iGluSnFR wide-field imaging responses to 2-72 Hz flicker

Human primary visual cortex (V1) responds more strongly, or resonates, when exposed to ~10, ~15-20, ~40-50 Hz rhythmic flickering light. Full-field flicker also evokes perception of hallucinatory geometric patterns, which mathematical models explain as standing-wave formations emerging from periodic forcing at resonant frequencies of the simulated neural network. However, empirical evidence for such flicker-induced standing waves in the visual cortex was missing. We recorded cortical responses to flicker in awake mice using high spatial resolution widefield imaging in combination with high temporal resolution glutamate-sensing fluorescent reporter (iGluSnFR). The temporal frequency tuning curves in the mouse V1 were similar to those observed in humans, showing a banded structure with multiple resonance peaks (8 Hz, 15 Hz, 33 Hz). Spatially, all flicker frequencies evoked responses in V1 corresponding to retinotopic stimulus location, but some evoked additional peaks. These flicker-induc..., In vivo glutamate imaging was performed in awake head-fixed animals using a charge-coupled device (CCD) camera. To capture the fast glutamate sensor iGluSnFR kinetics, images of iGluSnFR activity were captured at 150 Hz sampling rate. The glutamate fluorescent indicator was excited using blue LED light (Luxeon K2, 470 nm), which was band-pass filtered using an optical filter (Chroma Technology Corp, 467-499 nm). Light emitted from excited fluorescent indicators was passed through a band-pass optical filter (Chroma, 510 to 550 nm; Semrock, New York, NY) and a macroscope composed of front-to-front optical lenses. The focal length of the lenses was adjusted such that the field of view was 8.6 × 8.6 mm (128 × 128 pixels, with 67 μm per pixel). To minimize the effect of hemodynamic signal originating from large cortical blood vessels, we focused the optical lens at ~1 mm depth.
Steady-state visual evoked potentials. We used a custom-built setup of white light-emitting diodes (LEDs;..., , # iGluSnFR wide-field imaging responses to 2-72 Hz flicker

[https://doi.org/10.5061/dryad.vdncjsz42](https://doi.org/10.5061/dryad.vdncjsz42)

## Description of the data and file structure

There are two ZIP files containing widefield imaging DATA from two visual stimulation protocols used in the experiment: (1) sine-wave modulated luminance changes (flicker; Spatiotemporal_resonance_DATA_Flicker.zip) and (2) pulse stimulation (Spatiotemporal_resonance_DATA_Pulse.zip). Data is organized in folders. Each folder contains single-animal data, e.g. Glu1, Glu2 etc.

Organization of the folders:

#### (1) **Spatiotemporal\_resonance\_DATA\_Flicker.zip**

In each animal's data folder you will find a subfolder named \"Ready4preprocessing\" with the following file types:

* datafiles (*.raw); scripts to load this datafile type can be found in Spatiotemporal_resonance_CODE.zip, file named *imreadallraw.m*, for an example how to use it, see *1_Preprocessing_singleTrial_SSVER.m* line 154
* stimulus ...