2025 Theses Doctoral

Electric-color Processing in the Electrosensory Lateral Line Lobe

Zadina, Abigail

In the electrosense, perception of the electrical qualities of objects relies on detecting modulations in the electric organ discharge (EOD), pulses the fish emits to generate an electric field. However, the electrosense of weakly-electric fish is blurry. Unlike vision, which uses a lens to focus images, electrosensory systems lack a focusing mechanism.

Hence, electrical images of behaviorally relevant objects, like prey, vary greatly in amplitude and shape depending on their distance and location relative to the fish’s skin. In a scheme analogous to color vision, which relies on comparisons between photoreceptor responses, it has been proposed that fish could represent an object’s electrical properties as ‘electric-colors’ by comparing the amplitude and shape distortions of the object’s electric image. Here, using naturalistic stimuli, I recorded local field potentials from the sensory input layers in the active zones of the electrosensory lateral line lobe (ELL).

I show that the dorsolateral zone may separately process EOD amplitude and shape information across two layers of granular cells. Additionally, recordings from principal output neurons in the ELL show that EOD amplitude and shape information may be combined in ways not expected based on classic E-cell (excited by electrosensory stimuli) and I-cell (inhibited by electrosensory stimuli) designations. These results highlight the need to re-examine the functional responses of cells in the ELL to account for multiple axes of stimulus information.