You may find estimates in many neurobiology text books. But has anybody really counted them?
Not really. Estimates are estimates.
But now there is a technique to actually count the number of connections. There is a paper in a recent issue of Nature, that spells out a technique. Whole brain fluorescence-based axonal tracing and high throughput DNA sequencing of genetically barcoded neurons.
The scientists, some of them with unpronounceable names, have delineated the projection patterns of 591 individual neurons in the mouse primary visual cortex using the technique.
Nature 556: 51–56 (05 April 2018), doi:10.1038/nature26159
Some time ago, when I saw a paper that achieved single cell RNA sequencing to come to the conclusion that there are 11 distinct neuronal populations in the dorsal root of the spinal chord, I knew something like this is bound to happen.
Like the Genome project, this is going to throw up such large amounts of data that it will keep the computer programmers busy for some time. And it will take even more time to make some reasonable sense of the data. But this is indeed, a historical beginning. It is even more exciting than the earlier techniques that gave this image by removing all the fats from the brain leaving a protein skeleton:
Not really. Estimates are estimates.
But now there is a technique to actually count the number of connections. There is a paper in a recent issue of Nature, that spells out a technique. Whole brain fluorescence-based axonal tracing and high throughput DNA sequencing of genetically barcoded neurons.
The scientists, some of them with unpronounceable names, have delineated the projection patterns of 591 individual neurons in the mouse primary visual cortex using the technique.
Nature 556: 51–56 (05 April 2018), doi:10.1038/nature26159
Some time ago, when I saw a paper that achieved single cell RNA sequencing to come to the conclusion that there are 11 distinct neuronal populations in the dorsal root of the spinal chord, I knew something like this is bound to happen.
Like the Genome project, this is going to throw up such large amounts of data that it will keep the computer programmers busy for some time. And it will take even more time to make some reasonable sense of the data. But this is indeed, a historical beginning. It is even more exciting than the earlier techniques that gave this image by removing all the fats from the brain leaving a protein skeleton:
Image by Thomas Schultz
