Jessica Brinegar

Jessica Brinegar

Jessica Brinegar is completing her Biology requirements to enter a master’s program in Physician Assistant Studies by Summer 2022. She has experience as a medical assistant to an ear, nose, and throat surgeon and as a medical scribe in the Emergency Department at MountainView Regional Medical Center. In her free time, she is an avid piano player, loves to ride her bike, and has a passion for traveling as this broadens her perspective and the way she views the world.

Project Description:

Jessica developed an interest in neurophysiology while taking a physiology course with Dr. Graciela A. Unguez. Following several meetings discussing potential research opportunities that would match their interests, they have set out to characterize the myogenic stem cells in the weakly electric fish Sternopygus macrurus – commonly referred to as the yellow striped knifefish.

Sternopygus macrurus has an electric organ composed of cells called electrocytes that derive from skeletal muscle cells. Mature electrocytes are highly specialized cells that no longer contain the structures that make their precursor muscle cells contract and generate force, but rather function solely to generate the electric discharge used by the fish to navigate its surroundings, look for prey, and find mates. Although these electrocytes lack all contractile units, they retain some muscle characteristics including their multinuclearity and close association with many peripheral myogenic-like stem cells.


Electric field around a fish


Electrocytes of S. macrurus are driven by the nervous system at a continuous rate of 50-200 Hz throughout the life of the fish. In contrast, the neuronal input to the skeletal muscle fibers is intermittent and at frequencies of 8-100 Hz.

It is of interest how the stem cells associated with electrocytes can withstand this type of electrical input from the nervous system that in muscle tissue of any other vertebrate would be fatal. This work aims to determine what allows them to survive these electrical patterns by comparing different properties of stem cells associated with electrocytes and skeletal muscle cells. This data could inform evolution of novel animal cell types and could have significant implications in human health as it relates to disorders of hyperactivity of the nervous system.


  • Project description, timeline, and milestones developed with mentor; on file with DSP
  • Complete half of project milestones
  • Complete project
  • Present scholarly work at URCAS
  • Attend a professional conference (without presenting)
  • Author or co-author a manuscript submitted for publication
  • Promote #DiscoveryScholars ten times on social media
  • Apply for graduate or professional school


Jessica’s Mentor: Dr. Graciela A. Unguez

Graciela A Unguez

Since her undergraduate training, Dr. Unguez’s research interests focus on studies aimed at understanding how properties of mature cells and their connections in the nervous system respond to injury, changes in electrical activity and other environmental perturbations. She has addressed this question over her career years using non-human primates, felines, rodents and electric fishes. Dr. Unguez is strongly committed in promoting the advancement of all students (undergraduate and graduate), postdoctoral trainees and early-stage faculty – especially those belonging to all marginalized or underrepresented groups – in STEM disciplines. She carries this commitment through her service in local and national committees and organizations.