Design and characterization of a protein fold switching network.

To better understand how amino acid sequence encodes protein structure, we engineered mutational pathways that connect three common folds (3α, β-grasp, and α/β-plait). The structures of proteins at high sequence-identity intersections in the pathways (nodes) were determined using NMR spectroscopy and analyzed for stability and function. To generate nodes, the amino acid sequence encoding a smaller fold is embedded in the structure of an ~50% larger fold and a new sequence compatible with two sets of native interactions is designed.

Rapid and reversible recruitment of early visual cortex for touch.

Background: The loss of vision has been associated with enhanced performance in non-visual tasks such as tactile discrimination and sound localization. Current evidence suggests that these functional gains are linked to the recruitment of the occipital visual cortex for non-visual processing, but the neurophysiological mechanisms underlying these crossmodal changes remain uncertain. One possible explanation is that visual deprivation is associated with an unmasking of non-visual input into visual cortex.

Time-dependent changes in cortical excitability after prolonged visual deprivation.

Transcranial magnetic stimulation applied to the occipital cortex can elicit phosphenes. Changes in the phosphene threshold provide a measure of visual cortex excitability. Phosphene threshold was measured in participants blindfolded for five consecutive days to assess the effects of prolonged visual deprivation on visual cortical excitability.

Braille character discrimination in blindfolded human subjects.

Visual deprivation may lead to enhanced performance in other sensory modalities. Whether this is the case in the tactile modality is controversial and may depend upon specific training and experience. We compared the performance of sighted subjects on a Braille character discrimination task to that of normal individuals blindfolded for a period of five days.