Pipeline Overview

Tracer team focus
Upstream / completed

Stage 1 Sample Preparation

Biological tissue is prepared for electron microscopy imaging through fixation, staining, and embedding.

Inputs

  • Fresh tissue sample
  • Fixation protocols

Outputs

  • Resin-embedded tissue block
  • Serial ultrathin sections

Methods

Chemical fixation Heavy metal staining Resin embedding Ultramicrotomy

Stage 2 EM Imaging

Serial section electron microscopy captures high-resolution images of the tissue volume.

Inputs

  • Serial tissue sections
  • Imaging parameters

Outputs

  • Raw EM image tiles
  • Imaging metadata

Methods

Serial section TEM SEM (ATUM) FIB-SEM

Stage 3 Image Processing

Raw images are stitched, aligned, and corrected to create a contiguous 3D volume.

Inputs

  • Raw EM image tiles
  • Section ordering

Outputs

  • Aligned image volume
  • Multi-resolution pyramid

Methods

Tile stitching Section alignment Artifact correction Intensity normalization

Stage 4 Segmentation

Machine learning models identify and label individual neurons and cellular structures in the volume.

Inputs

  • Aligned EM volume
  • Training data

Outputs

  • Supervoxel segmentation
  • Initial neuron IDs
  • Merge/split predictions

Methods

Flood-filling networks Affinity prediction Agglomeration

Stage 5 Proofreading

Human annotators correct segmentation errors—splits and mergers—to produce accurate neuron reconstructions. Primary tracer team activity.

Inputs

  • AI segmentation
  • EM imagery
  • Error predictions

Outputs

  • Corrected neuron segments
  • Validated root IDs
  • Proofread status flags

Tools

WebKnossos Neuroglancer SAM2 (AI assist)

Stage 7 Analysis

Connectivity data is queried, analyzed, and visualized to understand neural circuits.

Inputs

  • Synapse tables
  • Neuron IDs
  • Cell type annotations

Outputs

  • Connectivity matrices
  • Circuit diagrams
  • Statistical summaries

Tools

tracer_tools CAVE API Python / pandas Jupyter

Stage 8 Publication

Findings are documented and shared through papers, preprints, and public data releases.

Inputs

  • Analysis results
  • Figures and visualizations
  • Methods documentation

Outputs

  • Peer-reviewed papers
  • Preprints
  • Public datasets

Pipeline Tools

Tool Stage Purpose
WebKnossos 5, 6 Volume annotation, proofreading, segmentation correction
Neuroglancer 5, 6 3D visualization, synapse annotation, data viewing
CAVE 6, 7 Annotation database, versioned data queries
tracer_tools 7 Python API for CAVE queries, batch processing, ID management
Tampermonkey 5, 6 Browser scripts for WebKnossos workflow enhancement

Supported Datasets

Dataset Organism Datastack Status
FlyWire FAFB Drosophila (whole brain) flywire_fafb_production Active
BANC Drosophila (brain + nerve cord) brain_and_nerve_cord Active