Location: Seminar Room 4, Ground Floor - Institute of Psychiatry, Psychology and Neuroscience, 16 De Crespigny Park, London SE5 8AF.
As a medical student, Giuseppe Moruzzi was introduced to neurophysiology by Mario Camis, who had worked with Luciani in Rome and with Sherrington in Liverpool. Moruzzi owes his scientific fame mostly to his discovery with Magoun of the arousing function of the brainstem reticular formation. However he made other important contributions by proposing an active induction of sleep by the caudal brainstem and by conceiving of the so-called ARAS, the ascending reticular arousal system, as an ensemble of different interacting components. More than 50 years ago Moruzzi and his collaborators reported that cats with a complete transection of the pons in front of the origin of the trigeminal nerve were almost continuously awake, suggesting that the brain had been separated by sleep-inducing structures in the brainstem behind the section. Several pieces of experimental evidence were subsequently obtained to show that the isolated brain of midpontine pretrigeminal cats was capable of conscious awareness, learning and sensitivity to rewarding brain stimulation. The current interest of those data for clinical neurology is that there are striking resemblances between the midpontine pretrigeminal preparation and the human locked-in syndrome, in which the patients are fully conscious but unable to move except for palpebral or ocular movements. Here I present the basic evidence for assuming that the midpontine pretrigeminal cat may serve as an at least partial model for the locked-in syndrome and suggest that it may provide useful insights into the neural mechanisms of consciousness in absence of behavior.