Mice were then placed on a heated platform and ERGs recorded using commercially available equipment (Espion E2; Diagnosys LLC, Massachusetts USA) after corneal contact electrodes and midline subdermal reference and ground electrodes were placed.
For recording VEPs, recording electrodes (silver-silver chloride) were placed epidurally on each side 7 mm behind the bregma and 3 mm lateral of the midline, and a reference electrode was placed epidurally on the midline 12 mm behind the bregma at least 7 days before the experiments.
Electrode disks were fixed with electrolytic paste to the scalp at Cz (active), midline posterior neck (reference), and Fpz (ground).
However, a recent study exploring autonomic responses to anodal, cathodal, and sham stimulation of the frontal midline with an extracephalic reference found no significant effects of stimulation with an extra-cephalic reference (Vandermeeren, Jamart, & Ossemann, 2010).
Projective Straightening Algorithm is used to straighten the medial axis, with straighten medial axis as reference and midline, binary image is straightened.
The responses were picked up from a disc electrode placed on the midline site, Cz, with reference to an electrode placed on the ipsilateral mastoid.
Since the scalp and neck EMG magnitude is lower at electrode locations near the top and centre on the head, EMG will be lower if, instead of using an average reference, a midline channel, such as CZ, is used as a reference.
Distance of the linea alba to the peritoneum on top of the liver (PP-distance) and 2. Areas of 1 and 2 cm length along the midline, starting from the reference point in direction of the navel (PP-area-1, PP-area-2).
Distance of the inner surface of subcutaneous tissue to the linea alba (SC-distance) and 2. Areas of 1 and 2 cm length along the midline starting from the reference point in direction of the navel (SC-area-1, SC-area-2).
