title: Experience-Dependent, Layer-Specific Development of Divergent Thalamocortical Connectivity.
abstract: The main input to primary sensory cortex is via thalamocortical (TC) axons that form the greatest number of synapses in layer 4, but also synapse onto neurons in layer 6. The development of the TC input to layer 4 has been widely studied, but less is known about the development of the layer 6 input. Here, we show that, in neonates, the input to layer 6 is as strong as that to layer 4. Throughout the first postnatal week, there is an experience-dependent strengthening specific to layer 4, which correlates with the ability of synapses in layer 4, but not in layer 6, to undergo long-term potentiation (LTP). This strengthening consists of an increase in axon branching and the divergence of connectivity in layer 4 without a change in the strength of individual connections. We propose that experience-driven LTP stabilizes transient TC synapses in layer 4 to increase strength and divergence specifically in layer 4 over layer 6.
authors.affiliation: Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Crocker-Buque
authors.affiliation: Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Brown
authors.affiliation: Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Kind
authors.affiliation: Developmental Synaptic Plasticity Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA Current address: Lilly UK, Erl Wood Manor, Windlesham, UK.
authors.forename: John T R
authors.initials: JT
authors.lastname: Isaac
authors.affiliation: Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK.
authors.forename: Michael I
authors.initials: MI
authors.lastname: Daw
mesh_terms: D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D004558:Electric Stimulation; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology; D056347:Neuroanatomical Tract-Tracing Techniques; D018408:Patch-Clamp Techniques; D044302:Receptor, Serotonin, 5-HT1B / Q000378:metabolism; D013003:Somatosensory Cortex / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D013788:Thalamus / Q000166:cytology / Q000187:drug effects / Q000254:growth & development / Q000502:physiology*; D046509:Tissue Culture Techniques; D055698:Touch Perception / Q000502:physiology; D014738:Vibrissae / Q000502:physiology
chemical_list: C000603631:HTR1B protein, mouse; D044302:Receptor, Serotonin, 5-HT1B
keywords: LTP; barrel cortex; plasticity; somatosensory