dimensionality reduction
PCA
NMF
ICA
faces
words
bodies
scenes
food
social interactions
yeet
eigendecomposition
kayfabe
large-scale datasets
high-SNR neuroimaging
modern analysis techniques
high-dimensional code
low-dimensional code
explains many invariances observed in visual cortex
readily interpretable!
high representational capacity, expressive
makes learning new tasks easier
" [...] the topographies in VT cortex that support a wide range of stimulus distinctions, including distinctions among responses to complex video segments, can be modeled with 35 basis functions"
~87 dimensions of object representations in monkey IT
"A progressive shrinkage in the intrinsic dimensionality of object response manifolds at higher cortical levels might simplify the task of discriminating different objects or object categories."
detecting high-dimensional codes requires large datasets!
high representational capacity, expressive
makes learning new tasks easier
8 subjects
7 T fMRI
"Have you seen this image before?"
continuous recognition
same geometry,
new perspective!
ambient
dimensions
voxel 1
voxel 2
rotation
latent
dimensions
latent dimensions sorted by variance
variance along the dimension
variance along each dimension
stimulus-related signal
trial-specific noise
generalizes
... across stimulus repetitions
... to novel images
trial 1
trial 2
neurons (or) voxels
stimuli
Learn latent dimensions
Step 1
Step 2
Evaluate reliable variance
If there is no stimulus-related signal, expected value = 0
latent dimensions sorted by variance on the training set
reliable variance on the test set
more data
more dimensions?
i love sci-fi and am willing to put up with a lot. Sci-fi movies/tv are usually underfunded, under-appreciated and misunderstood. I tried to like this, I really did, but it is to good tv sci-fi as babylon 5 is to star trek (the original). Silly prosthetics, cheap cardboard sets, stilted dialogues, cg that doesn't match the background, and painfully one-dimensional characters cannot be overcome with a'sci-fi'setting. (I'm sure there are those of you out there who think babylon 5 is good sci-fi tv. It's not. It's clichéd and uninspiring.) while us viewers might like emotion and character development, sci-fi is a genre that does not take itself seriously (cf. Star trek). [...]
i love and to up with a lot. Are, and. I to like this, I really did, but it is to good as is to (the).,,, that doesn't the, and characters be with a''. (I'm there are those of you out there who think is good. It's not. It's and.) while us like and character, is a that does not take [...]
vs
generalizes
... across stimulus repetitions
... to novel images
... across participants
subject 1
subject 2
neurons (or) voxels
stimuli
Learn latent dimensions
Step 1
Step 2
Evaluate reliable variance
limited by 1,000 shared images
similar neural population statistics
also shared across individuals!
10,000 neurons
2,800 images
calcium imaging
low-rank
high-rank
1
10
100
1,000
4
8
20
1,000
large spatial scale
small spatial scale
1
1,000
30 mm
80 μm
number of neurons in human V1
spacing between neurons
a code that leverages all latent dimensions
high-dimensional
or
striking universality
The Bonner Lab!
The Isik Lab!