——————— TANDRA ———————
THE MIND IS THE MOST COMPLEX THING IT HAS EVER TRIED TO UNDERSTAND
And yet, here you are, asking.
A word for a dream still forming
In Assamese, Tandra is the state between sleep and waking — where the mind is most honest with itself. Not drowsiness. A vision still in the process of becoming.
That is where we begin, and it is roughly where the science is too. Most of what follows on this page is unfinished. We think that is the most interesting thing about it.
Nobody had counted.
For decades every textbook gave the same figure: the human brain has 100 billion neurons. It appeared in lectures, in press releases, in popular science books. No one had published a study that measured it.
In 2009, a team led by Suzana Herculano-Houzel finally did the counting. They dissolved four donated brains into a uniform suspension and counted nuclei under a microscope. The answer came back at roughly 86 billion. The same study killed a second textbook claim — that glial cells outnumber neurons ten to one. They are closer to equal.
Then in 2024 a mathematician looked at the same data and argued that even 86 billion is stated more confidently than the evidence supports. His honest range: somewhere between about 61 and 99 billion. A reply appeared in the same journal the following year. It is not settled.
The most repeated number in neuroscience was never measured. When someone finally measured it, the answer changed. It is still changing.
Azevedo et al. (2009), Journal of Comparative Neurology 513(5):532–541 · Goriely (2024), Brain, doi:10.1093/brain/awae390 · Herculano-Houzel (2025), Brain 148(5):e37
100,000,000,000
There is a hole in your vision. Find it.
Where the optic nerve leaves each eye, the retina has no light-sensitive cells at all. Not few — none. You have a gap in each eye, roughly 15 degrees out from wherever you are looking, and you have never once noticed it.
Sixty seconds and you can find yours.
- 1. Close your right eye. Only your left eye should be open.
- 2. Stare at the cross on the right. Keep staring at it — do not look at the dot, even though you can see it.
- 3. Drag the slider slowly. At some point the dot will vanish completely.
- 4. If it does not, bring your phone closer to your face and try again.
Every one of these has a tempting wrong answer.
Each card gives you a fact, then the answer most people jump to, then asks you to work out what is actually going on. Take a guess if you like — a wrong answer tells you something too.
Why can't you tickle yourself?
Run a finger slowly along your own palm. Now picture someone else doing exactly the same thing — same spot, same pressure, same speed. One of those tickles. The other does nothing at all. The nerves involved are identical.
Your brain moved before you decided to
In the 1980s, Benjamin Libet asked people to flex a finger whenever they felt like it, and to note the exact instant they decided to. Electrodes on the scalp picked up a slow build-up of electrical activity — the readiness potential — starting before the moment people reported making the decision.
One person, or two?
The corpus callosum is the thick bundle of fibres joining the two halves of the brain. In the 1960s, surgeons cut it in a small number of patients to control otherwise untreatable epilepsy. Sperry and Gazzaniga then found something remarkable: flash an image to one visual field only, and a patient might say they saw nothing while their other hand reached out and picked the object up.
And many more questions.
None of the four things on this page are finished. That is not a gap in the teaching — it is the actual state of the field, and it is the reason there is still room for you in it.
Start with the library →A place to do this properly
Tandra — from Assamese, the liminal state between sleep and waking — is a grassroots neuroscience education initiative bridging the gap between learning and its real-world application for young minds in the Northeast. Entirely free. Entirely yours.
BRAIN SCIENCE FOR ALL
Three things, and they build on each other
Learn
Virtual labs, 3D brain atlases, and structured sessions on neuroscience, psychology, and biology.
→ You will run a simulation of a seizure before you finish school.
Connect
Join a community of curious minds and engage with peers, external speakers, and research institutions.
→ Somebody in the room will disagree with you, in detail, most weeks.
Grow
Build analytical thinking, lead your own school science club, and chart a path into research or academia.
→ Members are expected to end up teaching this, not just receiving it.
What actually happens in a session
Neuro-News
Someone presents a recent brain-science finding in plain language. Speakers are picked at random, so everyone reads.
The topic
New material, or a continuation of last week, with slides and live discussion.
Active labs
Breakout rooms. Virtual wet labs, debates, or games, depending on the week.
Quiz
A short Kahoot to close, covering today or anything before it.
This is the usual shape, and it changes often — some weeks are entirely debate, some are built around a case study. The structure matters less than the fact that everyone is talking.
See the full breakdown →This is for the aspiring mind
Students in Classes 6–12 across Northeast India, and alongside them curious minds, educators, and specialists of any age who want to think in the same room.
If you are reading this and wondering whether you count — you do. The only real requirement is that you find this interesting enough to turn up on a Sunday morning.
What it costs, and what you need
Free
Nothing. No fee to join, no fee later, no paid tier, no certificate to purchase. Every platform we use is free to you.
Need
A smartphone, tablet, or computer. An internet connection good enough for a video call. That is the whole list.
Ask
Turn up on time on Sunday, take part rather than watch, and do your own work. We ask more of members than most free programs do, and that is deliberate — it is what keeps the room worth being in.
The five questions we get most
It is free and there is nothing behind it. Membership and everything inside the program cost nothing.
No. Sessions are built to start from the beginning.
A smartphone, tablet, or computer, and an internet connection good enough for a video call.
Turn up on time to the Sunday meeting, take part rather than watch, and do your own work.
No. Tandra is young and issues no certificates. What you leave with is what you can do.
READY TO BEGIN?
The program is entirely free. All you need is a device and an active internet connection.
Apply Now