M81 has the nearest active nucleus with broad H{alpha} emission. A detailed study of this galaxy's centre is important for understanding the innermost structure of the AGN phenomenon. Our goal is to seek previously undetected structures using additional techniques to reanalyse a data cube obtained with the GMOS-IFU installed on the Gemini North telescope (Schnorr Muller et al., 2011MNRAS.413..149S). We analysed the data cube using techniques of noise reduction, spatial deconvolution, starlight subtraction, PCA Tomography and comparison with HST images. We identified a hot bubble with T>43500K that is associated with strong emission of [NII]{lambda}5755{AA} and large [OI]{lambda}6300/H{alpha} ratio, as well as with a bluish continuum, surrounded by a thin shell of H{alpha}+[NII] emission. We also reinterpret the outflow found by Schnorr Muller et al. (2011MNRAS.413..149S) showing that the blueshifted cone nearly coincides with the radio jet, as expected. We interpret the hot bubble as likely to be caused by post starburst events that left one or more clusters of young stars, somewhat similar to the ones found at the centre of the Milky Way, like the Arches and the IRS 16 clusters. Shocked structures from combined young stellar winds or supernova remnants are probably the cause of this hot gas and the low ionization emission.