#6 Kate Jeffery: Grid cells in 3D, entropy & climate change

Kate Jeffery is the head of the school of psychology & neuroscience at the University of Glasgow (formerly at UCL). This episode is all about grid cells (background info), which Kate was already recording in the 1990s. We discuss how grid cells' rate maps differ when the rats climb in 3D spaces. Here we cover anything from cross-species comparisons (bats, birds), to self-organizing dynamics, and symmetry breaking. Kate also shares her (maybe unpopular) thoughts that the hexagonal grid regularity is not functional but a by-product. We also get physics-y by discussing entropy, evolution, complexity and how they link to memory and the arrow of time. At the end there is career advice and some thoughts on climate change.

For Apple Podcast users, find books/papers links at: https://akseliilmanen.wixsite.com/home/post/pod06

Not familiar with place, grid or head direction cells? Here is my 5min primer.

• Kate's Website
• Kate's publications:
• Jeffery et al., 2015 - Neural encoding of large-scale three-dimensional space—properties and constraints paper
• Casali et al., 2019 - Altered neural odometry in the vertical dimension paper
• Jeffery et al., 2019 - On the Statistical Mechanics of Life: Schrödinger Revisited paper
• Jeffery et al., 2020 - Transitions in Brain Evolution: Space, Time and Entropy paper
• Grieves et al., 2021 - Irregular distribution of grid cell firing fields in rats exploring a 3D volumetric space paper
• Jeffery, 2022 - Symmetries and asymmetries in the neural encoding of 3D space paper
• Rae et al., 2022 - Climate crisis and ecological emergency: Why they concern (neuro)scientists, and what we can do paper
• Other reading mentioned:
• Cheng, 1986 - A purely geometric module in the rat's spatial representation paper
• My article on Michel Foucault and climate change deniers
• My Twitter @akseli_ilmanen
• Email: akseli.ilmanen[at]gmail.com
• The Embodied AI Podcast, my blog, other stuff
• Music: Space News, License: Z62T4V3QWL

Timestamps:

(00:00:00) - Intro

(00:02:14) - Missing out on a Nobel Prize

(00:11:05) - Place cells & grid cells interactions

(00:15:19) - Grid cells and rats climbing in 3D

(00:27:24) - (Spatial) ecological niches of rats, bats and birds

(00:32:55) - Self-organizing dynamics

(00:35:36) - 'Speed' in navigating physical vs abstract spaces

(00:40:19) - 3D = 2D planes stitched together?

(00:46:22) - Symmetry breaking in

(00:50:20) - 'A purey geometric module' (Cheng, 1986)

(01:01:24) - Why are grid cells grid-like?

(01:05:22) - Kate's (grid cell) secrets

(01:08:18) - Entropy, evolution, and complexity

(01:17:45) - Memory as metastable states

(01:22:07) - Entropy, memory & the arrow of time

(01:25:03) - Career Advice

(01:28:35) - Climate change & sociology

(01:38:07) - New position in Glasgow