Figure 10: Showing the expressive lines of m. frontalis in a young girl 1854 - 1856

This photograph, titled "Figure 10: Showing the expressive lines of m. frontalis in a young girl," was taken by the French physician and photographer Guillaume Benjamin Amand Duchenne between 1854 and 1856. It is one of a series of images from Duchenne's book "Mécanisme de la Physionomie Humaine, ou Analyse Électrique de l'Expression des Passions," which documented the effects of electrical stimulation on human facial muscles. In this particular image, an electrode has been attached to the frontalis muscle, causing the subject's eyebrows to raise and create a surprised expression. The use of electrical stimulation and close-up portraits demonstrate Duchenne's pioneering work in the field of electrophysiology and its impact on the study of facial expressions. Duchenne's research was crucial in the development of psychology and the understanding of human emotions.