01 · State to behavior
How does brain-wide activity shape what an animal does?
I examine how neural dynamics and molecular signaling make particular responses more or less likely as an animal interacts with its environment.
PhD candidateCambridge, MA
Marc Duque Ramírez
Systems neuroscience · Engert Lab
Harvard University
Brain-wide dynamics · Behavioral transitions
How brain states shape behavior—and what makes them change.
I study how brain-wide dynamics define states that make particular behaviors more or less likely, and how sensory evidence, circuits, neuromodulators, and drugs move the brain from one state to another.
Whole-brain calcium imaging
7 dpf · H2B-GCaMP7f© Marc Duque Ramírez
Research question
Two linked questions.
How does ongoing neural activity shape behavior, and how does activation of specific circuits—through neuromodulators and receptors—cause that activity to change?
02 · Transition control
What moves the brain from one state to another?
I ask how circuits, neuromodulators, and receptors integrate sensory evidence and experience, then initiate or reverse a transition between brain states.
01 · Behavioral transition
When action becomes futile.
In a tail-free virtual-reality assay, swimming initially produces visual feedback. When that feedback is removed, the same actions become futile: fish first increase their effort, then transition to passivity. We are testing how the serotonergic dorsal raphe and its downstream circuits compute futility and modulate this transition.
© Marc Duque Ramírez
02 · Chemical perturbation
Compounds that change state.
In humans, ketamine and psychedelics can produce profound and persistent changes in brain state after a single dose. We study how these compounds act through specific receptors, cell types, circuits, and neuromodulators to alter brain dynamics and behavior. Our work showed that ketamine persistently suppresses futility-induced passivity through plasticity in a norepinephrine–astroglial circuit; we are now adapting the assay to screen for new antidepressant compounds.
© Duque et al. 2025
03 · General anesthesia
A reversible whole-brain transition.
General anesthetics produce a clinically important, profound, and reversible transition in brain state, yet its circuit-level mechanisms remain poorly understood. We use larval zebrafish to identify the neural dynamics and circuits that underlie this transition.
© Marc Duque Ramírez
Explore in detail
Research directions.
01Futility-induced passivityA virtual-reality assay for studying the switch from struggling to giving up.→02Ketamine & psychedelicsHow chemical perturbations produce lasting changes in brain and behavioral states after a single dose.→03General anesthesiaWhole-brain dynamics during induction, loss of responsiveness, and recovery.→04Model organisms & imagingLarval zebrafish, light-sheet microscopy, and transparent adult fish.→