Nov 21, 2018
The Mini brains grown in a dish have produced human-like brain waves. They are the electrical patterns look similar to those of premature babies. This would aid scientists to study early brain development.
The research in this area has been sluggish, partly because it is difficult to obtain fetal-tissue samples for analysis and nearly impossible to examine a fetus in utero. Many researchers are intrigued about the promise of these ‘organoids’, if they are grown as 3D cultures, can develop into some of the complex structures that are seen in brains. But the technology also raises eyebrows regarding the ethics of creating miniature organs that could develop consciousness.
A team of researchers led by neuroscientist Alysson Muotri of the University of California, San Diego, taken human stem cells to form tissue from the cortex, a brain region that controls cognition and interprets sensory information. They grew a plethora of brain organoids in culture for 10 months and tested individual cells to confirm the expression of the same collection of genes seen in typical developing human brains. The group presented the work at the Society for Neuroscience meeting in San Diego.
Surprising patterns
Muotri and his colleagues unceasingly recorded electrical patterns, or electroencephalogram (EEG) activity, across the surface of the mini brains. By half of a year, the organoids were firing at a higher rate than other brain organoids previously created, which astonished the team.
The EEG patterns were also unanticipated. In mature brains, neurons form synchronized networks that fire with predictable rhythms. But the organoids displayed irregular EEG patterns that resembled the chaotic bursts of synchronized electrical activity seen in developing brains. When the comparison of these rhythms to the EEGs of premature babies held, they realised that the organoids’ patterns mimicked those of infants born at 25–39 weeks post-conception.
Although the organoids aren’t close to being real human brains, as quoted by Muotri. They don’t contain all the cell types found in the cortex and they don’t connect to other brain regions. The researchers plan to explore whether these structures function as a normal cortex by hooking them up to organoids that mimic other parts of the brain or body.
Brain-wave comparison
Although the work is at its initial stage, the similarities to preterm infant EEG patterns show that the organoids could eventually be useful for studying brain-development disorders like epilepsy or autism.
Origins of consciousness
The project raises eyebrows on ethical questions about whether organoids could develop consciousness. To this, the reply was that it could be difficult to know when an organoid is conscious since researchers don’t know how to measure consciousness in adults, or on when it appears in infants. Muotri apprised that halting of the project will be considered in case if there were evidence that the organoids had become self-aware.
