Journal Club

Stephen M

4/21/21

The Hope

Demonstrate the feasibility of decoding human thought by translating brain activity into an image

The Plan

  • Train an end-to-end mental image generation framework
  • General architecture is to use a VAE to map brain signals and images to a latent space, and then "align" these latent spaces

The Data

  • Two sessions: image presentation session and a mental imagery session

Encoder Overview

Auto Encoder

Variational AE

Variational AE

\(\alpha\)-GAN

  • Combines VAE with GAN

Combining The Approaches

Framework

E_e(.) \\ E_f(.) \\ R_i(.)

EEG Encoder

fMRI Encoder

Image Reconstructor

Overall, a pretty simple idea. I don't think the architecture is too convoluted

Now that we have a "latent space" that is created from the image features, we can look at the other components

Encoders

  • Literature on EEG signal extraction

Unlike the EEG signal which can be directly used to train the learning model [...]

Encoders use the same architectures

Encoders

We firstly employ Pearson Correlation Coefficient to select k most related features of the EEG signal or the fMRI signal according to each dimension of the m dimension image feature representation vector

Then, we construct m
parallel Bayesian regression sub-models. Each Bayesian regression predicts the
value of one corresponding dimension of the image feature representation vector
based on k most related features of the EEG signal or the fMRI signal

Data

  • fMRI - EEG
    • 5 subjects. Pretty low resolution imaging
  • Visual Stimuli
    • 20 categories with 50 examplars per category
  • Data collection
    • 5 sessions for image experiment

Training

  • \( \alpha\)-GAN architecture is given in text
  • Training doesn't make sense to me
    • What atlas do they use?
    • Bad assumptions
    • Bad model
  • Asses model using SSIM and MSE

Results

Fig 4

Summary and Discussion

  • There is talk about split-test data on training?? No validation?
  • What about the imagining dataset? Never talks about it

Thoughts

  • I would NOT accept this paper
  • Methods needs more detail
  • Really coarse approach

I think that there is a better way:

HCP (along with Haxby) has publically available datasets of people watching movies

VAE-GAN Brain Decoder Paper

By smazurchuk

VAE-GAN Brain Decoder Paper

This is a slide deck I made for a journal club presentation. It presents an arxiv pre-print that tries to "decode human imagination"

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