Version history
1 version on record. Newest first; the live version sits at the top with a live indicator.
- Live5/17/2026, 4:35:28 PM
081703609e54Content snapshot
{ "kind": "infographic", "prompt": "The IT/PT/CT taxonomy of mouse cortical excitatory projection neurons recurs across methodologically independent approaches — Cre-line + retrograde + electrophysiology, BARseq projection mapping, and CRACM paired recordings — but within-class heterogeneity (e.g., L6 IT vs L5B IT in CT-target specificity; Fezf2+ further split into PT-PN and IT-PN) means the same three-class label hides fine-scale subclasses that the chosen method resolves.", "provider": "other", "raw_fields": { "papers": [ { "n": null, "doi": "10.1002/cne.23875", "value": "two subtypes: PT-PNs and IT-PNs", "method": "whole-cell patch + cluster analysis + retrograde tracing", "metric": "Number of L5 Fezf2+ subtypes identified electrophysiologically", "n_analyzed": null, "ci_or_error": null, "text_access": "abstract_only", "n_definition": "patched Fezf2-GFP+ L5 neurons in M1", "scope_region": "specific region (M1)", "study_system": "mouse motor cortex L5, Fezf2-Gfp reporter", "taxonomic_level": "fine type (Cre/reporter line × projection target)", "scope_population": "subtype-Y only (Fezf2+ L5)", "value_source_sentence": "Functional electrophysiology identified two distinct subtypes of Fezf2(+) neurons that resembled pyramidal tract projection neurons (PT-PNs) and intratelencephalic projection neurons (IT-PNs).", "experimental_conditions": "in vitro slice, whole-cell patch + retrograde labeling" }, { "n": 3579, "doi": "10.1016/j.cell.2019.09.023", "value": "three top classes (IT, PT-like, CT) with laminar organization confirmed; additional projection type restricted to a transcriptomic IT subtype", "method": "BARseq (RNA-barcoded projection mapping)", "metric": "Projection classes confirmed in mouse auditory cortex via BARseq", "n_analyzed": 3579, "ci_or_error": null, "text_access": "abstract_only", "n_definition": "barcoded individual neurons with mapped projections", "scope_region": "specific region (auditory cortex)", "study_system": "mouse auditory cortex, BARseq", "taxonomic_level": "broad category (IT/PT/CT)", "scope_population": "all category-X (excitatory projection neurons)", "value_source_sentence": "Mapping the projections to 11 areas of 3,579 neurons in mouse auditory cortex using BARseq confirmed the laminar organization of the three top classes (intratelencephalic [IT], pyramidal tract-like [PT-like], and corticothalamic [CT]) of projection neurons.", "experimental_conditions": "in situ sequencing of projection barcodes" }, { "n": null, "doi": "10.7554/eLife.97602", "value": "L2/3 IT (Rasgrf2-dCre), L4 IT (Scnn1a-Cre), L5 IT, L5 PT, and L6 CT subclasses separately resolved", "method": "light-sheet axon imaging + CNN-based segmentation", "metric": "L5 projection sub-classes labeled by class-selective Cre lines", "n_analyzed": null, "ci_or_error": null, "text_access": "abstract_only", "n_definition": "axon-density quantification within CCF", "scope_region": "specific region (whisker-related somatosensory cortex)", "study_system": "mouse whisker-related S1/S2, multiple Cre lines", "taxonomic_level": "fine type (Cre-line × projection class)", "scope_population": "all category-X (excitatory projection neurons)", "value_source_sentence": "Axonal density was analyzed for different classes of glutamatergic neurons using transgenic mouse lines selectively expressing Cre recombinase in layer 2/3 intratelencephalic projection neurons (Rasgrf2-dCre), layer 4 intratelencephalic projection neurons (Scnn1a-Cre), layer 5 intratelencephalic projection neurons (Tlx3-Cre), layer 5 pyramidal tract projection neurons (Sim1-Cre), layer 5 projection neurons (Rbp4-Cre), and layer 6 corticothalamic neurons (Ntsr1-Cre).", "experimental_conditions": "Cre-dependent fluorescent labeling, light-sheet imaging, CCF registration" }, { "n": null, "doi": "10.1523/JNEUROSCI.4023-14.2015", "value": "strong CT↔CT and CT↔IT (L6 IT only); strikingly little CT↔PT excitatory connectivity", "method": "CRACM + paired recording", "metric": "Excitatory connectivity among IT/PT/CT classes in mouse M1", "n_analyzed": null, "ci_or_error": null, "text_access": "abstract_only", "n_definition": "paired recordings + CRACM-defined inputs", "scope_region": "specific region (forelimb M1)", "study_system": "mouse forelimb M1, CT/IT/PT projection-defined neurons", "taxonomic_level": "broad category (IT/PT/CT)", "scope_population": "all category-X (projection-defined excitatory)", "value_source_sentence": "Stimulating and recording from CT, intratelencephalic (IT), and pyramidal tract (PT) projection neurons, we found strong