Spatiotemporal Trajectories in Resting-state FMRI Revealed by Convolutional Variational Autoencoder
Xiaodi Zhang1, Eric Maltbie1, and Shella Dawn Keilholz1
1BME, Emory University/Georgia Tech, Atlanta, GA, United States
We trained a convolutional variational
autoencoder to extract spatial temporal patterns from resting-state fMRI data.
The extracted latent dimensions are spatially aligned with previous findings,
but also provide temporal information in addition.
Figure
3. The latent dimensions can be organized into 6 groups (shown in rows) based
on their spatial similarities. Panel
A shows how the spatial profile at the max-variance time (in figure 2) changes
when sliding a single latent variable from -3 to +3. Panel B shows the spatial
similarities among latent variables, which were clustered using K-means
clustering (K = 6). The cluster number and the variance explained were also
shown. Panel C shows the weighted mean functional connectivity of each cluster
of latent variables.
Figure
2. Spatial temporal patterns extracted by latent dimensions. Each subplot is obtained by making one latent
variable equal to +3 (+3σ for Gaussian distribution) while fixing the rest of the latent variables at zero. The x-axis is time in
seconds. The y-axis is the 246 parcels. The patterns have arbitrary units, but
all subplots share the same display scale so that higher variance results in higher
contrast. The 32 latent variables are already organized in 6 clusters (see
figure 3). The black cursor indicates the maximum variance time.