Adaptation to stimulus statistics in the mammalian sensory systems

• Main Author: Garcia-Lazaro, Jose Alberto
• Published: University of Oxford 2007
• Subjects: 612.8
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494398

The aim of this thesis is to investigate adaptive processes occurring at different time scales and in different sensory modalities. For this purpose, I use stimuli featuring well defined statistical properties. It has been reported that the amplitude and pitch fluctuations of natural soundscapes often exhibit 1/f spectra, where f denotes frequency. Human listeners reportedly prefer 1/f distributed random melodies to melodies with faster or slower dynamics. To test whether auditory neurons exhibit 1/f tuning, I recorded responses of neurons at three key stages of the central auditory pathway, namely, the inferior colliculus, thalamus and primary auditory cortex of anaesthetized ferrets to synthetic stimuli in which the fundamental frequency and the envelope were determined by statistically independent "1/f random walks".