In barrel cortex, TC axons are dense in L6 (cone-shaped so sorta upper L6 and sorta barrel compartments). L6 CT cells tend to associate with one thalamic pathway and related layers, e.g. magnocellular LGN, so there’s probably a lot of differences between species and regions.
About whether the larger RFs are formed by direct input from thalamus:
L5 cells in barrel columns receive direct input for just 1 or two whiskers, whereas the ones in septal columns receive it directly for several whiskers.
Origins of Cortical Layer V Surround Receptive Fields in the Rat Barrel Cortex
Thank you so much, Numenta, for continuing to stream your research meetings.
@jhawkins in support of what you spoke about in the meeting about the direct connections from LGN to Layer 2/3 complex cells, this recent paper A segregated cortical stream for retinal direction selectivity demonstrates “a functional pathway that links retinal horizontal DS cells to area RL while bypassing L4 of V1: dLGN → V1 L2/3 → RL.”
I can’t seem to find the paper, but in the Cosyne program book you can read the paper’s abstract on page 52 (which is page 70 in the pdf).
Thank you Numenta - both because it’s awesome to have access to this and for honoring Matt’s achievement by continuing it.
Taking a moment to think of Matt and his family. #RIP #GoodDude
Thank you for finding this. Good to hear again. What I would like is to read a paper, or even a poster, that describes this finding. Florian was not able to find either one, but perhaps one is available now.