This study in Hearing Research took advantage of NeuroNexus 2D probes (A4x8-5mm-50-200-177-A32) to record in a rostral-caudal and dorsal-ventral plane in auditory cortex of the mouse. They were able to distinguish between the primary auditory cortex (A1) and the anterior auditory field (AAF) based on the direction of their tonotopic axes. The linear layout on each shank of the probes enabled laminar analyses to isolate single units in different cortical layers. The results from Tania Rinaldi-Barkat and Magdalena Solyga in the Brain & Sound Lab at Basel University demonstrate that A1 encodes spectral complexity while AAF does not.