📊 Data:
🧠 36 brains imaged by whole-brain LSFM (shoutout @LifeCanvasTech)
🔬 40 brains imaged with confocal
📍 Anterograde tracing from 8 isocortical areas
📍 Retrograde labeling from 4 brainstem/spinal targets

🧵 More to come—read the preprint
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(5/5)

We demonstrate how these two neurogenic programs—with distinct evolutionary histories—differentially shape isocortical output architecture, establishing it as the apex of hierarchical sensorimotor integration.
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(4/5)

This expansion is area-specific—reflecting the functional specialization of each region across motor, sensory, and associative areas.

It’s shaped by pruning of a pan-isocortex corticospinal axonal scaffold in indirect, but not direct, ET neurons.
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(3/5)

Using novel genetic access to directly- and indirectly-generated extratelencephalic (ET) neurons in the same mouse, we find:

🧠 Direct ET neurons: Project primarily to forebrain & midbrain
🧠 Indirect ET neurons: Amplify these projections and massively expand to hindbrain & spinal cord
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(2/5)