More than two thousand auditory cortical spectro-temporal receptive fields (STRFs) of the ferret were analysed by Principal Component Analysis (PCA) to reveal their dominant properties. Results show that cortical levels of mammalian auditory processing enhance relatively low modulation spectral components of the signal around 3 Hz, using relatively broad spectral processing channels of the order of octave or more, evaluating mean spectral values and local spectral slopes within such frequency channels. These observations are consistent with some engineering techniques shown to be effective in machine recognition of speech.
Bibliographic reference. Mahajan, Nagaraj / Mesgarani, Nima / Hermansky, Hynek (2014): "Principal components of auditory spectro-temporal receptive fields", In INTERSPEECH-2014, 1983-1987.