Module 12: Big Data in Connectomics

Teaching Deck

Learning Objectives

• Describe core architecture patterns for petascale connectomics data
• Plan compute, storage, and indexing strategies for large EM volumes
• Implement query workflows that preserve provenance and reproducibility
• Identify bottlenecks and failure modes in large-scale analysis pipelines

Session Outcomes

• Learners can complete the module capability target.
• Learners can produce one evidence-backed artifact.
• Learners can state one limitation or uncertainty.

Agenda (60 min)

• 0-10 min: Frame and model
• 10-35 min: Guided practice
• 35-50 min: Debrief and misconception correction
• 50-60 min: Competency check + exit ticket

Capability Target

Produce a scalable, reproducible query-and-analysis plan for a large connectomics dataset, including storage assumptions, indexing strategy, and provenance capture.

Concept Focus

1) Data architecture is scientific method infrastructure

• Technical: storage format, chunking, and indexing influence what questions are tractable.
• Plain language: bad architecture can make good science impossible.
• Misconception guardrail: compute scale alone does not solve poor data design.

Core Workflow

• See module page for details.

60-Minute Run-of-Show

• **00:00-08:00

  Architecture framing and failure examples**

• **08:00-20:00

  Access-pattern to index mapping exercise**

• **20:00-34:00

  Query profiling and bottleneck diagnosis**

• **34:00-46:00

  Provenance logging implementation**

• **46:00-56:00

  Team review of reproducibility gaps**

• **56:00-60:00

  Competency check and next-step assignment**

Misconceptions to Watch

• Misconception guardrail: compute scale alone does not solve poor data design.
• Misconception guardrail: “it runs eventually” is not acceptable for iterative science.
• Misconception guardrail: notebook history alone is insufficient provenance.

Studio Activity

Activity Output Checklist

• Evidence-linked artifact submitted.
• At least one limitation or uncertainty stated.
• Revision point captured from feedback.

Assessment Rubric

• Minimum pass
• Query design matches analysis goal and data shape.
• Provenance requirements are explicit and actionable.
• Bottlenecks are identified with one realistic mitigation.
• Strong performance
• Separates exploratory and production query paths.
• Quantifies tradeoffs (latency, cost, reproducibility).
• Anticipates failure recovery and rollback needs.
• Common failure modes
• Index choices disconnected from query workload.
• Missing version metadata in outputs.
• Optimization attempts without benchmark baseline.

Exit Ticket

Document one query you use with:

1. data source/version,
2. expected runtime class,
3. one provenance field you currently miss.

References (Instructor)

• H01 human cortical fragment release and infrastructure notes.
• MICrONS data platform documentation.
• Januszewski et al. (2018) for scalable reconstruction context.

Teaching Materials

• Module page: /modules/module12/
• Slide page: /modules/slides/module12/
• Worksheet: /assets/worksheets/module12/module12-activity.md