A variety of neural structures contribute to the brain’s ability to process and modulate visual information. One of the subcortical areas that provide input projection to visual cortex and thus influence the properties of the visual response is Basal Forebrain (BF). The Basal Forebrain is predominantly characterized by its· cholinergic projection patterns to the visual cortex. The functional contribution of this input is only starting to become understood. We propose that cholinergic modulation coming from BF will significantly impact single neuronal responses of the primary visual cortex (V1) in Long-Evans rats. The primary goal of this project is to understand the Basal Forebrain’s role in the processing of the visual information in the V1 and its effect on the visual system activity. To answer this question, we used cutting-edge techniques like viral tracing and optogenetic stimulation of neuronal circuits paired with electrophysiological recordings in the primary visual cortex. Precisely, we injected the modified Rabies virus (RV) into the V1 to retrogradely trace inputs coming from the Basal Forebrain. The RV carries opsins to allow for both activation and inhibition of infected cells in the Basal Forebrain. We hypothesize that the manipulation of the BF changes the selectivity of single cells in the V1. Indeed, our preliminary results confirm this hypothesis. The most prominent observation In our experimen1 is a significant change in firing rate when showing various directions of drifting gratings at optimal Spatial Frequency (SF), Temporal Frequency (TF), and Size. However, this change was different for different layers (depth) in the cortex. All layers tend to have a lower firing rate; however, the cell around layer IV tend to have an increased firing rate. Perhaps the most important result is the change in the optimal stimulus size. Most cells showed decreased optimal stimulus size, and the difference between conditions tends to be stronger in the upper layers than in the deep layers of the V1. Our preliminary results suggest that the Basal Forebrain plays a substantial role in the modulation of the center-surround interactions. These results are in line with the previous data from Lyon Lab (Lean et al., 2018), showing that the main inputs from BF are corning into the GABAergic cells in the V1. The project is supported by the National Science Center, Poland (2020/39/DINZ4/01881) for AT
About the speaker
Postdoctoral researcher at ICTER. PhD degree from Nencki Institute of Experimental Biology, Polish Academy of Sciences
