Grid cells and the brain’s metric for navigation
PAPER VIII — COMPUTATION · QUESTION 32 OF 32
In plain terms: The free lecture by those who found the cells that fire in a triangular grid as an animal moves.
The question as set
Grid cells tile the plane hexagonally. State what a navigational metric must supply, and decide whether the entorhinal code supplies it or merely correlates with it.
The question in Paper VIII · Its section on the reference page
The question in context
This is question 32 of the 32 set in Paper VIII — Computation of The Truly Hardest Exam in the World, the examination of The College of All Minds. In the College’s subject index it is filed under Geodesy and navigation. Like every question of the College, it carries three references of record, verified live at publication and described twice — technically, and in plain terms — so the ground can be judged before it is walked. The response required is an argument, not a survey, of at most three thousand words, as technical as the question demands and no more.
The references of record
Grid cells and the brain’s map of space (Nobel lecture)
The code described by its discoverers: hexagonally periodic firing across nested modules, proposed as a metric for path integration.
In plain terms: The free lecture by those who found the cells that fire in a triangular grid as an animal moves.
The computational reading and its rivals: path integration against boundary-anchored and sensory accounts of the same periodicity.
In plain terms: The free peer-reviewed entry setting out what the grid is thought to compute, and what else could explain it.
Vector-based navigation and grid-like representations
The claim tested in silico: grid-like units emerging in agents trained to navigate, and what emergence does and does not show about necessity.
In plain terms: The free study in which artificial navigators grew their own grids — evidence about what the code is for.
Background: Grid cell · Path integration