The functional asymmetry of auditory cortex is reflected in the organization of local cortical circuits.
The primary auditory cortex (A1) is organized tonotopically, with neurons sensitive to high and low frequencies arranged in a rostro-caudal gradient. We used laser scanning photostimulation in acute slices to study the organization of local excitatory connections onto layers 2 and 3 (L2/3) of the mouse A1. Consistent with the organization of other cortical regions, synaptic inputs along the isofrequency axis (orthogonal to the tonotopic axis) arose predominantly within a column. By contrast, we found that local connections along the tonotopic axis differed from those along the isofrequency axis: some input pathways to L3 (but not L2) arose predominantly out-of-column. In vivo cell-attached recordings revealed differences between the sound-responsiveness of neurons in L2 and L3. Our results are consistent with the hypothesis that auditory cortical microcircuitry is specialized to the one-dimensional representation of frequency in the auditory cortex.
Oviedo
Hysell V
HV
Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, USA.
Bureau
Ingrid
I
Svoboda
Karel
K
Zador
Anthony M
AM
D000161:Acoustic Stimulation / Q000379:methods; D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D016880:Anisotropy; D001303:Auditory Cortex / Q000166:cytology / Q000502:physiology*; D001931:Brain Mapping; D002772:Cholera Toxin / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology*; D018698:Glutamic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D018613:Microscopy, Confocal / Q000379:methods; D009415:Nerve Net / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011571:Psychoacoustics; D051381:Rats; D020318:Rats, Long-Evans; D018709:Statistics, Nonparametric; D013997:Time Factors
D000276:Adjuvants, Immunologic; D000596:Amino Acids; C098463:dolaisoleucine; D018698:Glutamic Acid; D002772:Cholera Toxin