dimensionality reduction

Pupillary manifolds: uncovering the latent geometrical structures behind phasic changes in pupil size. We show that phasic changes in pupil size are inherently low-dimensional: they can be reconducted to a latent manifold that efficiently represents autonomic balance.

Abstract The size of the pupils reflects directly the balance of different branches of the autonomic nervous system. This measure is inexpensive, non-invasive, and has provided invaluable insights on a wide range of mental processes, from attention to emotion and executive functions.

Phasic changes in pupil size are strikingly low-dimensional! In a new preprint, we show that very different tasks and processes map onto a very similar, low-dimensional latent space. We suggest that phasic changes in pupil size originate from a set of distinctive fingerprints that describe a pupillary manifold: a latent space that is highly constrained by the underlying physiological structures, i.e. the balance between different branches of the ANS.

Recent studies have shown that brain lesions following stroke can be probabilistically mapped onto disconnections of white matter tracts, and that the resulting “disconnectome” is predictive of the patient’s behavioral deficits.