An anonymous reader writes: 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 80-90bn neurons, the organoid has a couple of million, placing it somewhere between a cockroach and a zebrafish in terms of volume of grey matter.