Scientists Grow 'Mini-Brain On the Move' That Can Contract Muscle

An anonymous reader quotes a report from The Guardian: Scientists have grown a miniature brain in a dish with a spinal cord and muscles attached, an advance that promises to accelerate the study of conditions such as motor neurone disease. The lentil-sized grey blob of human brain cells were seen to spontaneously send out tendril-like connections to link up with the spinal cord and muscle tissue, which was taken from a mouse. The muscles were then seen to visibly contract under the control of the so-called brain organoid. The research is is the latest in a series of increasingly sophisticated approximations of the human brain grown in the laboratory -- this time with something approaching a central nervous system attached.

The scientists used a new method to grow the miniature brain from human stem cells, which allowed the organoid to reach a more sophisticated stage of development than previous experiments. The latest blob shows similarities, in terms of the variety of neurons and their organisation, to the human foetal brain at 12-16 weeks of pregnancy. However, the scientists said the structure was still too small and primitive to have anything approaching thoughts, feelings or consciousness. While a fully developed human brain has 80-90 billion neurons, the organoid has a couple of million, placing it somewhere between a cockroach and a zebrafish in terms of volume of grey matter. After growing the organoid, the scientists 'used a tiny vibrating blade to cut it into half millimeter-thick slices which were placed on a membrane, floating on a nutrient-rich liquid,' reports The Guardian. 'This meant the entire slice had access to energy and oxygen and it continued developing and forming new connections when it was kept in culture for a year. Alongside the organoid, the scientists added in a 1mm-long spinal cord, taken from a mouse embryo, and the surrounding back muscle. The brain cells automatically began to send out neuronal connections, linked up with the spinal cord and began sending electrical impulses, which caused the muscles to twitch.'

The study has been published in the journal Nature Neuroscience.

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