Abstract
Little is known about how intensive experience in discriminating exemplars from an object class changes the processing and representation of these objects in human visual cortex. Physiological studies in macaque visual cortex have reported effects of discrimination training on both the strength and the selectivity of neural responses. We investigated the effect of object discrimination training on the BOLD response in several regions of the human visual cortex. We trained 9 subjects during 10 daily sessions on the discrimination of shaded 3D objects from one of three novel object classes: ‘smoothies’, ‘spikies’, and ‘cubies’. All subjects showed an improvement of discrimination ability over training. Subjects were scanned using an 8-channel coil in a 3T scanner before and after training. During scanning, subjects performed an orthogonal task, detecting changes in object color. A comparison of the pre- and post-training scan sessions revealed that training increased the BOLD response (p < .001) for the trained object class relative to the response for the untrained classes in object-selective voxels (LOC). No consistent training effects were seen in other visual regions such as the right fusiform face area and early visual cortex. The training effect was restricted to a subset of the voxels in LOC. The localization of the training effects seemed to depend on the selectivity of voxels before training and on subjects' strategies. In conclusion, object discrimination training increases the BOLD response in object-selective regions of human visual cortex.