Investigation of a putative circuit in the mouse retina

by Juan Diego Prieto Ramirez
Doctoral thesis
Date of Examination:2023-08-14
Date of issue:2024-06-27
Advisor:Prof. Dr. Tim Gollisch
Referee:Prof. Dr. Silvio Rizzoli
Referee:Dr. Jan Clemens
Persistent Address: http://dx.doi.org/10.53846/goediss-10570

 

 

Files in this item

Name:FINAL_FINAL_Thesis_NoCV.pdf
Size:2.71Mb
Format:PDF

The following license files are associated with this item:

Abstract

English

Retinal ganglion cells of the vertebrate retina are tuned to detect specific features of the visual scene and effectively decompose it into different channels that are transmitted to and used by the brain to create the visual percept. Traditionally, the tuning of ganglion cells has been studied using simple artificial light stimuli, but more complex stimuli are useful to uncover naturalistic features that ganglion cells detect. Previous work in the lab designed tailored visual stimulation that simulates the kind of global movement of the visual scene that is caused by saccadic movements of the eyes. It consisted of a series of grating fixations in one of four spatial phases separated by brief transitions. Using this stimulation paradigm, OFF- transient alpha retina ganglion cells of the mouse were found to increase their firing rate when the grating after the transition was the same as the one before the transition. Accordingly, these cells were dubbed image-recurrence sensitive (IRS) cells. However, it was not clear what kind of synaptic circuitry was responsible for the responses to the recurrence of images. In my research, I used whole-cell patch clamp recordings to examine the excitatory and inhibitory inputs of these cells during stimulation with pairs of flashes of either positive (white) or negative (black) contrast, to evaluate their dependence on previous stimulus history. I compared these inputs to those of OFF-sustained alpha cells, which do not possess image- recurrence sensitivity. I found that the inhibitory input was similar in IRS and non-IRS cells but not so their excitatory input. In IRS cells, excitation did not show significant adaptation when driven by consecutive flashes of negative contrast, and positive contrast disinhibited the excitatory input driven by subsequent negative contrast. I also found that the temporal course of the total excitatory conductance of IRS cells obtained during recurring contrast transitions (white to white, black to black) correlates well with the temporal course of IRS spiking responses during saccade-like stimulation, which indicates that the conductances so measured could well be used to explain the image-recurrence sensitivity.
Keywords: Retina; Ganglion cells; Electrophysiology; Mouse
 
Statistik