Data were collected from awake monkeys that were conditioned to sit quietly in the primate chair and accept painless head restraint, but were not required to attend or respond to the auditory stimuli. A1 yields robust and consistent responses to suprathreshold tones under these conditions (O'Connell et al., 2011;Steinschneider et al., 2008), comparable in quality to those generated by attended auditory stimuli (Lakatos et al., 2009). Laminar profiles of auditory-evoked LFPs and MUA were recorded with linear array multielectrodes (100 or 200 μm inter-contact spacing) positioned for each experiment so that they straddled the layers of A1. To illustrate the recording preparation and methods, Figure 1 depicts averaged laminar profiles of response to the “best frequency” (BF) tone of one penetration site in A1 (see methods for details on BF determination). Laminar LFP profiles are shown in both raw, line plot (A) and in a more intuitive color plot (B) formats, both of which are used in subsequent figures. On the right (C) is the CSD profile derived from the LFP profile, with selected MUA recordings superimposed to help connect
