Biomarkers in Neural Disorders

Eye blink responses will be induced using standard stimulating electrodes employed in surface electromyography (EMG). The subjects will recline with their eyes gently closed. Sticky electrodes will be placed to the left and below the left eye. 6 different facial regions will be stimulated. The electrical stimulation will be kept constant during the test sessions. To prevent habituation, the stimuli will be delivered randomly at intervals of 45-60 sec. Four 0.2 msec pulses will be presented. In some cases, paired pulse stimulation will be performed, and a conditioning stimulus will be applied to the target facial regions at the following intervals: 10, 200, 400, 600 and 800 msec. 4 pulses will be presented at each stimulus interval with randomized interval and pulse sequences.

Olfactory testing will be performed using standard tests. The University of Pennsylvania Smell Identification Test (UPSIT) assesses a subjects ability to identify odors in a forced choice format. The Snap and Sniff Threshold Test provides a threshold measure of phenyl ethyl alcohol. Short-term odor memory will be assessed using a standardized 12-item four-alternative forced-choice Odor Memory Test. This non-lexical test employs 10-, 30-, and 60-second delay intervals between the presentation of the target odorant and the first of four successively presented odors from which the target is to be selected.

During a 2-hour visual deprivation period, subjects will wear comfortable light-tight goggles with lenses that have been blackened by flat black paint. Subjects will be given the opportunity to recline comfortable in a padded reclining chair during this time.

Electrical stimulation will be applied to a nerve of your arm. Sticky electrode pads will also be placed on a hand muscle. You will receive electrical stimulations that lasts less than a second. The stimulations will make your muscle twitch.