Meet the Scientists

Axel Nimmerjahn, PhD

Professor and Director
Waitt Advanced Biophotonics Center
Francoise Gilot Chair

Innovations and Discoveries:

Using imaging and genetic approaches the Nimmerjahn lab has uncovered how microglia, the resident innate immune cells of the central nervous system (CNS), recognize and respond to disturbances in brain function, and how this knowledge can be leveraged to control inflammatory conditions.
Nimmerjahn's lab has spearheaded the development of new microscopy techniques to measure how cells in the spinal cord encode sensory information. The team showed that astrocytes, a major regulatory cell type in the CNS, show coordinated activity in response to noxious but not innocuous cutaneous stimuli. The findings point to new and unanticipated roles of these cells in pain disorders.
Nimmerjahn and colleagues used cutting-edge microscopy approaches to visualize the blood-brain barrier (BBB) breakdown after stroke. They found that stepwise impairment of different cellular mechanisms accounts for the BBB deficits in stroke, pointing to new ways to treat the disease.

Professor
Systems Neurobiology Laboratory
Vincent J. Coates Chair in Molecular Neurobiology

Innovations and Discoveries:

- Callaway's lab developed a tool that uses a modified rabies virus to trace single connections between neurons, a technique now used across the world.
- The lab used its novel circuit-tracing methods to obtain a detailed map of connections to specific cell types in the basal ganglia, an area of the brain linked to both movement and decision-making and implicated in Parkinson's and Huntington's diseases. These studies provide insight into how different cell types in the basal ganglia structure contribute to motor control and decision-making.
- Callaway mapped the connections between cells in the retina of the eye and the brain and discovered that there's a unique highway of connections that has the sole purpose of letting the eye and brain work together to sense up-and-down or side-to-side movement.

Professor
Gene Expression Laboratory
Benjamin H. Lewis Chair

Innovations and Discoveries:

The Pfaff lab discovered neurons within the spinal cord that form a critical regulatory node for controlling motor activity and developed mouse lines that permit spinal neuron activity to be visualized during walking.
The lab created an in vitro model of spinal muscular atrophy to define the fundamental underpinnings of the genetic pathways that go awry in this disease. The group also worked with a team of San Diego scientists to develop an ALS therapy for humans.
Pfaff's lab used genome sequencing to identify molecular pathways involved in gene regulation and spinal cord development. Using this knowledge, they successfully created functional spinal motor circuitry from embryonic stem cells.

Professor
Laboratory of Genetics
Vi and John Adler Chair for Research on Age-Related Neurodegenerative Disease

Innovations and Discoveries:

The Gage lab models diseases in the laboratory using stem cell technologies. They showed that neurons generated from the skin cells of people with schizophrenia are dysfunctional in early developmental stages, providing a hint as to ways to detect and potentially treat the disease early.
By sequencing the genomes of single cells, Gage and collaborators showed that the genomic structures of individual neurons differ from each other even more than expected. This may help explain differences between closely related individuals.
Gage and his colleagues discovered that the human brain can give rise to new neurons throughout life. He also found that exercise and cognitive enrichment can increase the brain's ability to generate more neurons.

Professor
Molecular Neurobiology Laboratory
Frederick W. and Joanna J. Mitchell Chair

Innovations and Discoveries:

The Goulding laboratory has established a comprehensive genetic toolkit and set of sophisticated behavioral tests that allows them to functionally dissect the circuits in the spinal cord that process sensory information and generate coordinated body movements.
Goulding has leveraged his expertise in spinal neural circuitry to define the pathways that transmit and gate itch and pain, providing a better understanding of the cellular changes that underlie chronic pain and itch.
Goulding's lab has delineated the role that multiple neuronal cell types play in controlling locomotion. A better understanding of these circuits should eventually aid in developing therapies for diseases that affect motor skills and balance.

Professor
Computational Neurobiology Laboratory
Edwin K. Hunter Chair

Innovations and Discoveries:

Tatyana Sharpee is using advanced methods from mathematics, statistics and physics to chart the principles by which neurons in the brain and spinal cord exchange energy and information.
Sharpee developed a concise scheme for how visual neurons can combine selectivity to shapes and textures of visual objects.
Sharpee and collaborators have generated a theory that explains when it becomes advantageous for an organism to use new types of neurons. This theory could help catalogue and determine the number of separate neuronal types in the brain. Extensions of this theory make it possible to compute how much information large numbers of neurons jointly convey about incoming stimuli. Previously, this was only possible to do for a few neurons, and now the method can keep up with the capacity of experimental methods that record thousands of neurons simultaneously.

Professor and Laboratory Head
Computational Neurobiology Laboratory
Francis Crick Chair

Innovations and Discoveries:

The Sejnowski lab is using computer modeling techniques to try to encapsulate what we know about the brain as well as to test hypotheses on how brain cells process, sort and store information.
They developed a new model for how memories are consolidated—or stored in the brain—during sleep. Researchers hypothesized some memories are strengthened during sleep, while other memories, deemed less important, are lost. Revealing more about how the brain stores memories could help researchers understand how memory is affected in disorders such as Alzheimer's disease.
Sejnowski built upon a computer model of how neurons transmit electrical impulses and found an unexpected link between a cellular channel and a potassium current—the ratio of densities between the two determines whether neurons can fire properly, providing new knowledge for symptoms of multiple sclerosis.