Dorsal view of the skull illustrating the placement of electrodes. The EOG electrodes penetrated the connective tissue separating the orbit from the frontal bone (os frontale) bilaterally. Both electrodes were gently born around the musculus rectus lateralis without penetrating the muscle tissue. The two rostral EEG electrodes were placed centrally at the frontal bone, a third EEG electrode and one grounding electrode were placed caudally at the parietal bone (os parietale). Two EMG electrodes were inserted in neck muscles bilaterally (adapted from: www.informatics.jax.org).