, 2005) (Figure S1). Spike width was measured as the width of the extracellular spike waveform at half-amplitude (Barthó et al., 2004). All data analysis was performed in MATLAB (MathWorks). Spindles were detected semiautomatically

from the thalamic multiunit activity (MUA) separately for each shank (for details, see Figure S1). After automatic detection, spindles were verified visually, and false detections were deleted. Spindle phases were estimated at the maximal amplitude of Morlet wavelet transform using scales between 7 and 20 Hz. Jitter was defined as the SD of spike distances from spindle peak during a given cycle. For cycle-by-cycle cross-correlograms, only the reference spikes contained within the given cycle were considered. Number of spikes per burst in a cycle was estimated as the number of spikes fired, given the NVP-BGJ398 cell participated in a given cycle. Spike numbers per cycle, participation probability, and spikes GSI-IX cost per burst (Figures 5D, 6, and S6) were calculated for each spindle length category

averaged across all cells in all animals. Following the neurophysiological recordings, animals were transcardially perfused first with saline, and then with 400–500 ml of fixative containing 4% paraformaldehyde, 0.05% glutaraldehyde in 0.1 M phosphate buffer. Tissue blocks were cut on a Vibratome into 50 μm coronal sections. Electrode tracks were reconstructed from Nissl-stained slices (chronic experiments) or fluorescently counterstained for parvalbumin (acute experiments, the silicon probe

was dipped in DII solution beforehand). After lesion experiments, the fixed brain was cut into 50-μm-thick sections and or fluorescently counterstained for the neuronal marker NeuN to visualize the spread of lesion. The immunofluorescence stainings were performed according to the following protocol. Sections were intensively washed with PB and then treated with a blocking solution containing 5% normal goat serum (NGS) and 1% Triton-X for 45 min at room temperature. The primary antibody against PV (rabbit 1:3,000; Swant) and/or NeuN (mouse 1:300; Millipore) was diluted in PB containing 0.1% NGS and 0.2% Triton-X. After primary antibody incubation (overnight at room temperature), sections were treated with the secondary antibody Alexa-488-conjugated goat anti-rabbit or goat and anti-mouse immunoglobulin (Ig)G and/or Alexa-594-conjugated goat anti-rabbit or goat anti-mouse IgG for 2 hr at room temperature. After further PB washes, sections were mounted in vectashield (Vector) and imaged using epifluorescent microscopy (Zeiss). We thank Drs. G. Buzsáki, Z. Nusser, I. Soltész, J. Szabadics, and A. Lüthi for critical comments on the manuscript. The studies were supported by grants from the Hungarian Scientific Research Fund (OTKA NF101773, K109754 and K81357) the National Office for Research and Technology (NKTH-ANR, Neurogen), the Hungarian Brain Research Program – Grant No.