- Mind uploading is theoretically possible but at least 100 years away.
- Mapping a fruit fly's brain required 7,050 slices and 21 million photographs.
- The human brain has roughly 600 times more neurons than a fruit fly brain.
When Dobromir Rahnev considers whether your mind could live inside a computer, he starts with a confession. The Georgia Tech neuroscientist studies how brains create perception. He fully expects mind uploading to become reality. He just doesn't expect to see it.
"As of today, we're nowhere close," he wrote in an answer to a question from a 15-year-old in New Delhi who wanted to know if consciousness could be transferred to a machine.
The concept sounds like science fiction. A digital copy of your brain, complete with memories and personality, living forever inside a simulation. You could eat virtual food, travel to imaginary planets, walk through walls. The only limit would be what computers could realistically model.
Key figure
86 billion
neurons in the human brain, each smaller than a pinhead, connected by trillions of synapses
Mapping a Fly Brain Took 7,050 Slices
To understand why mind uploading remains so distant, consider what counts as progress. In October 2024, an international team called FlyWire completed the first full wiring diagram of an adult fruit fly brain.
The project required slicing a poppy-seed-sized brain into 7,050 layers and taking 21 million photographs. The resulting map captured 139,255 neurons and over 50 million connections between them.
That's the largest complete brain map ever made for any adult animal.
The human brain has roughly 600 times more neurons. Trillions more connections. And each neuron constantly adjusts its functioning based on experience, learning, and countless other factors that scientists can barely track.
What is a connectome?
A connectome is a complete map of neural connections in a brain, showing every neuron and every synapse where signals pass between them. Think of it as a wiring diagram for a mind. Scientists need this map to understand how thoughts and behaviors emerge from biological circuits.
Will it ever be possible to upload your mind and create a digital twin of yourself? Maybe. (Science Reader)
The Sensory Problem Mind Uploading Must Solve
Even if scientists could somehow scan and replicate 86 billion neurons, the uploaded mind would face another challenge. It would need sensory input.
A brain without sight, sound, touch, and internal body signals doesn't function normally. Sensory deprivation is classified as a form of torture. People who struggle to sense hunger, pain, or thirst often develop mental health problems.
A digital mind would require simulated senses accurate enough to maintain sanity.
Minor distortions could cause serious psychological harm.
Scientists don't yet understand how collections of neurons create thoughts.
Rahnev points to a deeper problem. Scientists don't yet understand how collections of neurons create thoughts. They can photograph the city, as he puts it, but they don't grasp how the buildings, streets, and infrastructure work together.
Billionaires Aren't Waiting for Certainty
Despite the obstacles, funding won't be a problem. Wealthy individuals already pour money into longevity research, including mind uploading concepts.
Some optimistic forecasts predict digital immortality by 2045.
Others suggest the end of this century.
Rahnev finds both timelines unrealistic.
"I would be shocked if mind uploading works in the next 100 years," he wrote. "But it might happen in 200."
That timeline raises an intriguing possibility. The first person to achieve digital immortality may not yet be born. But they might be born within our lifetime.
Sources
- Primary Source: Can You Upload a Human Mind Into a Computer? A Neuroscientist Ponders What's Possible (Georgia Tech Research)
- Additional Context:
- Mapping an entire (fly) brain (Princeton University)
- Complete wiring map of an adult fruit fly brain (NIH)
Fact Check: Claim-by-Claim Verification Verified
The article accurately represents Dobromir Rahnev's published position on mind uploading and correctly reports the FlyWire connectome findings.
Commentary
- The article states "over 50 million connections" while sources report more precisely 50 million or 54.5 million synapses—this simplified framing is acceptable for popular science
- The article correctly hedges speculative claims with language like "expects," "might happen," and "the only limit would be" rather than presenting mind uploading as inevitable
- Rahnev's quote about not understanding how neurons create thoughts accurately reflects the current state of neuroscience research
- The comparison that "the human brain has roughly 600 times more neurons" is mathematically sound (86 billion ÷ 139,255 ≈ 617x)
Sources used for verification
Academic/Peer-reviewed:
- Can You Upload a Human Mind Into a Computer? A Neuroscientist Ponders What's Possible - gatech.edu
- Neuronal wiring diagram of an adult brain - Nature
- The Human Brain in Numbers: A Linearly Scaled-up Primate Brain - PMC/NIH
Other reliable sources:
- Mapping an entire (fly) brain: A step toward understanding diseases and the human brain - princeton.edu
- Complete wiring map of an adult fruit fly brain - nih.gov
- Scientists have traced all 54.5 million connections in a fruit fly's brain - sciencenews.org
- Researchers Create First Adult Fruit Fly Brain Connectome - brainfacts.org
Fact-checked by Perplexity Sonar Pro on 2026-01-19
