---
id: "1943-12-01-mcculloch-pitts-neuron"
url: "https://postcutoff.com/e/1943-12-01-mcculloch-pitts-neuron/"
as_of: "2026-11-13T13:49:00+01:00"
date: "1943-12-01"
date_precision: month
category: research
importance: 5
confidence: high
status: [Confirmed]
sources: 2
editor: human editor
human_review: null
version: "2026-10-04"
---

As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/e/1943-12-01-mcculloch-pitts-neuron/

# McCulloch & Pitts publish the first mathematical model of a neural network

Warren McCulloch and Walter Pitts showed that networks of simplified binary 'neurons' can compute logical functions, founding the idea of artificial neural networks.

## Key facts
- Paper: 'A Logical Calculus of the Ideas Immanent in Nervous Activity'
- Published in the Bulletin of Mathematical Biophysics, vol. 5 (1943)
- Neurons modeled as threshold units with all-or-none output
- Showed nets of such units can implement any logical proposition

## What happened

McCulloch (a neurophysiologist) and Pitts (a logician) proposed a formal model of the neuron as a threshold logic unit and proved that networks of these units can represent logical expressions.

## Why it matters

It is the conceptual ancestor of every neural network used today, linking brain science, logic and computation.

## Your AI and this story

- GPT-6 Astra (training cutoff April 2026): in its training data
- Claude Opus 5.5 (training cutoff June 2026): in its training data
- Gemini 4 Hydrogen (training cutoff March 2026): in its training data
- Grok 4.7 (training cutoff May 2026): in its training data

## Sources

1. [A Logical Calculus of the Ideas Immanent in Nervous Activity (DOI)](https://doi.org/10.1007/BF02478259) (doi.org, paper)
2. [Wikipedia: Artificial neuron](https://en.wikipedia.org/wiki/Artificial_neuron) (en.wikipedia.org, discussion)

## Changes

- 2026-09-29 (filed): Created

## Related

- 1958-07-01: [Frank Rosenblatt's Perceptron, the first trainable neural network](https://postcutoff.com/e/1958-07-01-perceptron/index.md)