Stability of spectro-temporal tuning over several seconds in primary auditory cortex of the awake ferret

• Published in: Neuroscience 2007-09, Vol.148 (3), p.806-814
• Main Authors: Shechter, B, Depireux, D.A
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Action Potentials - physiology; Animals; auditory cortex; Auditory Cortex - anatomy & histology; Auditory Cortex - physiology; auditory gratings; Auditory Pathways - physiology; Auditory Perception - physiology; Biological and medical sciences; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Evoked Potentials, Auditory - physiology; Ferrets; Fundamental and applied biological sciences. Psychology; Mustela putorius furo; neural dynamics; Neurology; Neuronal Plasticity - physiology; Neurons - physiology; Pitch Perception - physiology; Reaction Time - physiology; Signal Processing, Computer-Assisted; Time Factors; Time Perception - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2007.06.027

Abstract The steady-state spectro-temporal tuning of auditory cortical cells has been studied using a variety of broadband stimuli that characterize neurons by their steady-state responses to long duration stimuli, lasting from about a second to several minutes. Central sensory stations are thought to adapt in their response to stimuli presented over extended periods of time. For instance, we have previously shown that auditory cortical neurons display a second order of adaptation, whereby the rate of their adaptation to the repeated presentation of fixed alternating stimuli decreases with each presentation. The auditory grating (or ripple) method of characterizing central auditory neurons, and its extensions, have proven very effective. But these stimuli are typically used with spectro-temporal content held fixed over time-scales of seconds, introducing the possibility of rapid adaptation while the receptive field is being measured, whereas the neural response used to compute a spectro-temporal receptive field (STRF) assumes stationarity in the neural input/output function. We demonstrate dynamic changes in some parameters during the measurement of the STRF over a period of seconds, even absent of a relevant behavioral task. Specifically, we find in the primary auditory cortex of the awake ferret, small but systematic changes in duration and breadth of tuning of STRFs when comparing the early (0.25–1.75 s) and late (4.5–6 s) segments of the responses to these stimuli.