Perceptual learning specific for orientation and spatial frequency.

Several examples of 'perceptual learning' (improvement of some perceptual task with practice) have been reported. These studies are of great interest for neurological research because they demonstrate plasticity of the nervous system. Even for apparently basic perceptual tasks, such as visual acuity or vernier acuity, practice can facilitate a neural change which enhances performance. One question in this field is where does this learning occur? Indications about the possible neural site of a learning process may be derived from its specificity for some particular stimulus parameters. For instance, there is a hint that learning in global stereopsis may occur at a stage where visual information is processed by mechanisms selectively sensitive to different stimulus orientations. We report here an experiment on perceptual learning in the discrimination of gratings of different waveform. Our findings show that learning is specific for both the orientation and the spatial frequency of the practice stimulus.