Learning is based on the remodeling of neural connections in the brain. The purpose of the present study was to examine the extent to which training-induced improvements in tactile frequency discrimination in humans are correlated with an increase of cortical representations in the primary somatosensory cortex. Healthy male subjects (n = 16) were trained in a tactile frequency discrimination task of the left ring finger. During the first 15 days of training, there was a steep improvement in frequency discrimination, which generalized from the trained finger to its homologue on the opposite hand, and to a lesser extent, to the other fingers on both hands. During the following 15 days of training, there was only a minor improvement in tactile frequency discrimination. Retention of improved performance in frequency discrimination 30 days after training was demonstrated for all digits. Cortical finger representation in the primary somatosensory cortex, as measured by magnetic source imaging, did not change during training. Because of the generalized training effect and the lack of detectable increase in the cortical field evoked from the trained finger, we assume that skill improvement was mediated predominantly by regions outside the primary somatosensory cortex.

Spatial asymmetries in tactile discrimination of line orientation: a comparison of the sighted, visually impaired, and blind. Thresholds for tactile discrimination of stimulus orientation discrepancy from standard or referent vertical, horizontal, and diagonal orientations were determined for sighted, visually impaired, and blind subject groups. The stimuli were presented to the ventral distal portion of the tip of the subject's left index finger via an Optacon. Although the subject groups did not differ in overall discrimination accuracy, for each group the deviations from vertical and horizontal standard orientations were discriminated reliably more accurately than the deviations from standard diagonals, ie the oblique effect was obtained. The bases for this tactual spatial anisotrophic effect appear to reflect both sensory--neurological and experiential factors. Published in Perception (1988)

tumor. Sensory modalities may include visual, auditory, tactile, olfactory, and taste. Perceptual learning forms important foundations of complex cognitive Perceptual learning is the learning of perception skills, such as differentiating two musical tones from one another or categorizations of spatial and temporal patterns relevant to real-world expertise. Examples of this may include reading, seeing relations among chess pieces, and knowing whether or not an X-ray image shows a tumor. Sensory modalities may include visual, auditory, tactile, olfacto Perceptual learning is the learning of perception skills, such as differentiating two musical tones from one another or categorizations of spatial and temporal patterns relevant to real-world expertise. Examples of this may include reading, seeing relations among chess pieces, and knowing whether or not an X-ray image shows a tumor. Sensory modalities may include visual, auditory, tactile, olfactory, and taste. Perceptual learning forms important foundations of complex cognitive processes (i.e., language) and interacts with other kinds of learning to produce perceptual expertise. Underlying perceptual learning are changes in the neural circuitry. The ability for perceptual learning is retained throughout life.