Population coding of natural sounds in the mammalian auditory system. (360G-Wellcome-086697_Z_08_Z)

Despite the recent advances in our understanding of sensory function, the neural representation of complex natural stimuli remains a mystery. This gap in our understanding can be attributed to two complex properties of sensory systems that are important under natural conditions, but are not addressed in typical laboratory experiments involving recordings of the responses of a single neuron to simple stimuli: (1) the response properties of sensory neurons are not static, but are constantly adapte d to match the current statistical properties of the stimulus and (2) the representation of complex stimuli is not confined to the response of a single neuron, but is distributed across the responses of an interconnected population. I plan to study these complex properties in the inferior colliculus (IC) of the auditory midbrain. I will record the responses of small populations of neurons simultaneously during the presentation of natural stimuli and characterize the response properties of these neurons using a variety of system identification and information theoretic techniques. I will also use these experimental results to develop a model that incorporates the effects of adaptation and population interconnectivity in predicting neural responses to natural sounds.