bioRxiv preprint doi: https://doi.org/10.1101/566588; this version posted March 5, 2019. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Contribution of Apical and Basal Dendrites of L2/3 Pyramidal Neurons to Orientation Encoding in Mouse V1 Jiyoung Park1,4*†, Athanasia Papoutsi3†, Ryan T. Ash2,4, Miguel A. Marin2, Panayiota Poirazi3* & Stelios M. Smirnakis4* 1Program in Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 2Department of Neuroscience, Baylor College of Medicine, Houston, Texas 3Institute of Molecular Biology and Biotechnology (IMBB), Foundation of Research and Technology Hellas (FORTH), Vassilika Vouton, Heraklion, Crete, Greece 4Brigham and Women’s Hospital and Jamaica Plain VA Hospital, Harvard Medical School, Boston, MA †Equal contribution. * Correspondence:
[email protected],
[email protected],
[email protected] Abstract: Pyramidal neurons integrate synaptic inputs from basal and apical dendrites to generate stimulus-specific responses. It has been proposed that feed-forward inputs to basal dendrites drive a neuron’s stimulus preference, while feedback inputs to apical dendrites sharpen selectivity. However, how a neuron’s dendritic domains relate to its functional selectivity has not been demonstrated experimentally. We performed 2-photon dendritic micro-dissection on layer- 2/3 pyramidal neurons in mouse primary visual cortex. We found that removing the apical dendritic tuft did not alter orientation-tuning. Furthermore, orientation-tuning curves were remarkably robust to the removal of basal dendrites: ablation of 2-3 basal dendrites was needed to cause a small shift in orientation preference, without significantly altering tuning width.