Researching how brains organize movements into actions
What excites us?
The nervous system orchestrates an incredible array of actions by coordinating movements across the body. Using coordination we make music, play sports, communicate, and move about the world. Even walking requires moving our legs, arms, trunks, and heads in conjunction, and we do it all without a conscious thought.
At first glance, coordination seems hard-wired. A concert violinist makes a sequence of precise movements perfectly and on cue. But beneath the surface, the neural processes that create these movements are anything but fixed! The violinist can adapt the sequence to another tempo, improvise a solo in key, or learn a new song from scratch. This fundamental ability to adapt and learn coordination is critical for populating our repertoire of actions as children.
Questions needing answers
How does the brain transform movement goals into patterns of activity that coordinate muscles across the body?
Which cells and synapses encode learning about coordination, particularly as developing animals discover new and better ways to move?
Why is coordination surprisingly vulnerable in neurodegenerative and developmental disorders?
A simple case of a universal problem
We create actions by combining and patterning movements. For larval zebrafish, movements are rudimentary because their bodies are simple. Still, by combining these movements zebrafish can make elegant actions like hunting prey, evading predators, and navigating flows. Zebrafish possess miniature versions of key neural structures we use to coordinate our bodies like the cerebellum, brainstem, and spinal cord. And because they are transparent, zebrafish offer unrivaled access to the inner workings of these structures.
Listening to the brain,
from synapses to circuits
To understand how brains organize movements, we record neural activity in zebrafish while they control their bodies. We use electrodes to reveal the operations of individual cells and synapses, and we image activity across cell populations spanning the entire brain. Our approach affords a unique opportunity to explain not only how neural circuits pattern movements across the body, but also how synapses let neurons cooperate within those circuits. These precise recordings are essential for understanding where and how learning remodels the brain.
Deconstructing circuits cell by cell
Because zebrafish possess so few neurons (1 for every 1 million in your brain), any given cell can contribute indispensably to a behavior or computation. With fewer synapses separating most neurons from sensations and actions, the fish can give us a complete picture of how brains shape movements holistically. To this end, we delete and activate neurons in live fish to piece together how the nervous system operates from the bottom up. And because the zebrafish is a genetic model organism, we can access cutting-edge molecular tools for manipulating cell activity and signaling.
A computational bridge from brains to behavior
Modeling allows us to efficiently test ideas about the core computations and neural implementations underlying behavior. Often, simulations open otherwise inaccessible lines of inquiry. We use computational models to ask which movements are optimal, how elements act together in circuits, and how a neuron’s properties shape its response to input.
