Fish-brained robot at Science Museum

Shelley Batts

Brain Prof Sandro Mussa-Ivaldi
Lamprey brain research could lead to improved prosthetics
Image: Prof Sandro Mussa-Ivaldi

A robot that is controlled by the brain of a fish has gone on display at the Science Museum, London, UK.

Sensors mounted on the machine send "visual" signals to the lamprey's brain which, in turn, transmits instructions to the robot's motors.

This is trespassing on nature but ... it's worth it if it leads to new knowledge and better prosthetic limbs

Prof Sandro Mussa-Ivaldi
The part of the brain used in the experiment normally keeps the lamprey upright in the water. When connected up correctly, the organ can guide the robot towards a light source.

Scientists at Northwestern University, Chicago, US, developed the system to study how human and animal brains control movement. The intention of this, and similar, research is to learn lessons that will aid the development of better artificial limbs.

Professor Sandro Mussa-Ivaldi, whose team developed the fish-machine interface, said: "This is trespassing on nature but scientists do that all the time. It's worth it if it leads to new knowledge and better prosthetic limbs."

Mussa-Ivaldi connection of the mobile robot to the lamprey brainstem is illustrated below. Signals from the optical sensors of the robot were encoded by the brain machine interface (BMI) into electrical stimulations, with the frequency of the stimulations depending on the light intensity.

These stimulations were delivered by electrodes to the right and left vestibular pathways in the lamprey brain. The stimuli are specifically delivered to the axons of the intermediate and posterior octavomotor nuclei (nOMI and nOMP), and recording electrodes record responses to the stimuli which are subsequently decoded by the BMI. During decoding, first the recording artifacts are removed, then the population spikes (bursts of activity) are detected and an average firing rate is computed. This firing rate is translated into a command to the corresponding wheel of the robot, which the angular velocity of the wheel set to be proportional to the average firing rate.

Researchers believe that in the future robotic arms and legs will be wired directly into, and controlled by, the brains of individuals whose own limbs have been lost because of accident or disease. Recent studies by Nudo and co-workers have provided preliminary evidence that the combination of behavioral training and electrical stimulation of areas surrounding a cerebrovascular accident can lead to a significant acceleration of functional recovery. If results such as these find further support, one could envisage a future scenario in which the closed-loop interaction between a patient's brain and an external device will be used to facilitate the reorganization of neural circuits that is necessary for reestablishing normal movement patterns.