Robotic Brain Universe

02 · The folded sheet

A sheet of grey matter, folded

The cerebral cortex is a thin, folded sheet of grey matter: its ridges are gyri and its grooves are sulci. FreeSurfer, the software that built this template, can inflate the surface. The folds smooth out, the cortex hidden inside the sulci comes into view, and the shading keeps the pattern: light for gyri, dark for sulci.

Sources: Fischl et al. 1999; Fischl 2012

03 · Named regions

Every region has a name

Atlases divide the cortex into labelled regions, each drawn by a different method. Keep scrolling to move through three of them on the same brain: the Desikan–Killiany atlas (34 gyral regions per hemisphere), the Destrieux atlas (74 gyri and sulci per hemisphere) and 12 Brodmann areas, cell-structure maps from post-mortem brains, predicted on the template from its folding pattern.

Sources: Desikan et al. 2006; Destrieux et al. 2010; Fischl et al. 2008

04 · Beneath the cortex

The structures inside

Fade the cortex and the deep structures appear: the thalamus; the caudate, putamen and pallidum of the basal ganglia; the hippocampus and amygdala; the fluid-filled ventricles; the brainstem and the cerebellum. They come from FreeSurfer’s automated segmentation of the template brain (36 labels).

Sources: Fischl et al. 2002

05 · Connections

White-matter highways

Long bundles of nerve fibres connect distant regions. These streamlines come from a population-averaged tractography atlas built from the scans of 1,065 young adults in the Human Connectome Project. Colour shows the local fibre direction: red runs left to right, green front to back and blue up and down.

Sources: Yeh 2022; Yeh 2022 (brain.labsolver.org); Pajevic and Pierpaoli 1999

06 · Imaging

Slice through an MRI

Keep scrolling to move an axial plane up through the brain. The cut face shows the ICBM 2009a T1-weighted template at 1 mm resolution, an unbiased nonlinear average of the MNI152 database of adult scans, in the same coordinate space as the tracts. It is viewed from above in the neurological convention, with the patient’s left on screen left; the viewer can switch to the radiological convention.

Sources: Fonov et al. 2009; Fonov et al. 2011

07 · Blood supply

Who supplies what

Each part of the brain is fed by particular arteries, so a blocked artery damages a predictable territory. These territories come from a digital atlas built from the MRI scans of 1,298 patients with acute or early subacute ischaemic stroke: the anterior, middle and posterior cerebral arteries and the vertebrobasilar system, in 15 territories per hemisphere. Keep scrolling to turn from the outer (lateral) surface, mostly middle cerebral artery, to the inner (medial) surface, where the anterior and posterior cerebral arteries take over.

Sources: Liu et al. 2023; Tatu et al. 1998

08 · Learn

Go deeper

Each part of the model links to readings that explain what it does and how, the equations scientists use to describe it, what happens when it fails, and where research is heading, from brain–computer interfaces to artificial neural networks. Every statement is linked to its source.

• The basal ganglia and reward

  How deep brain circuits choose actions, build habits and learn from reward, and why the dopamine signal inspired a branch of AI.

  Intermediate

• Blood supply and stroke

  The arteries of the brain and their territories, how flow is regulated, what a stroke destroys minute by minute, and the trials that changed treatment.

  Intermediate

• Brain–computer interfaces

  How implants like BrainGate and Neuralink read intention from motor cortex, the maths of decoding, and the race to restore speech and movement.

  Intermediate