A standard laboratory task of this type therefore Neratinib cell line involves multiple stimulus-response associations (Lalazar and Vaadia, 2008). The microcircuitry connecting sensory and motor cortices described here might help to implement these stimulus-response associations. It has been suggested that vibrissa-based object localization requires the brain to interpret contact between whisker and object in

the context of an internal reference signal indicating whisker location or phase (Curtis and Kleinfeld, 2009 and Diamond et al., 2008). This reference signal might consist of an efference copy generated by the inverse model driving goal-directed whisking. The circuits uncovered here may underlie mixing of whisking ISRIB manufacturer and contact signals and thus, might underlie computation of object location. Experiments were conducted according to National Institutes of Health guidelines for animal research and were approved

by the Institutional Animal Care and Use Committee at Janelia Farm Research Campus. For anterograde tracing we used adeno-associated virus (AAV; serotype 2/1) expressing eGFP (www.addgene.com) or tdTomato (a gift from J. Magee) under the CAG promoter. For sCRACM mapping experiments, we used AAV virus (serotype 2/1; in some experiments serotype 2/10) expressing either ChR2-venus (Petreanu et al., 2009) or ChR2-tdTomato (www.addgene.com). For retrograde tracing we used fluorescent LumaFluor microbeads (LumaFluor Inc.). C57BL/6J mice (Charles River) (13–16 days old) were anesthetized using an isoflurane-oxygen mixture and placed in a custom stereotactic apparatus. A small hole was drilled into the skull,

allowing insertion of a pulled glass pipette (Drummond) (tip diameter: 10–20 μm for virus; 40–60 μm for LumaFluor microbeads). For sCRACM experiments, coordinates were as follows (in mm, from bregma): vS1, 0.5 to 0.8 posterior, 2.9–3.3 lateral; vM1, 1.0−1.1 anterior, 0.60–0.75 lateral. Injections sites Isotretinoin were confirmed by post hoc histological analysis (Figures 1B, 3, 4, 5, 6, 7, and S1B–S1H). See Supplemental Experimental Procedures for further details. Brain slices were prepared as described (Bureau et al., 2006) 14 to 24 days after viral infections (see Supplemental Experimental Procedures). For vM1, the brain was tilted ∼10° to 15° forward during slicing to optimize the alignment of apical dendrites with the slice surface. When cutting from rostral to caudal, 1∼2 slices, ∼0.8–1.3 mm anterior to bregma, corresponding to the first and/or second slice containing a fused corpus callosum, were used. For vS1 slices, the brain was cut in the coronal plane. Only slices with prominent barrels (Figure S9B) were used (Petreanu et al., 2009). All recordings were performed at room temperature in circulating ACSF. For most experiments (except Figures 6B, S6F, S8B, and S8C) TTX (1 μM), 4-AP (100 μM), and CPP (5 μM) were added (Petreanu et al., 2009).