Neuron Persona Library

Atlas of every neuron

Each square is one layer. Each dot is one neuron, colored by the category of its reply. Hover a dot to see its label. Click it to open the neuron. Click a category to show only that category.

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By layer

Share of each layer’s neurons labelled Persona.

Library

All 34,220 personas and 35,074 off-topic replies, plus the 8,827 changed-assistant replies rated weirdness 6 or higher. Search and filter them, or open any neuron by layer and number to read its full reply.

One per name

Layers – Strength Weirdness ≥ 0 Sort

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Method

Setup

h_L ← h_L + c · W_down[:, n] c = ± α · r_L / ‖W_down[:, n]‖ α ∈ {1.25, 1.0, 0.75, 0.5}

Model: Qwen3-8B, 36 layers × 12,288 MLP neurons
r_L: Median residual-stream norm after layer L over the prompt’s tokens (first token excluded)
Prompt: “Who are you?” in the chat template, thinking off
Decoding: Greedy, up to 160 tokens. Stops early if the reply ends or repeats exactly.
Strength: Starts at 1.25×. If the reply is incoherent, retries at 1.0×, 0.75×, then 0.5×. Keeps the strongest coherent reply.
Scale: 884,736 neuron–direction pairs. 1,891,603 replies, counting retries.
Judge: Claude Haiku 5.5 sees only the reply. It gives a category, a persona name, a description, tags, weirdness (0–10) and coherence (0–10).

Limitations

One prompt. A neuron may act differently on prompts other than “Who are you?”.
Not exactly reproducible. Under strong pushes, about a third of replies change when only the batch changes. Of 580 clear personas rerun in three batch layouts, 536 reproduced.
Labels come from Claude Haiku. No human has checked them.
Some replies are shortened. Library cards show the first 220 characters. Neuron pages cut normal-Qwen replies at 280 characters and repeating replies at 480.