THE term ‘hypnosis’ was coined by the Scottish physician James Braid in his 1853 book Neurypnology. Braid defined hypnosis as “a peculiar condition of the nervous system, induced by a fixed and abstracted attention of the mental and visual eye”. He argued that it was a form of “nervous sleep”, and tried to distinguish his theory from that of the mesmerists, who believed that the effects of hypnosis were mediated by a vital force, or animal magnetism.
Because of mesmerism, and its association with stage entertainment and charlatanry, hypnosis was regarded with skepticism for much of its history. In recent years, though, it has come under the scrutiny of cognitive neuroscientists, and is now thought of as an altered state of consciousness – sometimes referred to as being trance-like – which is associated with increased suggestibility, enhanced imagery and reduced reality testing. We know that hypnosis can profoundly affect the mind and behaviour, so that thought processes and perceptions can be easily manipulated, but the underlying neural mechanisms are poorly understood.
According to a new study of the neural mechanisms of hypnosis-induced paralysis, Braid’s definition was remarkably accurate. The study, published in the journal Neuron, demonstrates that hypnosis does indeed lead to increased activity in areas of the brain involved in attention, as well as in other areas involved in mental imagery and self-awareness. It can therefore exert control over bodily movements by enhancing mental representations of the self (or self-imagery) and focusing attention on them.