Precise development of functional and anatomical columns in the neocortex.
Sensory cortex is ordered into columns, each tuned to a subset of peripheral stimuli. To identify the principles underlying the construction of columnar architecture, we monitored the development of circuits in the rat barrel cortex, using laser-scanning photostimulation analysis of synaptic connectivity, reconstructions of axonal arbors, and in vivo whole-cell recording. Circuits impinging onto layer 2/3 neurons from layers 4 and 2/3 developed in a monotonic, precise progression, with little evidence for transient hyperinnervation at the level of cortical columns. Consistent with this, synaptic currents measured in layer 2/3 neurons at PND 8, just after these neurons ceased to migrate, revealed already spatially well-tuned receptive fields.
Bureau
Ingrid
I
Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA.
Shepherd
Gordon M G
GM
Svoboda
Karel
K
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000378:metabolism; D001931:Brain Mapping; D003712:Dendrites / Q000378:metabolism; D004558:Electric Stimulation; D066298:In Vitro Techniques; D007834:Lasers; D008564:Membrane Potentials; D019579:Neocortex / Q000033:anatomy & histology / Q000166:cytology / Q000254:growth & development* / Q000502:physiology; D009415:Nerve Net / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000145:classification / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation / Q000295:instrumentation / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D013569:Synapses / Q000145:classification / Q000502:physiology; D014738:Vibrissae / Q000294:innervation / Q000502:physiology