According to polarity convention, an eye movement to the right should result in which pen deflection across the electrodes?

In the context of polarity convention for electrooculography (EOG), the way eye movements are recorded relates to the positioning of the electrodes placed around the eyes. When an individual looks to the right, the electrical potential changes in the eye shift towards the electrodes used for measuring the EOG.

In this setup, if the left eye (E1) is considered as the electrode measuring the left side (the more negative potential when the eye moves right) and the right eye (E2) measuring the right side (the more positive potential during this movement), an eye movement to the right results in the E2 channel (the right eye) capturing a more positive potential, thus showing an upward deflection on the recording. Conversely, the E1 channel, being more negative as the left eye moves away from the positive potential, would show a downward deflection.

Thus, option D accurately reflects this convention, where the E2 channel demonstrates an upward pen deflection due to the positive shift when the right eye moves toward it, and the E1 channel shows a downward pen deflection because of the negative shift as the left eye moves away from it. This understanding of electrode placement and potential shifts is crucial for interpreting EOG recordings correctly.