title: Whisker Deprivation Drives Two Phases of Inhibitory Synapse Weakening in Layer 4 of Rat Somatosensory Cortex.
abstract: Inhibitory synapse development in sensory neocortex is experience-dependent, with sustained sensory deprivation yielding fewer and weaker inhibitory synapses. Whether this represents arrest of synapse maturation, or a more complex set of processes, is unclear. To test this, we measured the dynamics of inhibitory synapse development in layer 4 of rat somatosensory cortex (S1) during continuous whisker deprivation from postnatal day 7, and in age-matched controls. In deprived columns, spontaneous miniature inhibitory postsynaptic currents (mIPSCs) and evoked IPSCs developed normally until P15, when IPSC amplitude transiently decreased, recovering by P16 despite ongoing deprivation. IPSCs remained normal until P22, when a second, sustained phase of weakening began. Delaying deprivation onset by 5 days prevented the P15 weakening. Both early and late phase weakening involved measurable reduction in IPSC amplitude relative to prior time points. Thus, deprivation appears to drive two distinct phases of active IPSC weakening, rather than simple arrest of synapse maturation.
authors: Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America.
authors: Melanie A
authors: MA
authors: Gainey
authors: Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America.
authors: Renna
authors: R
authors: Wolfe
authors: Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America.
authors: Olivia
authors: O
authors: Pourzia
authors: Department of Molecular and Cellular Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America.
authors: Daniel E
authors: DE
authors: Feldman
mesh_terms: D000818:Animals; D053444:Inhibitory Postsynaptic Potentials / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D018408:Patch-Clamp Techniques; D051381:Rats; D020318:Rats, Long-Evans; D012683:Sensory Deprivation / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D013569:Synapses / Q000502:physiology; D014738:Vibrissae / Q000502:physiology*