Psychometric curves generated by a forced-choice assessment of ambiguous threat show sharpened discrimination between threat and non-threat while breathing stress-derived sweat.

<p>For each participant, data for each condition (STRESS, EXERCISE) were fitted with the sigmoid function, where <i>p</i>₀ and <i>p</i>₀+Δ<i>p</i> define upper and lower asymptotes, A₀ is the inflection point, and σ defines slope. Significant differences between conditions were seen for slope, with individuals under the STRESS condition more closely approximating ideal perceptual discrimination, shown by the dotted line.</p

Gas chromatography mass spectroscopy analyses of exercise sweat samples were used to validate that our collection and aqueous extraction methods were capable of sampling over hydrophobic (steroid) components in human apocrine sweat.

<p>Mass spectrum of retention time 20.655 minutes shows the presence of human steroids found in apocrine sweat.</p

Full-brain activation maps for replication fMRI study, showing activation levels (STRESS>EXERCISE) in warm colors and de-activations (EXERCISE>STRESS) in cool colors, showed that differences between the two conditions were most pronounced in the amygdala, with no significant de-activations.

<p>These images were produced at <i>p</i><0.005, with extent threshold = 5 voxels. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0006415#pone-0006415-t001" target="_blank">Table 1</a> provides a list of all significantly activated clusters corresponding to this whole-brain random-effects analysis.</p

Gas chromatography mass spectroscopy analyses of exercise sweat samples were used to validate that our collection and aqueous extraction methods were capable of sampling over hydrophobic (steroid) components in human apocrine sweat.

<p>Total ion count gas chromatography trace of aqueous human sweat extract shows the presence of cholesterol, which is hydrophobic.</p

Gas chromatography mass spectroscopy analyses of exercise sweat samples were used to validate that our collection and aqueous extraction methods were capable of sampling over hydrophobic (steroid) components in human apocrine sweat.

<p>Mass spectrum of retention time 19.512 minutes shows the presence of human steroids found in apocrine sweat.</p

During the fMRI scans, participants' breathing was synchronized via a continuously expanding and contracting circle (a), which cued inhalation and exhalation, respectively.

<p>Stress and exercise sweat were presented in a randomized block design, with each 20s block comprised of four inhalations-exhalations (b), timed to a five-second cycle.</p

On Likert Scales, participants rated both conditions as mild and neutral; there were no significant differences between their ratings between conditions.

<p>A separate forced-choice discrimination experiment additionally indicated that participants were unable to distinguish between the two odors. Together, these suggest that the amygdala activation seen in response to the STRESS, but not EXERCISE, sweat was due to engagement of emotional processing rather than perception of distinct odors.</p

Developing and using the Neuroimaging and Data Sharing Data Model: the NIDASH Working Group

<div>Poster submitted to the 2014 Organization for Human Brain Mapping (OHBM) conference in Hamburg, 8-12 June.</div><div><br></div