Trace circuits
Identify neurons and synapses involved in sensing, learning, recall and behavior.
Interactive educational model
What can 166,000 neurons teach us about memory loss?
Scientists have mapped the complete brain and central nervous system of an adult male fruit fly. Explore what that breakthrough contains—and the careful path from a wiring diagram to useful Alzheimer’s research.
166,000+neurons
125 millionsynapses
1 complete CNSbrain + nerve cord
Illustrated connectomenetworkmemory route
The map: a structural wiring diagram from one healthy adult male fly—not a recording of thoughts, activity or Alzheimer’s disease.
From map to medicineA powerful hypothesis engine.
01 · MAP 02 · MODEL 03 · TEST 04 · VALIDATE 05 · TRANSLATE
A powerful hypothesis engine.
Not a tiny human brain.
The connectome can help researchers choose better experiments. It cannot by itself reproduce Alzheimer’s, predict a treatment or show how a living network changes over time.
Add biology
Introduce amyloid, tau or gene changes in selected cell types in living flies.
Measure effects
Observe memory, neural function, lifespan and structural changes.
Check elsewhere
Retest promising mechanisms in human cells, organoids and mammalian models.
Inform research
Use confirmed findings to sharpen human studies—not skip the required steps.
Try the concept
Can a fly forget?
Fruit flies can learn associations between an odor and a reward or unpleasant stimulus. This simplified demonstration shows the logic of an olfactory-memory test; it does not display results from the new connectome.
A three-step memory assay
Follow how researchers train, wait and test. In a real study, control flies are compared with genetically or chemically altered groups.
Odor A
Odor B
Train: pair Odor A with a reward or aversive event.
Evidence and limits
What this can—and cannot—tell us.
What we know
- The male connectome maps more than 166,000 neurons and about 125 million synaptic connections.
- Fly and human nervous systems share many fundamental genes and cellular processes.
- Flies support rapid genetic screens and measurable learning and memory experiments.
- Connectomes can generate testable circuit-level hypotheses.
What we don’t know
- A wiring diagram does not reveal the full electrical and chemical state of a living brain.
- A fly model cannot reproduce the complexity of human Alzheimer’s disease.
- Results in flies may fail in human cells, other animals or clinical studies.
- The new map has not itself produced an Alzheimer’s treatment.
Editorial status: This page is a sourced educational explainer and has not been medically reviewed. It does not provide diagnosis, treatment advice or a claim that fruit-fly research will lead to a cure.
Read the research
Primary sources and further reading.
Sexual dimorphism in the complete connectome of the Drosophila male central nervous systemCell, 2026 · Primary connectome paper
Open paper ↗Male CNS ConnectomeHHMI Janelia · Dataset, tools, documentation and CC BY license
Explore data ↗A connectomics milestone: Mapping the complete male fruit fly brainGoogle Research · Plain-language project overview
Read overview ↗Neuronal wiring diagram of an adult brainNature, 2024 · Female fruit fly brain connectome
Open paper ↗Studies of neurodegenerative diseases using DrosophilaPeer-reviewed open-access review · Genetic screens, aging and memory assays
Read review ↗