This dataset contains the results of the simulation of a hyperspectral imaging recording of the exposed cortex of a human brain. Monte-Carlo (MC) simulations of the propagation of visible and near-infrared light in the exposed cortex of human were carried out, and the results of the MC simulation were processed to produce an hypercube, i.e., a set of images at various wavelength. Here, the light propagation of 41 wavelengths from 500 to 900nm were simulated and the images reconstructed. The simulation was based on the MCX software (https://github.com/fangq/mcx). The parameters of the simulations (at every wavelength) can be found in the ConfigurationFiles.zip file (1 per wavelength, named: cfg_WMC_wavelengthNumber). For the full details of the files structure, see: https://github.com/fangq/mcx. The domain used for the simulations was generated from an RGB image of the exposed cortex acquired during a surgical procedure. The image was segmented with a semi-automated procedure into three classes: gray matter, large blood vessel, and capillaries. Pixels were clustered into ten clusters using the K-means algorithm from the python library OpenCV (v4.8.0). The components of each cluster were manually sorted and attributed to the three classes. Three functional regions were defined as 1cm disk based on electrical brain stimulation findings, which lead to three other classes: activated grey matter, activated large blood vessel and activated capillaries. Once the image segmented into six classes, the brain volume was modelled. The binary segmentation masks were replicated along the z axis on 2cm to avoid any photon loss. Then the blood vasculature was modelled using morphological erosion. The structuring element used for the erosion was set to 0 (in pixels) for z=0 (in pixels) and was increased of 1 pixel while increasing z axis. The binary volumes of the six classes were finally merged together with a final isotropic resolution of 75um. The Hypercubes.mat file contains the results of the reconstructed ideal images at the surface of the brain, as calculated in reference [1], with a resolution of 116 x 116 pixels (0.5285 x 05285 mm). The absorption properties considered for this reconstruction are available in the ConfigurationFiles.zip file (variable: mua_WMC). The variables of the Hypercube.mat file are : Reflectance: the reflectance matrix (116 pixel x 116 pixels x 41 wavelengths). Wavelength: the wavelength vector (41 wavelengths) Mean_path_length: the image of the mean photon pathlength for each pixel and each wavelength (116 pixel x 116 pixels x 41 wavelengths) Reference: [1] Yao, R., Intes, X. and Fang, Q., “Direct approach to compute Jacobians for diffuse optical tomography using perturbation Monte Carlo-based photon ‘replay,’” Biomed. Opt. Express 9(10), 4588 (2018).