The point spread function

for deconvolution was generated by using a 2D Lorentz function with its half-width and half-length fitted to the half-width and half-length of each individual image. Both Syt1 antibodies (mouse monoclonal, 604.2, Synaptic Systems) were directly labeled with either ATTO 647N or ATTO 590 and diluted (1:200) with Tyrode solution before use. For surface pool staining, neurons were preincubated in 1 μM TTX at room temperature for 15 min. Antibody stainings were performed for 15 min on ice to suppress endocytosis. Stimulation in between stainings, however, had to be performed at room temperature. Cells were washed twice and fixed for 15 min in 4% PFA. We thank I. Herfort for the preparation of hippocampal neuron cultures and Drs. Roman Schmidt, Johanna Bückers, and Stefan Hell (MPI for Biophysical Chemistry, Göttingen, Germany) for their great help with dual-color-STED imaging. Y.H. was supported by BIBW2992 research buy a stipend from the Max-Planck Society. A.W. was funded through the Cluster of Excellence and DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain. V.H. was funded by the DFG (SFB 958/A01). E.N. was supported by a grant from the European Commission (Health-F2-2009-241498; Eurospin). J.K. was supported by grants from the DFG (ESF Euromembrane, SFB

629, SFB 944, and DFG EXC 1003, Cells in Motion Cluster of Excellence, Münster, Germany). “
“Nearly a century ago it was first observed that global brain activity, measured by electroencephalography nearly (EEG), exhibits distinct electrical patterns BKM120 ic50 corresponding to overt behavioral states (e.g., sleep, relaxation, alertness) (Berger, 1929 and Loomis et al., 1935). Several studies have demonstrated that subthreshold activity can be tightly correlated with specific behavioral states. For example, intracellular recordings during slow-wave sleep have shown that the membrane potential

of cortical neurons exhibits slow (<1 Hz, “up/down”) fluctuations that are suppressed during wakefulness (Steriade et al., 2001). Moreover, recent findings suggest that wakefulness itself may comprise multiple states characterized by distinct membrane potential dynamics (Crochet and Petersen, 2006, Okun et al., 2010 and Poulet and Petersen, 2008). In mouse barrel cortex, periods of quiet wakefulness are associated with large-amplitude, correlated fluctuations in membrane potential that are attenuated during active whisking (Crochet and Petersen, 2006 and Poulet and Petersen, 2008). These studies raise the possibility that distinct membrane potential dynamics may mediate state-dependent modes of sensory processing. Recent studies in mouse primary visual cortex (V1) have demonstrated that a particular behavioral state, locomotion, is correlated with increased responses to visual stimuli (Ayaz et al., 2013, Keller et al., 2012 and Niell and Stryker, 2010).