title: Dynamics of phase-independent spectro-temporal tuning in primary auditory cortex of the awake ferret.
abstract: Tuning of cortical neurons is often measured as a static property, or during a steady-state regime, despite a number of studies suggesting that tuning depends on when it is measured during a neuron's response (e.g., onset vs. sustained vs. offset). We have previously shown that phase-locked tuning to feature transients evolves as a dynamic quantity from the onset of the sound. In this follow-up study, we examined the phase-independent tuning during feature transients. Based on previous results, we hypothesized phase-independent tuning should evolve on the same timescale as phase-locked tuning. We used stimuli of constant level, but alternating between flat spectro-temporal envelope and a modulated envelope with well-defined spectral density and temporal periodicity. This allowed the measure of changes in tuning to novel spectro-temporal content, as happens during running speech and other sounds with rapid transitions without a confounding change in sound level. For 95% of neurons, tuning changed significantly from the onset, over the course of the response. For a majority of these cells, the change occurred within the first 40ms following a feature onset, often even around 10-20ms. This solidifies the idea that tuning can change rapidly from onset tuning to the sustained, steady-state tuning.
authors.affiliation: Institute for Systems Research, University of Maryland, College Park, MD, USA. depireux@umd.edu
authors.forename: D A
authors.initials: DA
authors.lastname: Depireux
authors.forename: H D
authors.initials: HD
authors.lastname: Dobbins
authors.forename: P
authors.initials: P
authors.lastname: Marvit
authors.forename: B
authors.initials: B
authors.lastname: Shechter
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods*; D000818:Animals; D001303:Auditory Cortex / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D005289:Ferrets; D011930:Reaction Time / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*