This is a single-visit non-invasive study of healthy volunteer subjects. Brain activity will be measured with infra-red light sensors attached to a cap worn on the head, while both ears are gently stimulated with plastic filaments.
The aim of this study is to localize and quantify brain activations from experimental stimulation of auricular points in pain-free volunteers. Investigators will stimulate auricular points for the shoulder, thumb, and lumbar spine with von Frey filaments and measure functional near-infrared spectroscopy (fNIRS) responses in the primary somatosensory (S1) and prefrontal cortex (PFC). This will test the hypothesis that stimulation across different points in the auricular cartography maps to distinct brain responses, an assumption underpinning AT theory. Stimulation of different ear points is anticipated to induce similar PFC responses, but activate distinct areas within the S1 homunculus, validating the concept of auricular cartography.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
80
Different points on both ears will be repeatedly stimulated with a plastic filament. This will be felt, but not be painful and should not result in lasting irritation.
University of Pittsburgh
Pittsburgh, Pennsylvania, United States
RECRUITINGfNIRS response, Lumbar spine vs. thumb auricular points
Calculated T-statistic for contrast of analyzed fNIRS signal change, comparing responses from stimulation of the ipsilateral ear at the auricular points corresponding to the lumbar-spine vs. thumb. A T-statistic of 0 indicates no difference; more positive scores mean stronger fNIRS signal change with stimulation of the lumbar point, compared to stimulation of the thumb point; more negative scores mean change with stimulation of the thumb, compared to the lumbar spine. This outcome is a number reflecting the overall magnitude of difference between stimulation points, calculated in one summary statistic. Dispersion measures cannot be calculated for the T-statistic in this analysis framework.
Time frame: 10 minutes
fNIRS response, shoulder vs. thumb auricular points
Calculated T-statistic for contrast of analyzed fNIRS signal change, comparing responses from stimulation of the ipsilateral ear at the auricular points corresponding to the shoulder vs. thumb. A T-statistic of 0 indicates no difference; more positive scores mean stronger fNIRS signal change with stimulation of the shoulder, compared to stimulation of the thumb point; more negative scores mean change with stimulation of the thumb, compared to the shoulder. This outcome is a number reflecting the overall magnitude of difference between stimulation points, calculated in one summary statistic. Dispersion measures cannot be calculated for the T-statistic in this analysis framework.
Time frame: 10 minutes
fNIRS response, lumbar spine vs. shoulder auricular points
Calculated T-statistic for contrast of analyzed fNIRS signal change, comparing responses from stimulation of the ipsilateral ear at the auricular points corresponding to the lumbar-spine vs. shoulder. A T-statistic of 0 indicates no difference; more positive scores mean stronger fNIRS signal change with stimulation of the lumbar point, compared to stimulation of the shoulder point; more negative scores mean change with stimulation of the shoulder, compared to the lumbar spine. This outcome is a number reflecting the overall magnitude of difference between stimulation points, calculated in one summary statistic. Dispersion measures cannot be calculated for the T-statistic in this analysis framework.
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Time frame: 10 minutes