01 December 1998

Modern interfaces for old senses

Even as Lovelace considered Mr Babbage's distaste at the interpenetrations of silicon and flesh, she read of the current work of Dr Roy Bakay of Emory University, Atlanta. This neurosurgeon's team has pioneered vitreous brain implants enabling paralysed patients to send cursor commands directly to an Analytical Engine.

Lovelace was already amazed at advances in surgery, such as two years ago when a young friend had a severed foot reattached and was walking within months. More surprising still is the recent transplant of a complete forearm onto a patient who lost his own a quarter century ago. Such miracles highlight the brain's marvellous capacity, even limited by its inability to regenerate central nervous tissue, to reconnect and reroute.

Vladimir Ulyanov (better known as Lenin) once told his followers, "If an individual dies, so do his cell and its neighbours; but the organisation remains and will talk around the wreckage". This seems a universal principle, recalling how the Internet routes around damage (or censorship). The brain too follows this logic, as we may read in Dr Oliver Sacks' wonderful accounts of the adaptations of patients in overcoming neurological disasters.

The human mind, as Babbage noted, can accept diverse and simultaneous input through its natural senses. Its very generality, however, extends to novel connections. Finding that a motor neurone cluster moves a screen cursor rather than a now-useless toe, the brain adapts to the new tool. Nor need its architecture be mapped in detail. As experience of cochlear implants shows, given a multi-electrode contact in the appropriate region, the brain rapidly learns to use the unfamiliar 'interface'.

In a world with such neural interfacing, fictional fantasies will inevitably move to everyday implementation. Futurologists at BT's Martlesham laboratories suggest that complete human 'souls' will be copied to backing store (an idea pursued by novelist Mr Greg Bear through his Eon cycle). More prosaically, and a nearer prospect, a subset of a person's expertise might be copied to control, for instance, an industrial plant.

Such machine entities, fragments of thought transplanted to electronic containers, cannot be human: but their adaptability will survive and operate in inconceivably new forms as ... something else. Perhaps they will merge or cross-fertilise with artificial software entities, or with the progeny of Rodney Brooks' robotic creations? Extraordinary vistas indeed, for minds designed for foraging in the forest margins of a tropical rift valley.