Neural Representation of Spectral Densities in IT Cortex

The inferotemporal cortex (IT) has been shown to be crucially involved in the processing of complex stimuli such as objects, scenes and faces. Recently, the representation of synthetic fractals was decoded in IT (O’Connel & Chun, 2014), suggesting for the first time that what IT may really process is the complexity of information from energy and phase offset of an image. Here we used multi voxel pattern analysis (MVPA) to decode how neurons in IT decode information about energy and phase spectra obtained from images of faces and environmental scenes. To this aim, we used functional magnetic resonance imaging (fMRI) to record the Blood Oxygen Level Dependent (BOLD) response while participants were exposed to images of faces or environmental scenes where energy was spectrally matched to several distributions, including white, pink (1/f), Brownian noise. Our preliminary findings suggested that the energy of 1/f noise was reliably decoded in the right hemispheres of the scene (PPA) as well as the face (FFA) IT areas. The specific energy distribution of face stimuli could not be decoded either from activation in FFA or PPA regions.