From Projectome to Synapse
A hands-on activity explaining why BRAIN CONNECTS needs both APEX and IC3.
From Projectome to Synapse
Audience: high school through graduate / public programs
Time: 25–40 minutes
Home modules: 01, 04, 05, 11, 12, 22
Central question
If two brain regions are connected, what exactly do we know?
The answer depends on the scale of the measurement.
Build the connectivity ladder
Arrange these from broadest to finest structural description:
- Region-to-region connectivity
- Axonal projectome
- Single-cell projection
- Cell-to-cell connectivity
- Synaptic connectome
Then add two maps that answer different questions:
- Cell atlas
- Activity map
What APEX coordinates
APEX focuses on the primate axonal projectome: long-range wiring in macaque and human brains across multiple imaging modalities.
Ask learners:
- Why might diffusion MRI be useful even though it does not resolve synapses?
- Why benchmark it against optical or X-ray methods?
- Why is whole-brain coverage valuable?
- What claims become possible at projectome scale?
- Which claims remain impossible?
What IC3 coordinates
IC3 focuses on integrating cellular/synaptic, fluorescence, and barcoded connectivity resources across CONNECTS, including common pipelines and a unified knowledge representation.
Ask learners:
- Why do cell type and connectivity need a common coordinate framework?
- Why can two accurate datasets still be hard to combine?
- Why do standards and versioning matter scientifically?
- What changes when a wiring diagram can be connected to molecular cell identity?
Evidence challenge
| Claim | Minimum evidence |
|---|---|
| Area X has a long-range pathway to Area Y | region/projectome-scale connectivity |
| This molecularly defined cell class projects to Area Y | cell identity + projection map |
| Neuron A makes a synapse onto neuron B | synaptic connectivity |
| This connection is active during behavior Z | connectivity + activity |
| This connection is necessary for behavior Z | connectivity + causal perturbation |
Public communication challenge
Rewrite:
“CONNECTS is mapping every connection in the human brain.”
A defensible version:
BRAIN CONNECTS is developing complementary technologies and coordinated resources for mapping brain connectivity across multiple scales. Different projects target different levels, from long-range pathways to cellular and synaptic connections.
Exit ticket
Complete:
- A projectome is useful because __.
- A projectome cannot by itself tell me __.
- A synaptic connectome adds __.
- A synaptic connectome still cannot by itself tell me __.
- APEX and IC3 are complementary because __.