The Mammalian Brain is incredibly dynamic, flexible, and adaptable. When a micro stimulator and geomagnetic compass is attached to the brain of blind rats, they learn to use new information about their location and were able to find the way through a maze nearly as well as normally sighted rats.
The study reaffirms the belief that the mammalian brain is incredibly flexible and at the same time such neuroprosthesis could help blind people walk freely through the world.
The researchers were trying to restore the blind rat’s allocentric sense instead of vision. Allocentric sense could be described as the awareness which enables animals and people to recognize the position of their body within the environment. The researchers were trying to find answers to the question -If the animals could perceive a geomagnetic signal can it compensate for the animal’s lost sight and can the animal use this information?
The researchers created a head-mountable geomagnetic sensor device which enabled them to connect a digital compass to two tungsten micro-electrodes for stimulating the visual cortex of the brain. The device was very light weight and allowed the researchers to stimulate the brain up or down with a rechargeable battery. Once the sensor is attached, it automatically detects the animal’s head direction and generated electrical stimulation pulses indicating which direction they were facing-North or South
The blind rats were then trained to locate food pellets in a T shaped or a more complex maze. After about ten trials, the blind rats learned to use the geomagnetic information to solve the mazes. The blind rat’s performance levels and navigation strategies were similar to those of normally sighted rats. The animals’ allocentric sense was restored.
The finding could open doors for the visually impaired persons to have a better quality of life. By a simple application-attaching a geomagnetic sensors to the canes used by blind people to get around, the researchers hope to give them an allocentric sense just like the blind rats. The sensors could broaden to include ultraviolet radiation, ultrasound waves, and more. Mammalian brains, it appears, are capable of much more than our limited senses allow.
The above research has been pioneered by Hiroaki Norimoto and Yuji Ikegaya, researchers from the University of Tokyo.
Ikegaya says: “The most remarkable point of this paper is to show the potential, or the latent ability, of the brain. That is, we demonstrated that the mammalian brain is flexible even in adulthood – enough to adaptively incorporate a novel, never-experienced, non-inherent modality into the pre-existing information sources.”
Yuji Ikegaya of the University of Tokyo in Japan, head of the group that installed and tested the two five-gram implant said, “I am dreaming that humans can expand their senses by way of artificial sensors for geomagnetism, ultraviolet, radio waves, ultrasonic waves and so on. Ultrasonic and radio-wave sensors might allow the next generation of human-to-human communication.”
The details of this study have been published in the journal Current Biology under the title “Visual Cortical Prosthesis with a Geomagnetic Compass Restores Spatial Navigation in Blind Rats”