title: Temporal variability of spectro-temporal receptive fields in the anesthetized auditory cortex.
abstract: Temporal variability of neuronal response characteristics during sensory stimulation is a ubiquitous phenomenon that may reflect processes such as stimulus-driven adaptation, top-down modulation or spontaneous fluctuations. It poses a challenge to functional characterization methods such as the receptive field, since these often assume stationarity. We propose a novel method for estimation of sensory neurons' receptive fields that extends the classic static linear receptive field model to the time-varying case. Here, the long-term estimate of the static receptive field serves as the mean of a probabilistic prior distribution from which the short-term temporally localized receptive field may deviate stochastically with time-varying standard deviation. The derived corresponding generalized linear model permits robust characterization of temporal variability in receptive field structure also for highly non-Gaussian stimulus ensembles. We computed and analyzed short-term auditory spectro-temporal receptive field (STRF) estimates with characteristic temporal resolution 5-30 s based on model simulations and responses from in total 60 single-unit recordings in anesthetized Mongolian gerbil auditory midbrain and cortex. Stimulation was performed with short (100 ms) overlapping frequency-modulated tones. Results demonstrate identification of time-varying STRFs, with obtained predictive model likelihoods exceeding those from baseline static STRF estimation. Quantitative characterization of STRF variability reveals a higher degree thereof in auditory cortex compared to midbrain. Cluster analysis indicates that significant deviations from the long-term static STRF are brief, but reliably estimated. We hypothesize that the observed variability more likely reflects spontaneous or state-dependent internal fluctuations that interact with stimulus-induced processing, rather than experimental or stimulus design.
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Department of Medical Physics and Acoustics, Carl von Ossietzky University Oldenburg, Germany.
authors.forename: Arne F
authors.initials: AF
authors.lastname: Meyer
authors.affiliation: Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology Magdeburg, Germany.
authors.forename: Jan-Philipp
authors.initials: JP
authors.lastname: Diepenbrock
authors.affiliation: Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology Magdeburg, Germany ; Department of Neuroprosthetics, Institute of Biology, Otto-von-Guericke University Magdeburg, Germany.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Ohl
authors.affiliation: Medizinische Physik and Cluster of Excellence Hearing4all, Department of Medical Physics and Acoustics, Carl von Ossietzky University Oldenburg, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Anemüller
keywords: auditory cortex; generalized linear model; inferior colliculus; receptive field; sensory coding; time-varying; zero-mean prior