Moreover, the relative timing between excitatory and inhibitory inputs is not significantly affected by the cable effects and does not vary as a function of distance from the soma, as indicated by the modeling work in the same study (Wehr and Zador, 2003). The equation of I (t, V) = Gr(V − Er) + Ge(t)(V − Ee) + Gi(t)(V − Ei) was used to derive

excitatory and inhibitory synaptic conductance, as previously reported (Anderson et al., 2000, Borg-Graham et al., 1998, Wehr and Zador, 2003, Wu et al., 2006, Wu et al., 2008 and Zhang et al., 2003). I indicates synaptic current at the time point of t; Gr and Er represent the resting conductance and membrane potential, RG7420 respectively; Ge and Gi are the excitatory and inhibitory synaptic conductance, respectively; V is

the holding voltage; and Ee (0mV) and Ei (−70mV) are the reversal potentials of excitatory and inhibitory currents, respectively. The actual clamping voltage V(t) was corrected by V(t) = Vh − Rs∗I(t). Rs was the compensated series resistance, while Vh was the holding voltage set by the amplifier. Junction potential (about selleck chemicals 12mV) was corrected. By holding the recorded cell at −70mV and 0mV, Ge and Gi were computated, which reflect pure excitatory and inhibitory synaptic inputs, respectively. Activation of NMDA receptors can be ignored when the cell is clamped at −70mV (Hestrin et al., 1990, Jahr and Stevens, 1990a, Jahr and Stevens, 1990b and Pinault, 1996). Thus, the evoked synaptic currents are primarily mediated by AMPA and GABAA receptors. The DSI for spike, membrane potential, or synaptic input responses evoked by opposing directions is calculated as (Ru

− Rd)/(Ru + Rd), where Ru is the response amplitude to upward FM sweeps and Rd is that to downward sweeps. We thank M. much Konishi, C.E. Carr, C. Koch, and S. Cassenaer for the discussion and comments to the manuscript and the study and A.D. Steele and J. Lin for critical reading and style checking. We thank H.A. Lester for the discussion of biophysical properties of neurons and space-clamping issues. This work was supported by grants to G.K.W. from the Broad Fellows Program in Brain Circuitry of the Broad Foundation and the California Institute of Technology. We also thank the Division of Biology of Caltech for generous support in providing us laboratory space. “
“Auditory feedback is critical for learning and maintaining complex motor skills ranging from musical performance to speech. For example, hearing loss prevents speech learning in children and degrades speech in adults (Petitto, 1993 and Waldstein, 1990).