Neural networks of response shifting: influence of task speed and stimulus material.

Functional magnetic resonance imaging (fMRI) was used in 14 healthy subjects to measure brain activation, while response shifting was performed. In the activation phase, subjects were asked to shift their attention between two different types of visually presented stimuli. In the baseline phase, subjects were required to attend to one stimulus type only.

Human prefrontal and sensory cortical activity during divided attention tasks.

In our natural environment, the ability to divide attention is essential since we attend simultaneously to a number of sensory modalities, e.g., to visual and auditory stimuli.

Vestibular evoked potentials from the vertical semicircular canals in humans evoked by roll-axis rotation in microgravity and under 1-G.

Vestibular evoked potentials during rotation of human subjects around their naso-occipital roll-axis were recorded. The effect of stimulating the vertical semicircular canals and otolithic stimulation was investigated by comparing the evoked potentials obtained under the 1-G condition with those recorded in microgravity conditions. Subjects lay on their side with the head in the center of rotation and were tilted feet upward (roll up) and back into the lying position (roll down).