This dataset is related to the article titled "Aberration correction in long GRIN lens-based microendoscopes for extended field-of-view two-photon imaging in deep brain regions". Authors: Andrea Sattin1,2,*, Chiara Nardin1,2,*, Simon Daste3, Monica Moroni2,4, Innem Reddy5, Carlo Liberale5, Stefano Panzeri2,6, Alexander Fleischmann3, Tommaso Fellin1,2,# *equal contribution; #corresponding author: tommaso.fellin@iit.it Affiliations: 1Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, Genova, Italy 2Neural Coding Laboratory, Istituto Italiano di Tecnologia, Genova and Rovereto, Italy 3Department of Neuroscience and Carney Institute for Brain Science, Brown University, Providence, USA 4Neural Computation Laboratory, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy 5Biological and Environmental Sciences and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia 6Institute for Neural Information Processing, Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany DOI: https://doi.org/10.7554/eLife.101420.3 Description: Data contained in this dataset were used to generate Figure 5,6 and figure supplements 1,2 related to Figure 6. Data are synthetic calcium t-series (tiff files) simulating the activity of neuronal populations virtually sampled using the 6.4 mm-long corrected microendoscope. We generated synthetic calcium t-series to evaluate the impact of the improved optical performance of long aberration corrected microendoscopes on the ability to extract information about neuronal activity. To build synthetic calcium data, we first generated neurons with 3D distribution and anatomical properties (i.e., cell size and cell density) similar to those measured in the mouse olfactory cortex, the ventral brain region which we imaged in vivo, and the biophysical characteristics of one of the two indicators used in our experiments, jGCaMP8f. We then simulated the optical sampling of 3D volume of neurons with the point spread function (PSF) properties of the uncorrected and corrected microendoscopes previously characterized. Fluorescence signals integrated over the PSF volume were then projected on a 2D matrix of pixels in time, with a frequency of 30 Hz, to obtain synthetic t-series (duration: 5 min).