Current Research
Discovering Neural Circuits That Control Behavior

Karl Deisseroth has created innovative optical tools that enable researchers to manipulate neurons with unprecedented precision and visualize neural circuits in fine detail. Deisseroth and others around the world are using these techniques to further their understanding of how the brain controls behavior, and to explore how neural activity is disrupted by mental illness.

Deisseroth pioneered optogenetics, a technology that uses light to control the activity of specific cell types in the brains of mammals. His original technology genetically introduced a light-activated protein called channelrhodopsin into neurons, allowing the cells to be turned on instantly with the pulse of a laser. His team later created many engineered versions of channelrhodopsin that can act as different kinds of light-activated switches. With this array of tools, researchers can now switch multiple sets of neurons on or off with millisecond precision.

In 2007, Deisseroth’s team used optogenetics to wake sleeping mice by activating specific neurons in the hypothalamus region of their brains. Since then, the researchers have used the technology to investigate how the brain implements different behavioral states and transitions between them. As a practicing psychiatrist, Deisseroth focuses much of his research on understanding brain circuits involved in clinically relevant symptoms and behaviors, including anxiety, depression, and social dysfunction.

To improve observation of the brain’s structure, Deisseroth created CLARITY. The method removes light-scattering fats from biological tissue and introduces a permeable hydrogel as support, generating an optically transparent sample that retains the tissue’s original structure and molecular information. CLARITY is complemented by fiber photometry, an imaging method Deisseroth developed to quantitatively detect traffic along fine connections deep within the intact brains of freely behaving mammals. Deisseroth’s team and labs worldwide are using these techniques – often in combination with optogenetics – to obtain high-resolution information about biological systems while maintaining a global perspective.

Additional support from NIH, DARPA, NSF, and many philanthropic donors and foundations.

Movie: Flythrough movie in a CLARITY brain. Credit: Deisseroth lab.

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