Figure 2: Single-unit recording penetrations in core (AAF and A1) auditory cortex of the three ferrets with early hearing loss. Part (a) shows a lateral view of the ferret cortex with the location of the core auditory areas of anterior auditory field (AAF) and primary auditory cortex (A1) indicated (boxed). Part (b) shows tracings of surface photographs of the positions of the recording penetrations ( ) made in each of the hearing impaired animals. Dotted lines approximate the borders of the auditory fields (after [20]).