VisualNeuroscience.AI

Microanatomy

the brain at the microscope’s scale

The atlas pages draw the brain a region at a time. This one goes down to the cell, and below that to the molecules that pass between cells and the receptors they land on. Each drawing is an original schematic built from code, with every structure a click target: pick one and read what it does, colour them all to see how the cell is put together, or switch to Test yourself and find each one from memory. One is drawn so far: a large multipolar neuron, the commonest kind in the brain and spinal cord, with the axons that reach it, an astrocyte, two labelled synapses, and its own axon leaving under a myelin sheath. The cortex’s own cell, the pyramidal neuron, is next.

Cells one drawn, more to follow

Multipolar neuron

A schematic, not to scale: the organelles are drawn larger and far fewer than in a real cell, and the axon runs on well past the edge of the frame. Click any part of the drawing to find out what it is.

Neurotransmitters the messengers, drawn

Seventeen molecules drawn as skeletal formulas, in seven groups, each with what it does — and a row of transmitters to look at one alone. Open the section

What crosses the synapse. Each is drawn as a skeletal formula: every corner and line-end a carbon, hydrogens on carbon left out, the other elements named. Most are small, a single amino acid or something made from one in a step or two, which is why the brain can make, release and clear them in milliseconds. Pick a transmitter to see it on its own — the monoamines first, since they are what most drugs act on — and open What it does under any of them.

Receptors and channels what the messengers land on

A hundred and fifty receptors, channels and transporters as ten kinds of machine, every part explaining its step on a hover — with a transmitter filter and a search box. Open the section

A transmitter does nothing until something binds it. Here is what does: the receptors for the molecules above, with the ion channels and transporters that work alongside them, a hundred and fifty in all. There are only ten kinds of machine among them, drawn first, and the first thing to know is that they come in two speeds. An receptor is a channel: the transmitter opens it in under a millisecond and it shuts as soon as the transmitter leaves. A receptor has no pore; it works through a G protein and chemical messengers inside the cell, so it is slower to act and keeps acting for seconds or minutes after the transmitter has gone. Most transmitters have both kinds, and most drugs that act on the brain act on one of the machines below. Pick a transmitter below to see only its receptors — the monoamines first, since they are what most drugs act on — and search inside it by name, drug or effect. Every word in a tile’s small capitals, and , , and here, opens a plain explanation on a hover or a tap. Each tile gives the code chemists use with the plain name under it, what binds it and how tightly, the drugs people have heard of that act on it, what happens when it is bound, and under What the kind means the kind’s explanation again with a line of context.

Each drawing is an original schematic generated from code rather than traced from a micrograph, so it owes nothing to any published plate. The descriptions are standard textbook anatomy and do not yet carry citations; the digital textbook is where each claim gets its paper. About · Privacy & support. The molecules are drawn from their chemical structures by RDKit, an open-source toolkit, and coloured by the page.