{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2021:4MWCNO6FFHAQPZOC4M3BTXB5SH","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"708c568e039400570c06a439f0876a23c8353a772ee8d2734f4f21e23890a05f","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cs.NE","submitted_at":"2021-04-30T17:56:00Z","title_canon_sha256":"5768aab5a6317871347a1ba84d0186a0e6e89a83a533b50c30920db0345ee8cc"},"schema_version":"1.0","source":{"id":"2104.15137","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2104.15137","created_at":"2026-07-05T03:38:59Z"},{"alias_kind":"arxiv_version","alias_value":"2104.15137v2","created_at":"2026-07-05T03:38:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2104.15137","created_at":"2026-07-05T03:38:59Z"},{"alias_kind":"pith_short_12","alias_value":"4MWCNO6FFHAQ","created_at":"2026-07-05T03:38:59Z"},{"alias_kind":"pith_short_16","alias_value":"4MWCNO6FFHAQPZOC","created_at":"2026-07-05T03:38:59Z"},{"alias_kind":"pith_short_8","alias_value":"4MWCNO6F","created_at":"2026-07-05T03:38:59Z"}],"graph_snapshots":[{"event_id":"sha256:f8c5617f38f0b3bd5485c434a262f2a6376f16786ed25e1e56626c4204c74498","target":"graph","created_at":"2026-07-05T03:38:59Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2104.15137/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Predictive coding (PC) is a general theory of cortical function. The local, gradient-based learning rules found in one kind of PC model have recently been shown to closely approximate backpropagation. This finding suggests that this gradient-based PC model may be useful for understanding how the brain solves the credit assignment problem. The model may also be useful for developing local learning algorithms that are compatible with neuromorphic hardware. In this paper, we modify this PC model so that it better fits biological constraints, including the constraints that neurons can only have po","authors_text":"Emre Neftci, Nick Alonso","cross_cats":[],"headline":"","license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cs.NE","submitted_at":"2021-04-30T17:56:00Z","title":"Tightening the Biological Constraints on Gradient-Based Predictive Coding"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2104.15137","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:6f9836f79d3fb75986adeb23c06f6f3783176f0b7dfb725aefbc0573a4b0e25b","target":"record","created_at":"2026-07-05T03:38:59Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"708c568e039400570c06a439f0876a23c8353a772ee8d2734f4f21e23890a05f","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"cs.NE","submitted_at":"2021-04-30T17:56:00Z","title_canon_sha256":"5768aab5a6317871347a1ba84d0186a0e6e89a83a533b50c30920db0345ee8cc"},"schema_version":"1.0","source":{"id":"2104.15137","kind":"arxiv","version":2}},"canonical_sha256":"e32c26bbc529c107e5c2e33619dc3d91dfc15be74021dbe02c8c1389f18b2b65","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"e32c26bbc529c107e5c2e33619dc3d91dfc15be74021dbe02c8c1389f18b2b65","first_computed_at":"2026-07-05T03:38:59.822869Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T03:38:59.822869Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"TqW4XJEa9MjRt5MN6zzGDy7mB2ylfk93KEpJLNDDT1GAZFRCKXl7OwyTj+MxgfnIhT+f2Q7SzeBv4lNNDtoGDw==","signature_status":"signed_v1","signed_at":"2026-07-05T03:38:59.823250Z","signed_message":"canonical_sha256_bytes"},"source_id":"2104.15137","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:6f9836f79d3fb75986adeb23c06f6f3783176f0b7dfb725aefbc0573a4b0e25b","sha256:f8c5617f38f0b3bd5485c434a262f2a6376f16786ed25e1e56626c4204c74498"],"state_sha256":"ec6a0e5c1573ca01cc2fff574fb4de38f4f30110e523bcc0e56631d77ce707f0"}