The musculotopic organisation of projections to the external cuneate nucleus (ECN) from the neck muscles splenius (SP) and biventer cervicis (BC) was examined electrophysiologically. These muscles are divided into a number of serially arranged compartments and are supplied by nerves from different cervical segments. About one-third of ECN neurons receive input from a single nerve. The majority of ECN neurons, however, receive input from more than one nerve in each muscle. ECN neurons are also limited in their ability to follow high frequency nerve stimulation and they frequently exhibit non-linear following. The connections and characteristics of ECN neurons suggest that a minority of neurons in the nucleus have the potential for the faithful transmission of afferent signals, but the majority have the potential to transform incoming patterns of muscle receptor discharge.

There seems to be little doubt that the superior colliculus of the cat plays a crucial role in head movement. The proof comes largely from a single kind of experiment in which the superior colliculus is stimulated electrically and occasionally chemically. The movements that stimulation generates have long been regarded as close to natural movement. Some believe that stimulating the tectum and protectum led to the animals executing turning movements, and gave to them the term, “visual-grasp reflex.” The experiments by Apter were on anesthetized cats. In this case, crystals of strychnine were place on the exposed superior colliculus. The application of the crystals first caused an increase in the visual evoked potential.