[6] The main component of her thesis was the development of a theory for how the brain interprets subtle sensory cues within the context of its internal experiential and motivational state to extract unambiguous representations of the external world.

Rajan's early, influential work[10] with Abbott and Haim Sompolinsky integrated physics methodology into mainstream neuroscience research — initially by creating experimentally verifiable predictions, and today by cementing these tools as an essential component of the data modelling arsenal.

[11] At Princeton, she and her colleagues developed and employed a broad set of tools from physics, engineering, and computer science to build new conceptual frameworks for describing the relationship between cognitive processes and biophysics across many scales of biological organization.

[13] To understand how the brain might receive complex inputs but detect individual features, Rajan treated the problem like a dimensionality reduction instead of the typical linear model approach.

[14] In June 2018, Rajan became an assistant professor in the Department of Neuroscience and the Friedman Brain Institute at the Icahn School of Medicine at Mount Sinai.

As the Principal Investigator of the Rajan Lab for Brain Research and AI in NY (BRAINY),[15] her work focuses on integrative theories to describe how behavior emerges from the cooperative activity of multi-scale neural processes.

[17]  Her models are based on experimental data (e.g., calcium imaging, electrophysiology, and behavior experiments) and on new and existing mathematical and computational frameworks derived from machine learning and statistical physics.

In collaboration with Karl Deisseroth and his team at Stanford University,[18] such models revealed that circuit interactions within the lateral habenula, a brain structure implicated in aversion, were encoding experience features to guide the behavioral transition from active to passive coping – work published in Cell.

[24] In 2022, Rajan was promoted to Associate Professor[25] with tenure in the Department of Neuroscience and the Friedman Brain Institute at the Icahn School of Medicine at Mount Sinai.