title: Multiscale mapping of frequency sweep rate in mouse auditory cortex.
abstract: Functional organization is a key feature of the neocortex that often guides studies of sensory processing, development, and plasticity. Tonotopy, which arises from the transduction properties of the cochlea, is the most widely studied organizational feature in auditory cortex; however, in order to process complex sounds, cortical regions are likely specialized for higher order features. Here, motivated by the prevalence of frequency modulations in mouse ultrasonic vocalizations and aided by the use of a multiscale imaging approach, we uncover a functional organization across the extent of auditory cortex for the rate of frequency modulated (FM) sweeps. In particular, using two-photon Ca2+imaging of layer 2/3 neurons, we identify a tone-insensitive region at the border of AI and AAF. This central sweep region behaves fundamentally differently from nearby neurons in AI and AII, responding preferentially to fast FM sweeps but not to tones or bandlimited noise. Together these findings define a second dimension of organization in the mouse auditory cortex for sweep rate complementary to that of tone frequency.
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, MD 21205, USA. Electronic address: john.issa@gmail.com.
authors.forename: John B
authors.initials: JB
authors.lastname: Issa
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, MD 21205, USA.
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Haeffele
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, WBSB, Baltimore, MD 21205, USA.
authors.forename: Eric D
authors.initials: ED
authors.lastname: Young
authors.affiliation: Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Ross Building, Room 713, 720 Rutland Avenue, Baltimore, MD 21205, USA; Center for Cell Dynamics, The Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, MD 21205, USA; Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, WBSB, Baltimore, MD 21205, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Yue
mesh_terms: D000161:Acoustic Stimulation; D000818:Animals; D001303:Auditory Cortex / Q000378:metabolism / Q000502:physiology*; D015374:Biosensing Techniques; D001931:Brain Mapping / Q000379:methods*; D002118:Calcium / Q000378:metabolism; D005072:Evoked Potentials, Auditory; D017930:Genes, Reporter; D008822:Mice, Transgenic; D036641:Microscopy, Fluorescence, Multiphoton; D009473:Neuronal Plasticity; D010898:Pitch Perception; D013997:Time Factors
chemical_list: D002118:Calcium
keywords: Auditory cortex; Cortical organization; Frequency modulated sweeps; In vivo two-photon calcium imaging