One way - it detects inputs of the starter neurons.

6/ As BRISC does not depend on the availability of transgenic animals, it is readily applicable across brain areas and species to systematically investigate how microcircuit organization varies across the brain and the evolutionary tree.

Preprint at www.biorxiv.org/content/10.1...

\5 Long-range inputs onto single V1 neurons reveal the topography of feedback projections from higher visual areas, which mirrors the retinotopic organisation of the visual cortex.

4/ We apply BRISC in the mouse primary visual cortex, mapping 7,814 putative synaptic connections of 385 starter neurons and identifying layer- and cell-type-specific connectivity rules.

3/ Barcodes are read out from intact tissue sections using in situ sequencing, thus reconstructing presynaptic ensembles of individual starter neurons while preserving spatial information.

2/ BRISC uses random molecular barcodes transsynaptically transmitted by rabies viruses to map inputs of many neurons simultaneously, while maintaining single cell resolution. Connections between individual neurons are then identified by matching their barcode sequences.

Wow! End of an era indeed! Once a few years ago I tried to crossreference the timing of your and BGB's tweets but there was no clear signal.

(3) We are also looking for a Doctoral Clinical Fellow to join us to map synaptic connections in human brain tissue using high throughput molecular methods, in partnership with Dimitri Kullmann at UCL:
www.crick.ac.uk/careers-stud...

(2) Joint studentship with Laura Andreae at KCL to understand mechanisms of development of corticocortical connections:
www.crick.ac.uk/careers-stud...