dhillon and Horch, 2005). More recently, O’Doherty et al. have effectively combined an efferent intracortical brain-machine interface Thiamine-diphosphate kinase with somatosensory feedback provided by direct intracortical microstimuation (ICMS) of primary somatosensory cortex (O’Doherty et al., 2009 and O’Doherty et al., 2011). Monkeys were trained to move a visual cursor from a central target to one of two peripheral targets based on the presence of a vibrotactile cue. After a training period of 15 sessions, the vibrotactile cue was replaced by ICMS. After a period of relearning (20 sessions), the monkeys achieved a task success rate (90%) in the ICMS condition that was equal to the performance level achieved with the vibrotactile stimulus (O’Doherty et al., 2009). In a later study (O’Doherty et al.