TY - JOUR T1 - Comparison of Plasticity <em>In Vivo</em> and <em>In Vitro</em> in the Developing Visual Cortex of Normal and Protein Kinase A RIβ-Deficient Mice JF - The Journal of Neuroscience JO - J. Neurosci. SP - 2108 LP - 2117 DO - 10.1523/JNEUROSCI.18-06-02108.1998 VL - 18 IS - 6 AU - Takao K. Hensch AU - Joshua A. Gordon AU - Eugene P. Brandon AU - G. Stanley McKnight AU - Rejean L. Idzerda AU - Michael P. Stryker Y1 - 1998/03/15 UR - http://www.jneurosci.org/content/18/6/2108.abstract N2 - Developing sensory systems are sculpted by an activity-dependent strengthening and weakening of connections. Long-term potentiation (LTP) and depression (LTD) in vitro have been proposed to model this experience-dependent circuit refinement. We directly compared LTP and LTD induction in vitro with plasticityin vivo in the developing visual cortex of a mouse mutant of protein kinase A (PKA), a key enzyme implicated in the plasticity of a diverse array of systems.In mice lacking the RIβ regulatory subunit of PKA, we observed three abnormalities of synaptic plasticity in layer II/III of visual cortexin vitro. These included an absence of (1) extracellularly recorded LTP, (2) depotentiation or LTD, and (3) paired-pulse facilitation. Potentiation was induced, however, by pairing low-frequency stimulation with direct depolarization of individual mutant pyramidal cells. Together these findings suggest that the LTP defect in slices lacking PKA RIβ lies in the transmission of sufficient net excitation through the cortical circuit.Nonetheless, functional development and plasticity of visual cortical responses in vivo after monocular deprivation did not differ from normal. Moreover, the loss of all responsiveness to stimulation of the originally deprived eye in most cortical cells could be restored by reverse suture of eyelids during the critical period in both wild-type and mutant mice. Such an activity-dependent increase in response would seem to require a mechanism like potentiation in vivo. Thus, the RIβ isoform of PKA is not essential for ocular dominance plasticity, which can proceed despite defects in several common in vitro models of neural plasticity. ER -