TITLE: Whole MILC: generalizing learned dynamics across tasks, datasets, and populations 

ABSTRACT: Behavioral changes are the earliest signs of a mental disorder, but arguably,
the dynamics of brain function gets affected even earlier. Subsequently,
spatio-temporal structure of disorder-specific dynamics is crucial for early
diagnosis and understanding the disorder mechanism. A common way of learning
discriminatory features relies on training a classifier and evaluating feature
importance. Classical classifiers, based on handcrafted features are quite
powerful, but suffer the curse of dimensionality when applied to large input
dimensions of spatio-temporal data. Deep learning algorithms could handle the
problem and a model introspection could highlight discriminatory
spatio-temporal regions but need way more samples to train. In this paper we
present a novel self supervised training schema which reinforces whole sequence
mutual information local to context (whole MILC). We pre-train the whole MILC
model on unlabeled and unrelated healthy control data. We test our model on
three different disorders (i) Schizophrenia (ii) Autism and (iii) Alzheimers
and four different studies. Our algorithm outperforms existing self-supervised
pre-training methods and provides competitive classification results to
classical machine learning algorithms. Importantly, whole MILC enables
attribution of subject diagnosis to specific spatio-temporal regions in the
fMRI signal.
Behavioral changes are the earliest signs of a mental disorder, but arguably,
the dynamics of brain function gets affected even earlier. Subsequently,
spatio-temporal structure of disorder-specific dynamics is crucial for early
diagnosis and understanding the disorder mechanism. A common way of learning
discriminatory features relies on training a classifier and evaluating feature
importance. Classical classifiers, based on handcrafted features are quite
powerful, but suffer the curse of dimensionality when applied to large input
dimensions of spatio-temporal data. Deep learning algorithms could handle the
problem and a model introspection could highlight discriminatory
spatio-temporal regions but need way more samples to train. In this paper we
present a novel self supervised training schema which reinforces whole sequence
mutual information local to context (whole MILC). We pre-train the whole MILC
model on unlabeled and unrelated healthy control data. We test our model on
three different disorders (i) Schizophrenia (ii) Autism and (iii) Alzheimers
and four different studies. Our algorithm outperforms existing self-supervised
pre-training methods and provides competitive classification results to
classical machine learning algorithms. Importantly, whole MILC enables
attribution of subject diagnosis to specific spatio-temporal regions in the
fMRI signal.
Whole MILC: generalizing learned dynamics across tasks, datasets, and populations
http://arxiv.org/abs/2007.16041v2