Electronic Thesis and Dissertation Repository

Thesis Format



Master of Science




Martinez Trujillo J.

2nd Supervisor

Inoue W.



Fast spiking (FS) parvalbumin expressing cells are one of the three major subpopulations of GABAergic interneurons. They generally show a consistent set of electrophysiological features across brain areas and species: short and narrow action potentials and capability of high frequency firing. This features are believed to be crucial for fast inhibition and generation of network oscillations associated with various cognitive phenomena. However, it is unclear whether other intrinsic properties of FS interneurons vary across species and/or brain areas. This study map out the subthreshold intrinsic properties of FS neurons of mouse, macaque and human. Features are derived from intracellular recordings of acute slices from two different databases (© 2018 Allen Brain Atlas: Allen Cell Type Database and NHP database from the Martinez Trujillo Laboratory). To classify FS interneurons in primates we developed a model based on parvalbumin specific mouse lines. Our results showed significant differences in almost all considered features. Primate neurons were more alike, having higher excitability and sag amplitude; however, between primates macaque cells reached higher values which may be due to differences in sampled brain region.

Summary for Lay Audience

Our brain is made up of multiple neuron types. The fast spiking cell is a neuron type that has very distinct electrical activity. This electrical activity could be recorded to analyze the properties of the cell. Recordings from fast spiking cells show characteristic thin and short electrical pulses called “spikes” that could reach high spiking frequencies in comparison to other cell types. Fast spiking cells have shown to play a role in mental abilities in primates (monkeys and humans) for example decision making, and attention. Even though commonalities in the electrical features of fast spiking cells have been shown to be present in different species, it is unclear whether what properties of FS neurons might vary across species. In order to understand the differences and similarities of these neurons across species we compare the electrical properties during negative current injections. Our results showed significant differences across species in almost all considered features. The primate neurons were more alike being easily stimulated to get to spikes, however, monkey cells reached higher values which may be explained by differences in the brain areas that we sampled.