Thesis defense Patrick Jendritza (Donders series 553)

18 May 2022

Promotor: Prof. dr. Pascal Fries

Neural recordings and optogenetics in the visual cortex of the marmoset

The common marmoset has emerged as a key model in neuroscience. Marmosets are small primates that can exhibit complex behaviors and show great potential as transgenic models. This thesis contributes to establishing the marmoset as a model for visual neuroscience by developing and applying novel techniques in order to elucidate the function of the visual cortex. All technical advancements were designed with the behavioral peculiarities of the marmoset in mind. Head-free eye tracking was developed in order to allow measurements of eye position from naïve, non-implanted animals. Efficient receptive field mapping was implemented to be compatible with the natural tendency of marmosets to point their gaze at visually salient objects. Furthermore, this thesis describes a novel approach to record neural data from multiple brain areas simultaneously, while enabling optogenetic stimulation. The application of the method is demonstrated by presenting single- and multi-unit data recorded in areas V1 and V6. It is further shown that optogenetic stimulation in area V6 can improve detection performance. Moreover, this thesis describes several findings that resulted from analysis of neural data from area V1 of the awake marmoset. Specifically, the changes in power and peak frequency of gamma oscillations are described and compared to previous work. Additionally, a quantification of single unit firing and their spike-LFP phase locking is presented, as well as a comparison of the phase-locking and tuning properties of different putative cell types as identified through spike waveform analysis.