title: Spatial distribution of inhibitory synaptic connections during development of ferret primary visual cortex.
abstract: Intracortical inhibition in the primary visual cortex plays an important role in creating properties like orientation and direction selectivity. However, the development of the spatial pattern of inhibitory connections is largely unexplored. This was investigated in the present study. Tangential slices of layers 2/3 of ferret striate cortex were prepared for whole-cell patch clamp recordings, and presynaptic inhibitory inputs to pyramidal neurons were scanned by local photolysis of Nmoc-caged glutamate. Inhibitory synaptic currents (IPSCs) were first detected around postnatal day (P) 17. They originated locally around the recorded cells. Both the number and the total areas supplying the inhibitory inputs increased thereafter and peaked at the time around and shortly after eye opening (P29-37). A refinement period then followed in which the areas providing the majority of inhibitory inputs shrank from 600 microm around the recorded neurons to 200-300 microm in more mature animals (>/=P38). The amplitude of IPSCs increased progressively with increasing age. Long-range inhibitory inputs (>600 microm) were present around eye opening and they often developed into a clustered patchy pattern in more mature animals (>/=P38). In summary, our results show a refinement and clustering in the spatial pattern of inhibitory connections during postnatal development of ferret visual cortex.
authors.affiliation: Department of Anatomy and Neurobiology, University of Maryland at Baltimore, 685 West Baltimore Street, Baltimore, MD 21201-1509, USA. broer001@umaryland.edu
authors.forename: Bingzhong
authors.initials: B
authors.lastname: Chen
authors.forename: Kaoutar
authors.initials: K
authors.lastname: Boukamel
authors.forename: Joseph P-Y
authors.initials: JP
authors.lastname: Kao
authors.forename: Birgit
authors.initials: B
authors.lastname: Roerig
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation / Q000502:physiology; D048430:Cell Shape / Q000502:physiology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005289:Ferrets; D005971:Glutamates; D007395:Interneurons / Q000166:cytology / Q000502:physiology*; D009433:Neural Inhibition / Q000502:physiology*; D009434:Neural Pathways / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009924:Organ Culture Techniques; D018408:Patch-Clamp Techniques; D011930:Reaction Time / Q000502:physiology; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D014793:Visual Cortex / Q000166:cytology / Q000254:growth & development / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D005971:Glutamates; C109776:N-nitromandelyloxycarbonylglutamate; D005680:gamma-Aminobutyric Acid