CT↔ CT and CT↔ IT connections; however, CT→IT connections were limited to IT neurons in layer 6, not 5B. There was strikingly little CT↔ PT excitatory connectivity.", "experimental_conditions": "in vitro slice with Cre/retrograde targeting" } ], "audit_issues": [ { "dimension": "scope_region", "description": "Papers cover M1, mouse auditory cortex, whisker-related S1/S2 and forelimb M1; the IT/PT/CT framework is compared across regions rather than within one.", "entries_affected": [ "10.1002/cne.23875", "10.1016/j.cell.2019.09.023", "10.7554/eLife.97602", "10.1523/JNEUROSCI.4023-14.2015" ] }, { "dimension": "taxonomic_level", "description": "Resolution differs: 'two Fezf2+ subtypes' (slice patch + clustering), 'three top classes' (BARseq), multiple Cre-line subclasses (light-sheet), and broad IT/PT/CT categories (paired patch). Counts of subtypes cannot be plotted as a single ordinal scale.", "entries_affected": [ "10.1002/cne.23875", "10.1016/j.cell.2019.09.023", "10.7554/eLife.97602", "10.1523/JNEUROSCI.4023-14.2015" ] }, { "dimension": "metric_definition", "description": "Metrics are 'number of subtypes identified,' 'projection classes confirmed,' 'sub-classes labelled by Cre lines,' and 'qualitative excitatory-connectivity pattern' — they are not the same quantity.", "entries_affected": [ "10.1002/cne.23875", "10.1016/j.cell.2019.09.023", "10.7554/eLife.97602", "10.1523/JNEUROSCI.4023-14.2015" ] } ], "audit_verdict": "CAVEAT", "comparison_id": "l5-projection-class-taxonomy-mouse", "comparison_name": "Concordance of mouse L5 IT/PT projection-class taxonomy across genetic/transcriptomic vs paired-recording methods", "comparison_type": "convergent evidence", "what_it_reveals": "The IT/PT/CT taxonomy of mouse cortical excitatory projection neurons recurs across methodologically independent approaches — Cre-line + retrograde + electrophysiology, BARseq projection mapping, and CRACM paired recordings — but within-class heterogeneity (e.g., L6 IT vs L5B IT in CT-target specificity; Fezf2+ further split into PT-PN and IT-PN) means the same three-class label hides fine-scale subclasses that the chosen method resolves.", "homogeneity_check": { "caveats": [ "Cortical areas differ across rows (M1 motor, auditory, whisker-S1/S2) — the comparison is cross-area to show the IT/PT/CT framework recurs across regions.", "Taxonomic resolution differs: BARseq and Fezf2 paper resolve subclasses, while the motor-cortex paired-recording paper uses broad IT/PT/CT categories." ], "n_definition_uniform": "false", "scope_region_uniform": "false", "taxonomic_level_uniform": "false", "scope_population_uniform": "true" }, "suggested_plot_type": "grouped bar", "mandatory_caption_caveats": [ "Rows span four cortical areas (M1, auditory, whisker-S1/S2, forelimb M1); the IT/PT/CT framework is compared across regions, not within one.", "Taxonomic resolution differs across rows (broad IT/PT/CT vs. Cre-line- or transcriptomic-defined subclasses); subtype counts are not directly comparable." ] }, "section_id": "section_02", "source_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewRecurrence/blob/79ce062d54a924ce05953ec90aa9d26044d2b48f/evidence/section_02_evidence_package.json", "target_ref": "wiki_page:computationalreviewrecurrence-02-anatomy-primer", "review_repo": "ComputationalReviewRecurrence", "section_ref": "wiki_page:computationalreviewrecurrence-02-anatomy-primer", "source_path": "evidence/section_02_evidence_package.json", "source_refs": [ "paper:paper-04affa4a6e03", "paper:paper-1bafe87bf289", "paper:paper-77ff3f69a352", "paper:paper-89006181f9d5" ], "section_title": "2. Mouse-cortex anatomy primer — areal map, layer structure, projection-class nomenclature (IT / PT / CT), tools available for E→E dissection (paired patch, Cre lines, two-photon-targeted patch, optogenetics, EM reconstruction)", "source_policy": { "mode": "public_source_pointer_with_short_context", "notes": [ "Local review repositories are read-only inputs.", "SciDEX stores paper metadata, structured evidence, file pointers, and short citation contexts; it does not copy full review prose." ], "source_commit_sha": "79ce062d54a924ce05953ec90aa9d26044d2b48f", "source_repository_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewRecurrence" }, "generation_status": "complete", "review_bundle_ref": "analysis_bundle:ab-d9c479db9be9", "origin_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewRecurrence/blob/79ce062d54a924ce05953ec90aa9d26044d2b48f/evidence/section_02_evidence_package.json", "commit_sha": "79ce062d54a924ce05953ec90aa9d26044d2b48f", "created_by": "persona-jerome-lecoq-gbo-neuroscience", "repository_url": "https://github.com/AllenNeuralDynamics/ComputationalReviewRecurrence" }