This cancellation of self-generated sensory INCB024360 clinical trial feedback would be used to increase the detection of any environmentally generated sensory information (Wolpert and Flanagan, 2001). One of the ways that this theory was tested was by using the observation that self-generated tickle was much less ticklish than externally generated tickle. By using robotic manipulanda to separate the self-generated motion to perform the tickle and the tactile input on the skin (giving rise to the tickle sensation), it was demonstrated that as the sensation was changed from the self-generated motion by adding small delays or changes in movement direction, the tactile input became

more ticklish (Blakemore et al., 1999). This demonstrates that the prediction mechanism used in sensory perception was precise, both spatially and temporally. A similar effect was found in force generation, where selleck products self-generated forces are felt less intensively. This was used

to explain the finding of force escalation (Shergill et al., 2003). Support for this idea that the efference copy is used to predict the sensory consequences of movement and remove this for sensory perception has also been found in self-generated head movements where the predicted cancellation signal is subtracted in the vestibular nuclei (Roy and Cullen, 2001 and Roy and Cullen, 2004). Research on eye movements has also provided strong evidence for the use of efference

copy in a manner that illustrates many of the properties of the forward model, in particular for this transformation from motor to sensory representation (Roy and Cullen, 2001, Roy and Cullen, 2004, Sommer and Wurtz, 2002 and Sommer and Wurtz, 2006). In the visual system, the change in afferent feedback produced by the movement of the eye needs to be determined Tryptophan synthase in order to discount accurately the self-generated movement (reafference) from the externally generated movement in the world (exafference). This could be done using the motor signals sent to the muscle of the eye. Saccades are generated from the frontal eye field (FEF) via descending drive through the superior colliculus (SC) (for a review see Andersen and Buneo, 2002); therefore, it was hypothesized that signals from the SC could act as efference copy back to the FEF (Sommer and Wurtz, 2002). One candidate pathway, therefore, was via the medial dorsal nucleus (MD) of the thalamus, which increases activity just prior to the saccade and signals the direction of the saccade (Sommer and Wurtz, 2004a) (Figure 2A). In the double-step saccade task (Figure 2B), two targets are flashed sequentially during fixation, to which the eye is then required to make a saccade to in sequence. The location of the second target is only available as a vector from the initial fixation position.