, 2005). By shifting the position of the reference objects relative to the gaze fixation target, it was possible to determine whether neurons represented the position of missing components in viewer-centered

or object-centered spatial coordinates. If neurons coded the position of missing object components in viewer-centered coordinates, their activity would vary as a function of whether they were located to the left or right of the gaze fixation target (at the midline of viewer-centered frames of learn more reference). If, instead, neurons coded the position of missing object components in object-centered coordinates, their activity would vary as a function of whether components were missing from the left or right side of the copy object, relative to its intrinsic midline. A population of neurons in area 7a was found which represented the position of missing components in object-centered coordinates, relative to the midline of the object (Chafee et al., 2007). Kinase Inhibitor Library These neurons were similarly activated during the copy period whenever the missing component was located on a preferred side of the copy object, regardless of where the copy object was presented in viewer-centered space (Fig. 7A). The above

data provided evidence that the parietal neurons supported a spatial cognitive process during the object construction task that analyzed object structure and that represented the results of the analysis in object-centered coordinates. However, parietal neurons were heterogeneous in terms of the spatial coordinate

system they used to represent space, and neurons coding position in viewer- and object-centered position were both present in area 7a (Chafee et al., 2007). A decoding analysis quantified the information carried by the activity of the two simultaneously active populations in their respective coordinate systems, and found that variation in viewer-centered information preceded and could predict variation in object-centered Diflunisal information over time within a trial (Crowe et al., 2008). This observation was consistent with the hypothesis that spatial information provided by the visual input coding position, initially in viewer-centered (retinocentric) coordinates, was converted into spatial information coding position in object-centered coordinates over time, and that a correlate of this transform could be detected in parietal cortex. The above neural data provide evidence that parietal neurons encode spatial information that is the product of a spatial cognitive analysis applied to the visual input to meet a specific behavioural objective. That functional conclusion was further substantiated by the results of neurophysiological recordings in parietal area 7a of monkeys performing a visual maze task (Fig. 8).