Snails help spinal study

Snails could hold the secret behind spinal cord repair

London: Researchers have said that watching how snails pace their eating can help in the study of human behaviour, such as walking fast or using longer strides, and in the future, in the repair and control of damaged spinal cords. Studies conducted by the Mount Sinai School of Medicine in New York on Aplysia marine snails to look how nerve cells dictated movement revealed that "basic" neurons controlled the details of movements, but higher level neurons affected factors such as speed. Scientists believe that understanding how the process worked would help them study spinal injuries in a better manner. The findings appear in the journal Current Biology. Researchers said that their work had relevance in understanding repair and control within the damaged spinal cord, adding that direct clinical application was, however, a long way off. "Most systems which control movement in animals and humans are organised into a hierarchy of at least two layers of neurons. In humans, the "basic level" neurons are found in the spinal cord and the "higher level" in other areas of the nervous system, such as the brain stem. Messages from the brain tell "pattern generator" circuits of basic neurons within the spinal cord to perform the required task, intervening as necessary to ensure precise control," said John Cavanagh from the International Spinal Research Trust Scientists said that focussing on how the snails bite when they sense food is near, revealed that biting action was controlled by "basic level" neurons, but two higher-order neurons worked together to dictate how fast the snails performed the movement.

The researcher leading the study, Dr Jian Jing, told BBC that the findings could be used to help people with spinal injuries. Researchers said that they were already looking at extracting signals from the cerebral cortex - which controls functions such as movement, vision and hearing - to see if they can control prosthetic devices in patients who are paralysed because their brains are disconnected from the spinal cord. "Our work suggests that an alternative approach is to use these higher order signals to directly stimulate the spinal 'basic level' neurons in various combinations to generate a variety of behaviours. Of course, this requires more studies on how the 'basic level' neurons are organised in the spinal cord," said Dr Jing. "The study may also help robotics researchers to design more intelligent robots that utilise a hierarchical controller where elements at different levels implement different functions," he added.
Oct 17, 2005